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Aug 19, 2009 - 2 comments

My drug interactions from drugs.com!!!!!

Generated on Aug 19, 2009

Note: The following drug(s) / condition(s) / allergies could not be checked for interactions:
dronedarone (Multaq)
Interactions between your selected drugs
theophylline ⇔ bisoprolol

Applies to:Theo-Dur (theophylline), bisoprolol

Major Drug Interaction

GENERALLY AVOID: The pharmacologic effects of theophyllines and beta-blockers are opposite. Nonselective and high doses of cardioselective beta-blockers may cause severe or fatal bronchospasm by opposing theophylline-induced bronchodilation. Ophthalmic beta-blockers undergo significant systemic absorption and may also interact. In addition, propranolol and other beta-blockers may reduce the CYP450 hepatic metabolism of theophylline, and serum theophylline levels may be increased. MANAGEMENT: Oral and ophthalmic nonselective beta-blockers (e.g., carteolol, carvedilol, levobunolol, metipranolol, nadolol, oxprenolol, penbutolol, pindolol, propranolol, sotalol, and timolol) are considered contraindicated in patients with bronchospastic diseases. Cardioselective beta-blockers should generally be avoided, or used with extreme caution if no other alternatives are available and the benefits outweigh the risks of potentially severe bronchospasm. If patients do receive this combination, they should be closely monitored for increased serum theophylline levels but decreased bronchodilatory effectiveness.
ibuprofen ⇔ bisoprolol

Applies to:Motrin (ibuprofen), bisoprolol

Moderate Drug Interaction

MONITOR: Nonsteroidal anti-inflammatory drugs (NSAIDs) may attenuate the antihypertensive effect of beta-blockers. The proposed mechanism is NSAID-induced inhibition of renal prostaglandin synthesis, which results in unopposed pressor activity producing hypertension. In addition, NSAIDs can cause fluid retention, which also affects blood pressure. Indomethacin and piroxicam have been reported to have greater attenuating effects than other NSAIDs, and indomethacin effects may be significant in patients with eclampsia. MANAGEMENT: Patients receiving a beta-blocker who require prolonged (greater than 1 week) concomitant therapy with an NSAID should have blood pressure monitored more closely following initiation, discontinuation, or change of dosage of the NSAID. The interaction is not expected to occur with low doses (e.g., low-dose aspirin) or intermittent short-term administration of NSAIDs.
phenytoin ⇔ clonazepam

Applies to:Dilantin (phenytoin), Klonopin (clonazepam)

Moderate Drug Interaction

MONITOR: Coadministration with some benzodiazepines may alter the serum concentrations of phenytoin. Both increases and decreases have been cited by case reports and pharmacokinetic studies, while a few reported no changes. The exact mechanism of interaction is unknown, and it is uncertain whether other hydantoins are also affected. Phenytoin toxicity has been reported in patients treated with various benzodiazepines, including clobazam, chlordiazepoxide, clonazepam, and diazepam. Conversely, phenytoin may reduce the plasma concentrations of some benzodiazepines by inducing their metabolism via hepatic microsomal enzymes. In one study, pretreatment with phenytoin (4.3 mg/kg/day for 19 days) increased the clearance of clonazepam (0.03 mg/kg single oral dose) by 46% to 58% and decreased its half-life by 31% in eight healthy volunteers. In another study, mean peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of midazolam (15 mg oral dose) in six epileptic patients treated concomitantly with phenytoin or carbamazepine were 7.4% and 5.7%, respectively, of those observed in seven control subjects who were not receiving enzyme inducers. The low plasma midazolam concentrations in the patient group were associated with reduced pharmacodynamic effects as compared with control subjects. MANAGEMENT: Pharmacologic response and serum hydantoin levels should be monitored more closely whenever a benzodiazepine is added to or withdrawn from therapy, and the hydantoin dosage adjusted as necessary. Patients should be advised to contact their physician if they experience symptoms of hydantoin toxicity such as nausea, vomiting, tremors, ataxia, lethargy, slurred speech, visual disturbances, or changes in mental status. The potential for diminished or inadequate benzodiazepine effects should be considered during concomitant use with phenytoin.
carbamazepine ⇔ theophylline

Applies to:Tegretol (carbamazepine), Theo-Dur (theophylline)

Moderate Drug Interaction

MONITOR: Carbamazepine may decrease theophylline serum levels. Also, theophyllines may decrease serum levels and effects of carbamazepine. The mechanisms may be related to induction of hepatic CYP450 metabolism. MANAGEMENT: Close observation for clinical and laboratory evidence of altered effects is recommended for both agents. Patients should be advised to notify their physician if they experience loss of therapeutic effects.
carbamazepine ⇔ clonazepam

Applies to:Tegretol (carbamazepine), Klonopin (clonazepam)

Moderate Drug Interaction

MONITOR: Carbamazepine may reduce serum clonazepam levels. The mechanism may be related to induction of metabolism. The risk of CNS-depressant side effects, such as sedation and apathy, may be increased with this combination. MANAGEMENT: If these drugs must be used together, observation for clinical and laboratory evidence of altered clonazepam effect is recommended.
carbamazepine ⇔ phenytoin

Applies to:Tegretol (carbamazepine), Dilantin (phenytoin)

Moderate Drug Interaction

MONITOR: Hydantoins may decrease carbamazepine levels, and carbamazepine may have variable effects on hydantoin levels. The mechanism may be related to induction of CYP450 hepatic metabolism of carbamazepine and alteration of hydantoin metabolism. MANAGEMENT: Close observation for clinical and laboratory evidence of altered effects is recommended, particularly when one drug is started or discontinued. Patients should be advised to notify their physician if they experience loss of seizure control or symptoms of hydantoin toxicity (drowsiness, visual disturbances, change in mental status, nausea, or ataxia).
carbamazepine ⇔ fluoxetine

Applies to:Tegretol (carbamazepine), Prozac (fluoxetine)

Moderate Drug Interaction

MONITOR: Fluoxetine may inhibit the hepatic metabolism of carbamazepine. Carbamazepine toxicity is possible. Data have been conflicting and one study has reported no significant pharmacokinetic interaction. A case of toxic serotonin syndrome has occurred in one patient who was taking both carbamazepine and fluoxetine. MANAGEMENT: Until more information is available, close observation for clinical and laboratory evidence of carbamazepine toxicity is recommended. Dose adjustments may be required. Patients should be advised to report possible symptoms of carbamazepine toxicity (nausea, visual disturbances, dizziness, or ataxia) or serotonin syndrome (uncontrollable shivering, agitation, incoordination, restlessness, involuntary movements, hyperreflexia, and hyperarousal).
prednisone ⇔ pyridostigmine

