diphenhydrAMINE (generic name)

Sominex (brand name)

It is used to treat the symptoms of an allergic reaction
(dye fen HYE dra meen)
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What is this medicine?

DIPHENHYDRAMINE (dye fen HYE dra meen) is an antihistamine. It is used to treat the symptoms of an allergic reaction.

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

They need to know if you have any of these conditions:
  • diabetes
  • glaucoma
  • high blood pressure or heart disease
  • liver disease
  • lung or breathing disease, like asthma
  • pain or trouble passing urine
  • phenylketonuria
  • prostate trouble
  • ulcers or other stomach problems
  • an unusual or allergic reaction to diphenhydramine, other medicines foods, dyes, or preservatives such as sulfites
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth. Follow the directions on the prescription label. Shake well before using. Use a specially marked spoon or container to measure your medicine. Household spoons are not accurate. Take your medicine at regular intervals. Do not take it more often than directed.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for children as young as 2 years old for selected conditions, precautions do apply.

Patients over 65 years old may have a stronger reaction and need a smaller dose.

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.

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 should I watch for while using this medicine?

Visit your doctor or health care professional for regular check ups. Tell your doctor or health care professional if your symptoms do not start to get better or if they get worse.

If you are diabetic use a sugar-free form of this medicine.

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.

This medicine may cause dry eyes and blurred vision. If you wear contact lenses you may feel some discomfort. Lubricating drops may help. See your eye doctor if the problem does not go away or is severe.

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.

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Last Updated: April 17, 2009
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