DIPHENHYDRAMINE - INJECTION
Common Brand Name(s): Benadryl
Phonetic Pronunciation: (dye-fen-HI-druh-meen)
Information last revised October 2010
What does DIPHENHYDRAMINE-INJ look like?
Diphenhydramine Min-I-Jet 50 mg/mL Syringe
diphenhydramine 50 mg/mL Injection
Diphenhydramine Min-I-Jet 50 mg/mL Syringe
diphenhydramine 50 mg/mL Injection
Benadryl 50 mg/mL Injection
diphenhydramine 50 mg/mL Injection
Uses:
Diphenhydramine injection is an antihistamine used to treat life-threatening allergic reactions (anaphylaxis) along with epinephrine and other treatments. It is also used to relieve symptoms of household allergies, hay fever and the common cold when medication cannot be given by mouth. Common allergy symptoms relieved by antihistamines include rash, itching, watery eyes, itchy eyes/nose/throat, cough, runny nose and sneezing. It is also used to treat nausea, vomiting and dizziness caused by motion sickness when medication cannot be given by mouth. Diphenhydramine works by blocking a certain natural substance (histamine) that your body makes during an allergic reaction. Its drying effects on such symptoms as watery eyes and runny nose are caused by blocking another natural substance made by your body (acetylcholine). Diphenhydramine should not be used in newborns or premature infants because of an increased risk of side effects.
Missed Dose
If you miss a dose, use it as soon you remember. If it is near the time of your next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.
How To Use
This medication is injected into a vein (IV) no faster than 25 milligrams per minute, or deeply into a muscle as directed by your doctor. Be very careful to inject into a vein or muscle and not into the skin or just under the skin. If this medication is injected into or just under the skin, it can destroy the skin and tissues around the injection site (necrosis). If you are giving this injection to yourself, be sure you learn the proper technique for injecting this drug. Before injecting each dose, clean the injection site with rubbing alcohol. Before using, check this product visually for particles or discoloration. If either is present, do not use the liquid. Follow your doctor's directions carefully. Learn how to store and discard needles and medical supplies safely. Consult your pharmacist. Do not use this medication more often than prescribed. Your dosage is based on your medical condition and response to therapy. Inform your doctor if your condition does not improve or if it worsens.
Drug Interactions
Your healthcare professionals (e.g., doctor or pharmacist) may already be aware of any possible drug interactions and may be monitoring you for it. Do not start, stop or change the dosage of any medicine before checking with them first. Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: antihistamines applied to the skin (such as diphenhydramine cream, ointment, spray), antispasmodics (e.g., atropine, belladonna alkaloids), drugs for Parkinson's disease (e.g., anticholinergics such as benztropine, trihexyphenidyl), MAO inhibitors (e.g., furazolidone, isocarboxazid, linezolid, moclobemide, phenelzine, procarbazine, rasagiline, selegiline, tranylcypromine), tricyclic antidepressants (e.g., amitriptyline). Tell your doctor or pharmacist if you also take drugs that cause drowsiness such as: certain antihistamines (e.g., dimenhydrinate), anti-seizure drugs (e.g., carbamazepine), medicine for sleep or anxiety (e.g., alprazolam, diazepam, zolpidem), muscle relaxants, narcotic pain relievers (e.g., codeine), psychiatric medicines (e.g., chlorpromazine, risperidone, amitriptyline, trazodone). Check the labels on all your medicines (e.g., cough-and-cold products) because they may contain drowsiness-causing ingredients. Ask your pharmacist about the safe use of those products. This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.
Notes
Do not take for several days before allergy testing. Test results can be affected. Do not share this medication with others.
Overdose
If overdose is suspected, contact your local poison control center or emergency room immediately. US residents can call the US national poison hotline at 1-800-222-1222. Canadian residents should call their local poison control center directly. Symptoms of overdose may include large pupils, flushing, fever, hallucinations, weakness, shaking (tremor), muscle twitching, loss of consciousness, and seizures. In children, excitement may occur first, and may be followed by loss of coordination, drowsiness, loss of consciousness, and seizures.
Precautions
Before using diphenhydramine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (e.g., asthma, emphysema), glaucoma, heart problems, high blood pressure, liver disease, mental/mood disorders, seizures, stomach problems (e.g., ulcers, obstruction), overactive thyroid, difficulty urinating (e.g., enlarged prostate, urinary retention). This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Limit the use of alcohol and certain other medications that cause drowsiness. (See also Drug Interactions.) To minimize dizziness and lightheadedness, get up slowly when rising from a seated or lying position. Caution is advised when using this drug in children because they are more sensitive to the effects of antihistamines. This drug can often cause excitement in young children instead of drowsiness. Caution is advised when using this drug in the elderly because they may be more sensitive to its effects, especially dizziness, drowsiness and low blood pressure. This medication should be used only when clearly needed during pregnancy. Tell your doctor if you are pregnant before using this medication. This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.
Storage
Store at room temperature between 59-86 degrees F (between 15-30 degrees C) away from moisture and light. Do not store in the bathroom. Do not freeze. Keep all medicines away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.
Side Effects
Drowsiness, dizziness, headache, irritability, stomach upset, vision changes (e.g., blurred vision), decreased coordination, or dry mouth/nose/throat may occur. These effects may decrease as your body adjusts to the medication. If they persist or become bothersome, inform your doctor. To relieve dry mouth, suck on (sugarless) hard candy or ice chips, chew (sugarless) gum, drink water or use a saliva substitute. Diphenhydramine can dry up and thicken the mucus in your lungs, making it more difficult to breathe and clear your lungs. To help prevent this effect, be sure to drink plenty of fluids unless otherwise directed by your physician. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor immediately if any of these rare but serious side effects occur: pounding/irregular heartbeat, ringing in the ears, seizure, difficulty urinating. A very serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction may include: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Other Uses
This section contains uses of this drug that are not listed in the approved professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional. Diphenhydramine injection is also used alone or with other medications to treat shaking (tremor) and muscle stiffness caused by Parkinson's disease when medication cannot be given by mouth. It may also be used to treat side effects of certain psychiatric drugs such as involuntary movements and muscle stiffness (e.g., EPS). It works by blocking acetylcholine. (See also Uses section.)