Applies to:prednisone, Mestinon (pyridostigmine)

Moderate Drug Interaction

ADJUST DOSE: Corticosteroids and adrenocorticotropic agents may diminish the therapeutic effects of acetylcholinesterase inhibitors in myasthenia gravis. The mechanism of interaction is unknown. Marked deterioration in muscle strength has been reported in patients with myasthenia gravis shortly after the initiation of corticosteroid therapy, particularly when high dosages were used. In most cases, the decline in muscular function was relatively refractory to acetylcholinesterase inhibitors. However, clinical improvement generally occurs during prolonged corticosteroid therapy when administered properly. MANAGEMENT: Corticosteroid therapy should be instituted at relatively low dosages (15 to 25 mg/day of prednisone or equivalent) and in a controlled setting in patients with myasthenia gravis. Respiratory support should be available, and the dosage should be increased stepwise as tolerated (approximately 5 mg/day of prednisone or equivalent at 2- to 3-day intervals until marked clinical improvement or a dosage of 50 mg/day is reached). Dose reductions of the acetylcholinesterase inhibitor may be required as symptoms improve, which often may be delayed and gradual.
pyridostigmine ⇔ fludrocortisone

Applies to:Mestinon (pyridostigmine), Florinef (fludrocortisone)

Moderate Drug Interaction

ADJUST DOSE: Corticosteroids and adrenocorticotropic agents may diminish the therapeutic effects of acetylcholinesterase inhibitors in myasthenia gravis. The mechanism of interaction is unknown. Marked deterioration in muscle strength has been reported in patients with myasthenia gravis shortly after the initiation of corticosteroid therapy, particularly when high dosages were used. In most cases, the decline in muscular function was relatively refractory to acetylcholinesterase inhibitors. However, clinical improvement generally occurs during prolonged corticosteroid therapy when administered properly. MANAGEMENT: Corticosteroid therapy should be instituted at relatively low dosages (15 to 25 mg/day of prednisone or equivalent) and in a controlled setting in patients with myasthenia gravis. Respiratory support should be available, and the dosage should be increased stepwise as tolerated (approximately 5 mg/day of prednisone or equivalent at 2- to 3-day intervals until marked clinical improvement or a dosage of 50 mg/day is reached). Dose reductions of the acetylcholinesterase inhibitor may be required as symptoms improve, which often may be delayed and gradual.
phenytoin ⇔ fluoxetine

Applies to:Dilantin (phenytoin), Prozac (fluoxetine)

Moderate Drug Interaction

MONITOR: Fluoxetine may increase serum hydantoin levels. The mechanism is unknown, but may be related to inhibition of hepatic CYP450 2C9 and 2C19 hydantoin metabolism. MANAGEMENT: Close observation for clinical and laboratory evidence of hydantoin toxicity is recommended if these drugs must be used together. Patients should be advised to notify their physician if they experience symptoms of possible hydantoin toxicity, including drowsiness, visual disturbances, change in mental status, seizures, nausea, or ataxia.
clonazepam ⇔ fluoxetine

Applies to:Klonopin (clonazepam), Prozac (fluoxetine)

Moderate Drug Interaction

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
carbamazepine ⇔ metoclopramide

Applies to:Tegretol (carbamazepine), Reglan (metoclopramide)

Moderate Drug Interaction

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
phenytoin ⇔ metoclopramide

Applies to:Dilantin (phenytoin), Reglan (metoclopramide)

Moderate Drug Interaction

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
clonazepam ⇔ metoclopramide

Applies to:Klonopin (clonazepam), Reglan (metoclopramide)

Moderate Drug Interaction

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
metoclopramide ⇔ zonisamide

Applies to:Reglan (metoclopramide), Zonegran (zonisamide)

Moderate Drug Interaction

MONITOR: Central nervous system- and/or respiratory-depressant effects may be additively or synergistically increased in patients taking multiple drugs that cause these effects, especially in elderly or debilitated patients. MANAGEMENT: During concomitant use of these drugs, patients should be monitored for potentially excessive or prolonged CNS and respiratory depression. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
theophylline ⇔ phenytoin

Applies to:Theo-Dur (theophylline), Dilantin (phenytoin)

Moderate Drug Interaction

MONITOR: Phenytoin has been reported to increase the clearance of theophylline by 40% to 50%, presumably by enhancing the hepatic CYP450 metabolism of theophylline. Also, coadministration of theophylline has been reported to lower serum phenytoin concentrations. Other hydantoins and hepatically metabolized methylxanthines may also interact. MANAGEMENT: Management consists of monitoring clinical response and serum concentrations of both drugs and adjusting dosages as necessary. Patients should be advised to report loss of seizure control or worsening of respiratory symptoms to their physician.
theophylline ⇔ albuterol

Applies to:Theo-Dur (theophylline), ProAir HFA (albuterol)

Moderate Drug Interaction

MONITOR: Theophylline and beta-2 agonists are commonly used together to produce bronchodilation. However, increased or decreased theophylline levels, hypokalemia, and arrhythmias have been reported during their concomitant use. Data have been conflicting. The mechanism is unknown. MANAGEMENT: Until more information is available, it may be appropriate to regularly monitor patient response to therapy and serum potassium levels during coadministration of theophylline and beta-2 agonists, and adjust the dosages as necessary. Patients should be advised to notify their doctor if they experience worsening of their respiratory symptoms, palpitations, symptoms of hypokalemia (e.g., weakness, lethargy, muscle pains or cramps), or signs of theophylline toxicity (e.g., nausea, vomiting, diarrhea, headache, restlessness, insomnia, seizures, irregular heartbeats).
theophylline ⇔ formoterol

Applies to:Theo-Dur (theophylline), Symbicort (budesonide/formoterol)

