Drug Interactions
See also Precautions section. The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring. To help your doctor and pharmacist give you the best care, be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor's approval. Some products that may interact with this drug include: Some products that may interact with this drug include: anticholinergic/antispasmodic medications (such as belladonna alkaloids, dicyclomine, scopolamine), certain antihypertensive medications (such as clonidine, guanabenz, methyldopa), other drugs that can cause bleeding/bruising (including antiplatelet drugs such as clopidogrel, NSAIDs such as ibuprofen, "blood thinners" such as warfarin), bronchodilators/decongestants/stimulants (such as albuterol, phenylephrine, amphetamines, methylphenidate), disulfiram, thyroid supplements, MAO inhibitors (furazolidone, isocarboxazid, linezolid, moclobemide, phenelzine, procarbazine, selegiline, tranylcypromine). Avoid taking MAO inhibitors within 2 weeks before, during, and after treatment with this medication. In some cases a serious (possibly fatal) drug interaction may occur. Other medications can affect the removal of perphenazine/amitriptyline from your body, which may affect how this medication works. Examples include cimetidine, azole antifungals (such as fluconazole, ketoconazole, itraconazole), drugs to treat irregular heartbeat (such as amiodarone, flecainide, propafenone, quinidine), macrolide antibiotics (such as erythromycin), rifamycins (such as rifabutin), anti-HIV drugs (such as amprenavir, fosamprenavir, ritonavir), SSRI antidepressants (such as fluoxetine, paroxetine), St. John's wort, among others. If you have been taking fluoxetine, wait at least 5 weeks after stopping fluoxetine before starting perphenazine/amitriptyline. Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine). Many drugs besides perphenazine/amitriptyline may affect the heart rhythm (QT prolongation). Examples include amiodarone, dofetilide, pimozide, procainamide, quinidine, sotalol, macrolide antibiotics (such as erythromycin), among others. Also report the use of drugs that might increase seizure risk when combined with this medication, such as bupropion, isoniazid (INH), phenothiazines (such as thioridazine), or theophylline among others. Consult your doctor or pharmacist for details. Before taking this medication, report the use of other drugs that increase serotonin, such as dextromethorphan, lithium, St. John's wort, sibutramine, street drugs such as MDMA/"ecstasy," tramadol, tryptophan, certain antidepressants including SSRIs (such as citalopram, paroxetine) and SNRIs (such as duloxetine, venlafaxine), "triptans" used to treat migraine headaches (such as eletriptan, sumatriptan), among others. The risk of serotonin syndrome may be more likely when you start or increase the dose of these medications. Check the labels on all your medicines (such as antacids, allergy, or cough-and-cold products) because they may contain cimetidine, decongestants, or ingredients that cause drowsiness. Ask your pharmacist about using those products safely. Aspirin can increase the risk of bleeding when used with this medication. However, if your doctor has directed you to take low-dose aspirin for heart attack or stroke prevention (usually at dosages of 81-325 milligrams a day), you should continue taking it unless your doctor instructs you otherwise. Ask your doctor or pharmacist for more details. This document does not contain all possible drug interactions. Keep a list of all the products you use. Share this list with your doctor and pharmacist to lessen your risk for serious medication problems.