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Diphenhydramine Hydrochloride Solution for injection

What is this medicine?

DIPHENHYDRAMINE (dye fen HYE dra meen) is an antihistamine. It is used to treat the symptoms of an allergic reaction and motion sickness. It is also used to treat Parkinson's disease.

How should I use this medicine?

This medicine is for injection into a vein or a muscle. It is usually given by a health care professional in a hospital or clinic setting.

If you get this medicine at home, you will be taught how to prepare and give this medicine. Use exactly as directed. Take your medicine at regular intervals. Do not take your medicine more often than directed.

It is important that you put your used needles and syringes in a special sharps container. Do not put them in a trash can. If you do not have a sharps container, call your pharmacist or healthcare provider to get one.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for selected conditions, precautions do apply. This medicine is not approved for use in newborns and premature babies.

Patients over 60 years old may have a stronger reaction and need a smaller dose.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:

  • allergic reactions like skin rash, itching or hives, swelling of the face, lips, or tongue

  • breathing problems

  • changes in vision

  • chills

  • confused, agitated, nervous

  • irregular or fast heartbeat

  • low blood pressure

  • seizures

  • tremor

  • trouble passing urine

  • unusual bleeding or bruising

  • unusually weak or tired

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • constipation, diarrhea

  • drowsy

  • headache

  • loss of appetite

  • stomach upset, vomiting

  • sweating

  • thick mucous

What may interact with this medicine?

Do not take this medicine with any of the following medications:

  • MAOIs like Carbex, Eldepryl, Marplan, Nardil, and Parnate

This medicine may also interact with the following medications:

  • alcohol

  • barbiturates, like phenobarbital

  • medicines for bladder spasm like oxybutynin, tolterodine

  • medicines for blood pressure

  • medicines for depression, anxiety, or psychotic disturbances

  • medicines for movement abnormalities or Parkinson's disease

  • medicines for sleep

  • other medicines for cold, cough or allergy

  • some medicines for the stomach like chlordiazepoxide, dicyclomine

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

Where should I keep my medicine?

Keep out of the reach of children.

If you are using this medicine at home, you will be instructed on how to store this medicine. Throw away any unused medicine after the expiration date on the label.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:

  • asthma or lung disease

  • glaucoma

  • high blood pressure or heart disease

  • liver disease

  • pain or difficulty passing urine

  • prostate trouble

  • ulcers or other stomach problems

  • an unusual or allergic reaction to diphenhydramine, antihistamines, other medicines foods, dyes, or preservatives

  • pregnant or trying to get pregnant

  • breast-feeding

What should I watch for while using this medicine?

Your condition will be monitored carefully while you are receiving this medicine. Tell your doctor or healthcare professional if your symptoms do not start to get better or if they get worse.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water may help. Contact your doctor if the problem does not go away or is severe.

Online Medical Reviewer: Louise Akin, RN, BSN
Online Medical Reviewer: Daphne Pierce-Smith, RN, MSN, FNP, CCRC
Last Review Date: 4/7/2009
© 2000-2014 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.