Moderate Drug Interaction

MONITOR: Theophylline and beta-2 agonists are commonly used together to produce bronchodilation. However, increased or decreased theophylline levels, hypokalemia, and arrhythmias have been reported during their concomitant use. Data have been conflicting. The mechanism is unknown. MANAGEMENT: Until more information is available, it may be appropriate to regularly monitor patient response to therapy and serum potassium levels during coadministration of theophylline and beta-2 agonists, and adjust the dosages as necessary. Patients should be advised to notify their doctor if they experience worsening of their respiratory symptoms, palpitations, symptoms of hypokalemia (e.g., weakness, lethargy, muscle pains or cramps), or signs of theophylline toxicity (e.g., nausea, vomiting, diarrhea, headache, restlessness, insomnia, seizures, irregular heartbeats).
phenytoin ⇔ prednisone

Applies to:Dilantin (phenytoin), prednisone

Moderate Drug Interaction

MONITOR: Phenytoin and other hydantoins may induce the CYP450 3A4 hepatic metabolism of corticosteroids and increase their clearance and decrease their half-lives, possibly reducing their therapeutic efficacy. In addition, results of the dexamethasone adrenal suppression test may be unreliable in patients concurrently taking phenytoin. Hydrocortisone appears to be affected to a lesser extent than other corticosteroids. Some corticosteroids have also been reported to cause increases or decreases in serum phenytoin levels; however, data have been inconsistent. MANAGEMENT: Patients should be closely monitored for clinical and laboratory evidence of reduced corticosteroid effects and changes in phenytoin concentrations during concomitant therapy. Some patients may require increased corticosteroid dosages.
phenytoin ⇔ fludrocortisone

Applies to:Dilantin (phenytoin), Florinef (fludrocortisone)

Moderate Drug Interaction

MONITOR: Phenytoin and other hydantoins may induce the CYP450 3A4 hepatic metabolism of corticosteroids and increase their clearance and decrease their half-lives, possibly reducing their therapeutic efficacy. In addition, results of the dexamethasone adrenal suppression test may be unreliable in patients concurrently taking phenytoin. Hydrocortisone appears to be affected to a lesser extent than other corticosteroids. Some corticosteroids have also been reported to cause increases or decreases in serum phenytoin levels; however, data have been inconsistent. MANAGEMENT: Patients should be closely monitored for clinical and laboratory evidence of reduced corticosteroid effects and changes in phenytoin concentrations during concomitant therapy. Some patients may require increased corticosteroid dosages.
carbamazepine ⇔ prednisone

Applies to:Tegretol (carbamazepine), prednisone

Moderate Drug Interaction

MONITOR: Carbamazepine may decrease the plasma concentrations and systemic effects of both endogenous and exogenous corticosteroids. The mechanism is accelerated corticosteroid metabolism due to induction of the CYP450 3A4 enzymatic pathway by carbamazepine. MANAGEMENT: Patients treated concomitantly with carbamazepine may require higher dosages of corticosteroids or adrenocorticotropic agents. Pharmacologic response to these agents should be monitored more closely whenever carbamazepine is added to or withdrawn from therapy in patients stabilized on their existing corticosteroid or adrenocorticotropic regimen, and the dosage(s) adjusted as necessary.
carbamazepine ⇔ fludrocortisone

Applies to:Tegretol (carbamazepine), Florinef (fludrocortisone)

Moderate Drug Interaction

MONITOR: Carbamazepine may decrease the plasma concentrations and systemic effects of both endogenous and exogenous corticosteroids. The mechanism is accelerated corticosteroid metabolism due to induction of the CYP450 3A4 enzymatic pathway by carbamazepine. MANAGEMENT: Patients treated concomitantly with carbamazepine may require higher dosages of corticosteroids or adrenocorticotropic agents. Pharmacologic response to these agents should be monitored more closely whenever carbamazepine is added to or withdrawn from therapy in patients stabilized on their existing corticosteroid or adrenocorticotropic regimen, and the dosage(s) adjusted as necessary.
ibuprofen ⇔ prednisone

Applies to:Motrin (ibuprofen), prednisone

Moderate Drug Interaction

MONITOR: The combined use of oral corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs) may increase the potential for serious gastrointestinal (GI) toxicity, including inflammation, bleeding, ulceration, and perforation. In a large, case-control study of elderly patients, those who used corticosteroids and NSAIDs concurrently had an estimated relative risk (RR) for peptic ulcer disease and GI hemorrhage of 14.6 compared to those who used neither. Oral corticosteroid use was associated with a doubling of the risk (estimated RR = 2.0), but the risk was confined to those who also used NSAIDs. It is possible that both categories of agents are ulcerogenic and have additive effects on the GI mucosa during coadministration. Some investigators have also suggested that the primary effect of corticosteroids in this interaction is to delay healing of erosions caused by NSAIDs rather than cause de novo ulcerations. MANAGEMENT: Caution is advised if oral corticosteroids and NSAIDs are used together, especially in patients with a prior history of peptic ulcer disease or GI bleeding and in elderly and debilitated patients. During concomitant therapy, patients should be advised to take the medications with food and to immediately report signs and symptoms of GI ulceration and bleeding such as severe abdominal pain, dizziness, lightheadedness, and the appearance of black, tarry stools. The selective use of prophylactic anti-ulcer therapy (e.g., antacids, H2-antagonists) may be considered.
ibuprofen ⇔ fludrocortisone

Applies to:Motrin (ibuprofen), Florinef (fludrocortisone)

Moderate Drug Interaction

MONITOR: The combined use of oral corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs) may increase the potential for serious gastrointestinal (GI) toxicity, including inflammation, bleeding, ulceration, and perforation. In a large, case-control study of elderly patients, those who used corticosteroids and NSAIDs concurrently had an estimated relative risk (RR) for peptic ulcer disease and GI hemorrhage of 14.6 compared to those who used neither. Oral corticosteroid use was associated with a doubling of the risk (estimated RR = 2.0), but the risk was confined to those who also used NSAIDs. It is possible that both categories of agents are ulcerogenic and have additive effects on the GI mucosa during coadministration. Some investigators have also suggested that the primary effect of corticosteroids in this interaction is to delay healing of erosions caused by NSAIDs rather than cause de novo ulcerations. MANAGEMENT: Caution is advised if oral corticosteroids and NSAIDs are used together, especially in patients with a prior history of peptic ulcer disease or GI bleeding and in elderly and debilitated patients. During concomitant therapy, patients should be advised to take the medications with food and to immediately report signs and symptoms of GI ulceration and bleeding such as severe abdominal pain, dizziness, lightheadedness, and the appearance of black, tarry stools. The selective use of prophylactic anti-ulcer therapy (e.g., antacids, H2-antagonists) may be considered.
ibuprofen ⇔ budesonide

