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Benadryl Injection Side Effects Center
Medical Editor: John P. Cunha, DO, FACOEP
Benadryl Injection (diphenhydramine hydrochloride) 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. It is also used to treat nausea, vomiting and dizziness caused by motion sickness when medication cannot be given by mouth. The brand name of this medication is discontinued, but generic versions may be available. Common side effects include drowsiness, dizziness, headache, irritability, stomach upset, vision changes (e.g., blurred vision), decreased coordination, or dry mouth/nose/throat.
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. 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. 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.
What is Patient Information Overview?
A concise overview of the drug for the patient or caregiver from First DataBank.
Benadryl Injection Overview - Patient Information: Side Effects
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)»
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Benadryl Injection FDA Prescribing Information: Side Effects
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) »
Additional Benadryl Injection Information
- Benadryl Injection Drug Interactions Center: diphenhydramine hcl inj
- Benadryl Injection Side Effects Center
- Benadryl Injection Overview including Precautions
- Benadryl Injection FDA Approved Prescribing Information including Dosage
Benadryl Injection - User Reviews
Benadryl Injection User Reviews
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.
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