Medical Editor: John P. Cunha, DO, FACOEP
What Is Benadryl Injection?
Benadryl Injection (diphenhydramine hydrochloride) is an antihistamine used to treat life-threatening allergic reactions (anaphylaxis) along with epinephrine and other treatments. Benadryl Injection is also used to relieve symptoms of household allergies, hay fever and the common cold when medication cannot be given by mouth. Benadryl Injection is also used to treat nausea, vomiting and dizziness caused by motion sickness when medication cannot be given by mouth. The brand name of Benadryl Injection is discontinued, but generic versions may be available.
What Are Side Effects of Benadryl Injection?
Common side effects of Benadryl Injection (diphenhydramine hydrochloride) include:
- stomach upset,
- vision changes (e.g., blurred vision),
- decreased coordination, or
- dry mouth/nose/throat.
Tell your doctor right away if you have any serious side effects of Benadryl Injection including mental/mood changes (such as restlessness, confusion), pounding or irregular heartbeat, ringing in the ears, seizures, or difficulty urinating.
Dosage for Benadryl Injection
The adult dose of Benadryl Injection is 10 to 50 mg intravenously at a rate generally not exceeding 25 mg/min, or deep intramuscularly, 100 mg if required; maximum daily dosage is 400 mg.
What Drugs, Substances, or Supplements Interact with Benadryl Injection?
Benadryl Injection may interact with antihistamines applied to the skin, antispasmodics, drugs for Parkinson's disease, MAO inhibitors, antidepressants, or drugs that cause drowsiness (such as antihistamines, anti-seizure drugs, medicine for sleep or anxiety, muscle relaxants, narcotics, or psychiatric medicines). Tell your doctor all medications and supplements you use.
Benadryl Injection During Pregnancy and Breastfeeding
During pregnancy, Benadryl Injection should be used only if prescribed. This drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breastfeeding.
Our Benadryl Injection (diphenhydramine hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
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 right away if you have any serious side effects, including: mental/mood changes (such as restlessness, confusion), pounding/irregular heartbeat, ringing in the ears, seizure, difficulty urinating.
A very serious allergic reaction to this drug is unlikely, but get medical help right away 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.
Read the entire patient information overview for Benadryl Injection (Diphenhydramine Injection)
The most frequent adverse reactions are underscored.
Nervous System: Sedation, sleepiness, dizziness, disturbed coordination, fatigue, confusion, restlessness, excitation, nervousness, tremor, irritability, insomnia, euphoria, paresthesia, blurred vision, diplopia, vertigo, tinnitus, acute labyrinthitis, neuritis, convulsions
Read the entire FDA prescribing information for Benadryl Injection (Diphenhydramine Injection)
© Benadryl Injection Patient Information is supplied by Cerner Multum, Inc. and Benadryl Injection Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.