Applies to:Motrin (ibuprofen), Symbicort (budesonide/formoterol)

Moderate Drug Interaction

MONITOR: The combined use of oral corticosteroids and nonsteroidal anti-inflammatory drugs (NSAIDs) may increase the potential for serious gastrointestinal (GI) toxicity, including inflammation, bleeding, ulceration, and perforation. In a large, case-control study of elderly patients, those who used corticosteroids and NSAIDs concurrently had an estimated relative risk (RR) for peptic ulcer disease and GI hemorrhage of 14.6 compared to those who used neither. Oral corticosteroid use was associated with a doubling of the risk (estimated RR = 2.0), but the risk was confined to those who also used NSAIDs. It is possible that both categories of agents are ulcerogenic and have additive effects on the GI mucosa during coadministration. Some investigators have also suggested that the primary effect of corticosteroids in this interaction is to delay healing of erosions caused by NSAIDs rather than cause de novo ulcerations. MANAGEMENT: Caution is advised if oral corticosteroids and NSAIDs are used together, especially in patients with a prior history of peptic ulcer disease or GI bleeding and in elderly and debilitated patients. During concomitant therapy, patients should be advised to take the medications with food and to immediately report signs and symptoms of GI ulceration and bleeding such as severe abdominal pain, dizziness, lightheadedness, and the appearance of black, tarry stools. The selective use of prophylactic anti-ulcer therapy (e.g., antacids, H2-antagonists) may be considered.
fluoxetine ⇔ methylphenidate

Applies to:Prozac (fluoxetine), Concerta (methylphenidate)

Moderate Drug Interaction

MONITOR: The coadministration with methylphenidate may increase the plasma concentrations of selective serotonin reuptake inhibitors (SSRIs). According to the manufacturer, human pharmacologic studies have shown that methylphenidate may inhibit the metabolism of SSRIs, and there have been reports that methylphenidate augments the clinical response to SSRIs. MANAGEMENT: Pharmacologic response to SSRIs should be monitored more closely whenever methylphenidate (racemic) or dexmethylphenidate (the more pharmacologically active d-enantiomer) is added to or withdrawn from therapy, and the SSRI dosage adjusted as necessary.
carbamazepine ⇔ zonisamide

Applies to:Tegretol (carbamazepine), Zonegran (zonisamide)

Moderate Drug Interaction

MONITOR: The coadministration with drugs that are inducers of the CYP450 3A4 isoenzyme may decrease the plasma concentrations and efficacy of zonisamide. The mechanism is accelerated clearance of zonisamide due to enhanced CYP450 3A4 activity. MANAGEMENT: Pharmacologic response to zonisamide should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the zonisamide dosage adjusted as necessary. Patients should be advised to notify their physician if they experience loss of seizure control.
phenytoin ⇔ zonisamide

Applies to:Dilantin (phenytoin), Zonegran (zonisamide)

Moderate Drug Interaction

MONITOR: The coadministration with drugs that are inducers of the CYP450 3A4 isoenzyme may decrease the plasma concentrations and efficacy of zonisamide. The mechanism is accelerated clearance of zonisamide due to enhanced CYP450 3A4 activity. MANAGEMENT: Pharmacologic response to zonisamide should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the zonisamide dosage adjusted as necessary. Patients should be advised to notify their physician if they experience loss of seizure control.
fluoxetine ⇔ metoclopramide

Applies to:Prozac (fluoxetine), Reglan (metoclopramide)

Moderate Drug Interaction

MONITOR: Coadministration of metoclopramide with serotonin reuptake inhibitors has been associated with development of the serotonin syndrome and severe extrapyramidal reactions. The exact mechanism is unknown but may involve a pharmacodynamic interaction between serotonergic and antidopaminergic effects of the drugs. A pharmacokinetic interaction is also possible, since metoclopramide and most serotonin reuptake inhibitors are primarily or at least partially metabolized by the CYP450 2D6 isoenzyme. Theoretically, competitive and/or noncompetitive inhibition may lead to elevated plasma levels of one or both drugs, resulting in excessive central serotonergic and antidopaminergic effects. In a published case report, a 72-year-old woman treated with sertraline and a 32-year-old woman treated with venlafaxine developed movement disorders and symptoms consistent with the serotonin syndrome shortly after single doses of metoclopramide. Both cases resolved following treatment with diazepam, and the patients resumed their sertraline and venlafaxine therapy without further incident. Serotonin syndrome is a rare but serious and potentially fatal condition thought to result from hyperstimulation of brainstem 5-HT1A and 2A receptors. Symptoms of the serotonin syndrome may include mental status changes such as irritability, altered consciousness, confusion, hallucinations, and coma; autonomic dysfunction such as tachycardia, hyperthermia, diaphoresis, shivering, blood pressure lability, and mydriasis; neuromuscular abnormalities such as hyperreflexia, myoclonus, tremor, rigidity, and ataxia; and gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, and diarrhea. MANAGEMENT: Caution is advised if metoclopramide is prescribed in combination with serotonin reuptake inhibitors. Patients should be monitored for symptoms of the serotonin syndrome as well as development of extrapyramidal reactions such as involuntary twitching of the jaw and limbs, teeth clenching, severe jerking, trismus, and tongue and neck stiffness. If serotonin syndrome develops or is suspected during the course of therapy, all serotonergic agents should be discontinued immediately and supportive care rendered as necessary. Moderately ill patients may also benefit from the administration of a serotonin antagonist (e.g., cyproheptadine, chlorpromazine). Severe cases should be managed under consultation with a toxicologist and may require sedation, neuromuscular paralysis, intubation, and mechanical ventilation in addition to the other measures.
ibuprofen ⇔ fluoxetine

Applies to:Motrin (ibuprofen), Prozac (fluoxetine)

Moderate Drug Interaction

MONITOR: Serotonin reuptake inhibitors (SRIs) may potentiate the risk of bleeding in patients treated with agents that affect hemostasis such as anticoagulants, platelet inhibitors, thrombin inhibitors, thrombolytic agents, or agents that commonly cause thrombocytopenia. The tricyclic antidepressant, clomipramine, is also a strong SRI and may interact similarly. Serotonin release by platelets plays an important role in hemostasis, thus SRIs may alter platelet function and induce bleeding. Published case reports have documented the occurrence of bleeding episodes in patients treated with psychotropic agents that interfere with serotonin reuptake. Additional epidemiological studies have confirmed the association between use of these agents and the occurrence of upper gastrointestinal bleeding, and concurrent use of NSAIDs or aspirin was found to potentiate the risk. Preliminary data also suggest that there may be a pharmacodynamic interaction between SSRIs and oral anticoagulants that can cause an increased bleeding diathesis. Concomitant administration of paroxetine and warfarin, specifically, has been associated with an increased frequency of bleeding without apparent changes in the disposition of either drug or changes in the prothrombin time. Bleeding has also been reported with fluoxetine and warfarin, while citalopram and sertraline have been reported to prolong the prothrombin time of patients taking warfarin by about 5% to 8%. MANAGEMENT: Caution is advised if SRIs or clomipramine are used in combination with other drugs that affect hemostasis. Close clinical and laboratory observation for hematologic complications is recommended. Patients should be advised to promptly report any signs of bleeding to their physician, including pain, swelling, headache, dizziness, weakness, prolonged bleeding from cuts, increased menstrual flow, vaginal bleeding, nosebleeds, bleeding of gums from brushing, unusual bleeding or bruising, red or brown urine, or red or black stools.
prednisone ⇔ bisoprolol

Applies to:prednisone, bisoprolol

Moderate Drug Interaction

MONITOR: Corticosteroids may antagonize the effects of antihypertensive medications by causing sodium and fluid retention. These effects may be more common with the natural corticosteroids (cortisone, hydrocortisone) because they have greater mineralocorticoid activity. In addition, some calcium channel blockers such as diltiazem and verapamil may increase corticosteroid plasma levels and effects by inhibiting their clearance via CYP450 3A4 metabolism. MANAGEMENT: Patients on prolonged (i.e., longer than about a week) or high-dose corticosteroid therapy should have blood pressure, electrolyte levels, and body weight monitored regularly, and be observed for the development of edema and congestive heart failure. The dosages of antihypertensive medications may require adjustment.
fludrocortisone ⇔ bisoprolol

Applies to:Florinef (fludrocortisone), bisoprolol

Moderate Drug Interaction

MONITOR: Corticosteroids may antagonize the effects of antihypertensive medications by causing sodium and fluid retention. These effects may be more common with the natural corticosteroids (cortisone, hydrocortisone) because they have greater mineralocorticoid activity. In addition, some calcium channel blockers such as diltiazem and verapamil may increase corticosteroid plasma levels and effects by inhibiting their clearance via CYP450 3A4 metabolism. MANAGEMENT: Patients on prolonged (i.e., longer than about a week) or high-dose corticosteroid therapy should have blood pressure, electrolyte levels, and body weight monitored regularly, and be observed for the development of edema and congestive heart failure. The dosages of antihypertensive medications may require adjustment.
bisoprolol ⇔ budesonide

Applies to:bisoprolol, Symbicort (budesonide/formoterol)

Moderate Drug Interaction

MONITOR: Corticosteroids may antagonize the effects of antihypertensive medications by causing sodium and fluid retention. These effects may be more common with the natural corticosteroids (cortisone, hydrocortisone) because they have greater mineralocorticoid activity. In addition, some calcium channel blockers such as diltiazem and verapamil may increase corticosteroid plasma levels and effects by inhibiting their clearance via CYP450 3A4 metabolism. MANAGEMENT: Patients on prolonged (i.e., longer than about a week) or high-dose corticosteroid therapy should have blood pressure, electrolyte levels, and body weight monitored regularly, and be observed for the development of edema and congestive heart failure. The dosages of antihypertensive medications may require adjustment.
theophylline ⇔ prednisone

Applies to:Theo-Dur (theophylline), prednisone

Moderate Drug Interaction

MONITOR: The concomitant use of theophylline and corticosteroids may theoretically increase the risk of hypokalemia due to additive potassium-lowering effects. Additionally, theophylline serum concentrations may be altered. The mechanism is unknown and data have been limited and conflicting; increased, decreased, and unchanged theophylline levels have all been reported. MANAGEMENT: Monitoring for altered efficacy and safety of theophylline and altered serum potassium and theophylline concentrations is advisable when these drugs are coadministered. Patients should be advised to notify their physician if they experience signs of hypokalemia (e.g., weakness, lethargy, and muscle pains or cramps), worsening respiratory symptoms, or signs of theophylline toxicity (e.g., nausea, vomiting, diarrhea, headache, restlessness, insomnia, or irregular heartbeat).
theophylline ⇔ fludrocortisone

Applies to:Theo-Dur (theophylline), Florinef (fludrocortisone)

Moderate Drug Interaction

MONITOR: The concomitant use of theophylline and corticosteroids may theoretically increase the risk of hypokalemia due to additive potassium-lowering effects. Additionally, theophylline serum concentrations may be altered. The mechanism is unknown and data have been limited and conflicting; increased, decreased, and unchanged theophylline levels have all been reported. MANAGEMENT: Monitoring for altered efficacy and safety of theophylline and altered serum potassium and theophylline concentrations is advisable when these drugs are coadministered. Patients should be advised to notify their physician if they experience signs of hypokalemia (e.g., weakness, lethargy, and muscle pains or cramps), worsening respiratory symptoms, or signs of theophylline toxicity (e.g., nausea, vomiting, diarrhea, headache, restlessness, insomnia, or irregular heartbeat).
theophylline ⇔ budesonide

Applies to:Theo-Dur (theophylline), Symbicort (budesonide/formoterol)

Moderate Drug Interaction

MONITOR: The concomitant use of theophylline and corticosteroids may theoretically increase the risk of hypokalemia due to additive potassium-lowering effects. Additionally, theophylline serum concentrations may be altered. The mechanism is unknown and data have been limited and conflicting; increased, decreased, and unchanged theophylline levels have all been reported. MANAGEMENT: Monitoring for altered efficacy and safety of theophylline and altered serum potassium and theophylline concentrations is advisable when these drugs are coadministered. Patients should be advised to notify their physician if they experience signs of hypokalemia (e.g., weakness, lethargy, and muscle pains or cramps), worsening respiratory symptoms, or signs of theophylline toxicity (e.g., nausea, vomiting, diarrhea, headache, restlessness, insomnia, or irregular heartbeat).
clonazepam ⇔ bisoprolol

Applies to:Klonopin (clonazepam), bisoprolol

Moderate Drug Interaction

MONITOR: Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation. Coadministration with antihypertensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis. MANAGEMENT: Caution is advised during coadministration of these agents. Close monitoring for development of hypotension is recommended. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.
fluoxetine ⇔ bisoprolol

Applies to:Prozac (fluoxetine), bisoprolol

Moderate Drug Interaction

MONITOR: Many psychotherapeutic and CNS-active agents (e.g., anxiolytics, sedatives, hypnotics, antidepressants, antipsychotics, opioids, alcohol, muscle relaxants) exhibit hypotensive effects, especially during initiation of therapy and dose escalation. Coadministration with antihypertensive agents, in particular vasodilators and alpha-blockers, may result in additive effects on blood pressure and orthostasis. MANAGEMENT: Caution is advised during coadministration of these agents. Close monitoring for development of hypotension is recommended. Patients should be advised to avoid rising abruptly from a sitting or recumbent position and to notify their physician if they experience dizziness, lightheadedness, syncope, orthostasis, or tachycardia.
carbamazepine ⇔ ondansetron

Applies to:Tegretol (carbamazepine), Zofran (ondansetron)

Moderate Drug Interaction

MONITOR: Concomitant use of CYP450 3A4 inducers with ondansetron may result in a reduced antiemetic effect, particularly after the oral administration of ondansetron. The proposed mechanism is induction of the CYP450 3A4 mediated metabolism of ondansetron. The clinical significance is unknown. MANAGEMENT: Patients should be monitored for reduced antiemetic effects and the ondansetron dose adjusted as necessary.
phenytoin ⇔ ondansetron

Applies to:Dilantin (phenytoin), Zofran (ondansetron)

Moderate Drug Interaction

MONITOR: Concomitant use of CYP450 3A4 inducers with ondansetron may result in a reduced antiemetic effect, particularly after the oral administration of ondansetron. The proposed mechanism is induction of the CYP450 3A4 mediated metabolism of ondansetron. The clinical significance is unknown. MANAGEMENT: Patients should be monitored for reduced antiemetic effects and the ondansetron dose adjusted as necessary.
albuterol ⇔ ondansetron

Applies to:ProAir HFA (albuterol), Zofran (ondansetron)

Moderate Drug Interaction

MONITOR: Beta-2 adrenergic agonists can cause dose-related prolongation of the QT interval and potassium loss. Theoretically, coadministration with other agents that can prolong the QT interval may result in elevated risk of ventricular arrhythmias, including ventricular tachycardia and torsade de pointes, because of additive arrhythmogenic potential related to their effects on cardiac conduction. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s). Clinically significant prolongation of QT interval and hypokalemia occur infrequently when beta-2 adrenergic agonists are inhaled at normally recommended dosages. However, these effects may be more common when the drugs are administered systemically or when recommended dosages are exceeded. MANAGEMENT: Caution is advised if beta-2 adrenergic agonists are used in combination with other drugs that prolong the QT interval, including class IA and III antiarrhythmic agents, certain neuroleptic agents, phenothiazines, tricyclic antidepressants, quinolones, ketolide and macrolide antibiotics, and cisapride. Patients should be advised to seek medical attention if they experience symptoms that could indicate the occurrence of torsades de pointes such as dizziness, palpitations, or syncope.
ondansetron ⇔ formoterol

Applies to:Zofran (ondansetron), Symbicort (budesonide/formoterol)

Moderate Drug Interaction

MONITOR: Beta-2 adrenergic agonists can cause dose-related prolongation of the QT interval and potassium loss. Theoretically, coadministration with other agents that can prolong the QT interval may result in elevated risk of ventricular arrhythmias, including ventricular tachycardia and torsade de pointes, because of additive arrhythmogenic potential related to their effects on cardiac conduction. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). In addition, the extent of drug-induced QT prolongation is dependent on the particular drug(s) involved and dosage(s) of the drug(s). Clinically significant prolongation of QT interval and hypokalemia occur infrequently when beta-2 adrenergic agonists are inhaled at normally recommended dosages. However, these effects may be more common when the drugs are administered systemically or when recommended dosages are exceeded. MANAGEMENT: Caution is advised if beta-2 adrenergic agonists are used in combination with other drugs that prolong the QT interval, including class IA and III antiarrhythmic agents, certain neuroleptic agents, phenothiazines, tricyclic antidepressants, quinolones, ketolide and macrolide antibiotics, and cisapride. Patients should be advised to seek medical attention if they experience symptoms that could indicate the occurrence of torsades de pointes such as dizziness, palpitations, or syncope.
carbamazepine ⇔ cetirizine

Applies to:Tegretol (carbamazepine), Zyrtec (cetirizine)

Moderate Drug Interaction

MONITOR: Concurrent use of cetirizine or levocetirizine with alcohol or other central nervous system (CNS) depressants may result in additive impairment of mental alertness and performance. Several studies have shown no effect of racemic cetirizine on cognitive function, motor performance, or sleep latency as indicated by objective measurements. However, there have been reports of somnolence, fatigue, and asthenia in some patients treated with cetirizine or levocetirizine in clinical trials. MANAGEMENT: Concomitant use of cetirizine or levocetirizine with alcohol or other CNS depressants should generally be avoided if possible. In the event that they are used together, patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
phenytoin ⇔ cetirizine

Applies to:Dilantin (phenytoin), Zyrtec (cetirizine)

Moderate Drug Interaction

MONITOR: Concurrent use of cetirizine or levocetirizine with alcohol or other central nervous system (CNS) depressants may result in additive impairment of mental alertness and performance. Several studies have shown no effect of racemic cetirizine on cognitive function, motor performance, or sleep latency as indicated by objective measurements. However, there have been reports of somnolence, fatigue, and asthenia in some patients treated with cetirizine or levocetirizine in clinical trials. MANAGEMENT: Concomitant use of cetirizine or levocetirizine with alcohol or other CNS depressants should generally be avoided if possible. In the event that they are used together, patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
clonazepam ⇔ cetirizine

Applies to:Klonopin (clonazepam), Zyrtec (cetirizine)

Moderate Drug Interaction

MONITOR: Concurrent use of cetirizine or levocetirizine with alcohol or other central nervous system (CNS) depressants may result in additive impairment of mental alertness and performance. Several studies have shown no effect of racemic cetirizine on cognitive function, motor performance, or sleep latency as indicated by objective measurements. However, there have been reports of somnolence, fatigue, and asthenia in some patients treated with cetirizine or levocetirizine in clinical trials. MANAGEMENT: Concomitant use of cetirizine or levocetirizine with alcohol or other CNS depressants should generally be avoided if possible. In the event that they are used together, patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
fluoxetine ⇔ cetirizine

Applies to:Prozac (fluoxetine), Zyrtec (cetirizine)

Moderate Drug Interaction

MONITOR: Concurrent use of cetirizine or levocetirizine with alcohol or other central nervous system (CNS) depressants may result in additive impairment of mental alertness and performance. Several studies have shown no effect of racemic cetirizine on cognitive function, motor performance, or sleep latency as indicated by objective measurements. However, there have been reports of somnolence, fatigue, and asthenia in some patients treated with cetirizine or levocetirizine in clinical trials. MANAGEMENT: Concomitant use of cetirizine or levocetirizine with alcohol or other CNS depressants should generally be avoided if possible. In the event that they are used together, patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
metoclopramide ⇔ cetirizine

Applies to:Reglan (metoclopramide), Zyrtec (cetirizine)

Moderate Drug Interaction

MONITOR: Concurrent use of cetirizine or levocetirizine with alcohol or other central nervous system (CNS) depressants may result in additive impairment of mental alertness and performance. Several studies have shown no effect of racemic cetirizine on cognitive function, motor performance, or sleep latency as indicated by objective measurements. However, there have been reports of somnolence, fatigue, and asthenia in some patients treated with cetirizine or levocetirizine in clinical trials. MANAGEMENT: Concomitant use of cetirizine or levocetirizine with alcohol or other CNS depressants should generally be avoided if possible. In the event that they are used together, patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
cetirizine ⇔ zonisamide

Applies to:Zyrtec (cetirizine), Zonegran (zonisamide)

Moderate Drug Interaction

MONITOR: Concurrent use of cetirizine or levocetirizine with alcohol or other central nervous system (CNS) depressants may result in additive impairment of mental alertness and performance. Several studies have shown no effect of racemic cetirizine on cognitive function, motor performance, or sleep latency as indicated by objective measurements. However, there have been reports of somnolence, fatigue, and asthenia in some patients treated with cetirizine or levocetirizine in clinical trials. MANAGEMENT: Concomitant use of cetirizine or levocetirizine with alcohol or other CNS depressants should generally be avoided if possible. In the event that they are used together, patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.
bisoprolol ⇔ albuterol

Applies to:bisoprolol, ProAir HFA (albuterol)

Moderate Drug Interaction

GENERALLY AVOID: Although cardioselective beta-blockers do not generally inhibit the bronchodilating effect of beta-2 adrenergic agonists, they may worsen pulmonary function in patients with asthma or other obstructive airway diseases. Cardioselective beta-blockers can occasionally precipitate acute bronchospasm in these patients, despite relative selectivity for beta-1 receptors in cardiac tissues. Presumably, beta-1 selectivity is dose-dependent and may be lost given a sufficient dose of the beta-blocker in susceptible patients. Other mechanisms may also be involved in bronchoconstriction that are unrelated to beta-2 blockade--for example, their effects on cholinergic M2 receptors and alpha-1 adrenoreceptors. Numerous single- and multiple-dose studies have been conducted in asthmatic and COPD patients with various cardioselective beta-blockers, including acebutolol, atenolol, bisoprolol, celiprolol, metoprolol, and nebivolol. Some reported no significant effects on pulmonary function or bronchodilator response to beta-2 adrenergic agonists, while others reported some negative effects on pulmonary function and/or airway hyperresponsiveness. Overall, a meta-analysis of more than two dozen studies found that use of cardioselective beta-blockers in patients with mild to moderate reversible airway disease produced no adverse respiratory effects or decreased responsiveness to beta-2 agonists in the short term. A meta-analysis of 19 studies conducted in patients with COPD by the same group of investigators reported similar results. However, little data exist regarding their safety during chronic use or use in patients with severe respiratory disease. There have been reports of worsening asthma and bronchospasm in patients receiving cardioselective beta-blockers including betaxolol (both systemic and ophthalmic) and esmolol. Several studies have suggested enhanced bronchosparing effects of celiprolol over other cardioselective beta-blockers due to its partial beta-2 agonistic and alpha-2 blocking activities. However, one study found no difference between celiprolol and nebivolol. A few studies also suggested a lower degree of beta-1 selectivity for acebutolol compared to other cardioselective beta-blockers. The clinical significance is unknown. MANAGEMENT: Beta-blockers, including those with relative cardioselectivity, should generally be avoided in patients with bronchospastic diseases. However, given their demonstrated benefit in such conditions as heart failure, myocardial infarction, cardiac arrhythmias and hypertension, cardioselective beta-blockers may be administered with caution to those who do not respond to or tolerate alternative treatment. The benefits generally outweigh the risks in patients with mild or moderate reactive airway disease that is well-controlled on inhaled corticosteroids and beta-2 adrenergic agonists, provided they have no prior history suggesting a predisposition to severe exacerbations. The dosage should start low, preferably in divided doses to avoid the higher plasma levels associated with longer dosing intervals, and titrated slowly according to therapeutic response and pulmonary function. Patients should be advised to contact their physician if they experience worsening of respiratory symptoms, which would warrant a reevaluation of the appropriateness of beta-blocker therapy. Cardioselective beta-blockers should be used with extreme caution, if at all, in patients prone to frequent exacerbations of their respiratory disease.
bisoprolol ⇔ formoterol

Applies to:bisoprolol, Symbicort (budesonide/formoterol)

Moderate Drug Interaction

GENERALLY AVOID: Although cardioselective beta-blockers do not generally inhibit the bronchodilating effect of beta-2 adrenergic agonists, they may worsen pulmonary function in patients with asthma or other obstructive airway diseases. Cardioselective beta-blockers can occasionally precipitate acute bronchospasm in these patients, despite relative selectivity for beta-1 receptors in cardiac tissues. Presumably, beta-1 selectivity is dose-dependent and may be lost given a sufficient dose of the beta-blocker in susceptible patients. Other mechanisms may also be involved in bronchoconstriction that are unrelated to beta-2 blockade--for example, their effects on cholinergic M2 receptors and alpha-1 adrenoreceptors. Numerous single- and multiple-dose studies have been conducted in asthmatic and COPD patients with various cardioselective beta-blockers, including acebutolol, atenolol, bisoprolol, celiprolol, metoprolol, and nebivolol. Some reported no significant effects on pulmonary function or bronchodilator response to beta-2 adrenergic agonists, while others reported some negative effects on pulmonary function and/or airway hyperresponsiveness. Overall, a meta-analysis of more than two dozen studies found that use of cardioselective beta-blockers in patients with mild to moderate reversible airway disease produced no adverse respiratory effects or decreased responsiveness to beta-2 agonists in the short term. A meta-analysis of 19 studies conducted in patients with COPD by the same group of investigators reported similar results. However, little data exist regarding their safety during chronic use or use in patients with severe respiratory disease. There have been reports of worsening asthma and bronchospasm in patients receiving cardioselective beta-blockers including betaxolol (both systemic and ophthalmic) and esmolol. Several studies have suggested enhanced bronchosparing effects of celiprolol over other cardioselective beta-blockers due to its partial beta-2 agonistic and alpha-2 blocking activities. However, one study found no difference between celiprolol and nebivolol. A few studies also suggested a lower degree of beta-1 selectivity for acebutolol compared to other cardioselective beta-blockers. The clinical significance is unknown. MANAGEMENT: Beta-blockers, including those with relative cardioselectivity, should generally be avoided in patients with bronchospastic diseases. However, given their demonstrated benefit in such conditions as heart failure, myocardial infarction, cardiac arrhythmias and hypertension, cardioselective beta-blockers may be administered with caution to those who do not respond to or tolerate alternative treatment. The benefits generally outweigh the risks in patients with mild or moderate reactive airway disease that is well-controlled on inhaled corticosteroids and beta-2 adrenergic agonists, provided they have no prior history suggesting a predisposition to severe exacerbations. The dosage should start low, preferably in divided doses to avoid the higher plasma levels associated with longer dosing intervals, and titrated slowly according to therapeutic response and pulmonary function. Patients should be advised to contact their physician if they experience worsening of respiratory symptoms, which would warrant a reevaluation of the appropriateness of beta-blocker therapy. Cardioselective beta-blockers should be used with extreme caution, if at all, in patients prone to frequent exacerbations of their respiratory disease.
theophylline ⇔ clonazepam

Applies to:Theo-Dur (theophylline), Klonopin (clonazepam)

Minor Drug Interaction

Methylxanthines may antagonize the sedative effects of benzodiazepines. Aminophylline in particular has been demonstrated to attenuate the sedative effects of diazepam. The mechanism of this interaction may be related to competitive binding to intracerebral adenosine receptors. One study demonstrated that alprazolam serum concentrations were significantly lower in patients receiving chronic theophylline therapy than in patients not receiving theophylline. Clinical and laboratory monitoring is warranted if these agents are given concurrently. Patients receiving this combination should be monitored for adequate response to the benzodiazepine.
ibuprofen ⇔ phenytoin

Applies to:Motrin (ibuprofen), Dilantin (phenytoin)

Minor Drug Interaction

One case report has suggested that ibuprofen may cause phenytoin toxicity. However, data have been conflicting: one pharmacokinetic study did not demonstrate an effect and another study demonstrated that ibuprofen displaces phenytoin from protein binding sites in vitro. The clinical significance is unknown. Clinical and laboratory monitoring for altered phenytoin effect is recommended.
phenytoin ⇔ methylphenidate

Applies to:Dilantin (phenytoin), Concerta (methylphenidate)

Minor Drug Interaction

According to the manufacturer, methylphenidate may inhibit the metabolism of anticonvulsants including phenobarbital, phenytoin, and primidone. There have been only isolated case reports of phenytoin intoxication during coadministration with methylphenidate and none for the other anticonvulsants. Moreover, two studies found little or no effect of methylphenidate on plasma phenytoin concentrations. Thus, available evidence does not seem to support a clinically significant drug interaction. Nevertheless, it may be appropriate to monitor the pharmacologic response to these anticonvulsants more closely whenever methylphenidate (racemic) or dexmethylphenidate (the more pharmacologically active d-enantiomer) is added to or withdrawn from therapy, and the anticonvulsant dosage adjusted as necessary.
fluoxetine ⇔ ondansetron

Applies to:Prozac (fluoxetine), Zofran (ondansetron)

Minor Drug Interaction

According to one case report, the addition of ondansetron to the regimen of a woman whose depression was being controlled with fluoxetine led to a brief episode of depressive symptoms. The mechanism may be decreased serotonergic transmission. Patients who are receiving these two agents concurrently should be observed for decreased antidepressant effect.
theophylline ⇔ cetirizine

Applies to:Theo-Dur (theophylline), Zyrtec (cetirizine)

Minor Drug Interaction

Coadministration with theophylline may decrease the clearance of cetirizine. The mechanism of interaction is unknown. According to the product labeling, a small decrease in the clearance of cetirizine was observed when given with a 400 mg dose of theophylline, and it is possible that larger theophylline doses could have a greater effect. No clinically significant drug interaction has been found with theophylline at a low dose. Steady-state cetirizine (10 mg twice daily for 3.5 days) has also been found to have no significant effects on the pharmacokinetics of theophylline (240 mg intravenously one hour after the last dose of cetirizine) in six healthy volunteers compared to placebo, and vice versa.

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389974 tn?1331018842
by swampcritter, Aug 20, 2009
Medhelp also has a drug interaction checker: http://www.medhelp.org/druginteractions



Avatar universal
by gfb50, Jan 10, 2011
When one has a problem with meds and one doctor gives you allergy meds another anti-depressant and an allergist gives you meds (many types of breathing treaments) and then the neurologist gives you meds for essential tremors and you get severe tremors and no one checks the interactions of all these meds , what or who is a patient to speak to to get this resolved!

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