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What is it? Overview Usage Side Effects and Warnings

Diphenhydramine Overview

Written by FoundHealth.

(dye fen HYE dra meen)

U.S. Brand Names

Aler-Cap [OTC]; Aler-Dryl [OTC]; Aler-Tab [OTC]; AllerMax® [OTC]; Altaryl [OTC]; Anti-Hist [OTC]; Banophen™ Anti-Itch [OTC]; Banophen™ [OTC]; Ben-Tann [DSC]; Benadryl® Allergy Quick Dissolve [OTC]; Benadryl® Allergy [OTC]; Benadryl® Children's Allergy Fastmelt® [OTC]; Benadryl® Children's Allergy Perfect Measure™; Benadryl® Children's Allergy [OTC]; Benadryl® Children's Dye-Free Allergy [OTC]; Benadryl® Children’s Allergy Quick Dissolve [OTC] [DSC]; Benadryl® Dye-Free Allergy [OTC]; Benadryl® Itch Relief Extra Strength [OTC]; Benadryl® Itch Stopping Extra Strength [OTC]; Benadryl® Itch Stopping [OTC]; Compoz® Nighttime Sleep Aid [OTC]; Dermamycin® [OTC]; Diphen [OTC]; Diphenhist® [OTC]; Dytan™; Genahist™ [OTC]; Histaprin [OTC]; Hydramine [OTC]; Nytol® Quick Caps [OTC]; Nytol® Quick Gels [OTC]; PediaCare® Children’s Allergy [OTC]; PediaCare® Children’s NightTime Cough [OTC]; Siladryl Allergy [OTC]; Silphen Cough [OTC]; Simply Sleep™ [OTC]; Sleep-ettes D [OTC]; Sleep-Tabs [OTC]; Sleepinal® [OTC]; Sominex® Maximum Strength [OTC]; Sominex® [OTC]; Theraflu® Thin Strips® Multi Symptom [OTC]; Triaminic Thin Strips® Children's Cough and Runny Nose [OTC]; Twilite® [OTC]; Unisom® SleepGels® Maximum Strength [OTC]; Unisom® SleepMelts™ [OTC]

Canadian Brand Names

Allerdryl®; Allernix; Benadryl®; Nytol®; Nytol® Extra Strength; PMS-Diphenhydramine; Simply Sleep®

Mexican Brand Names

Benadryl; Brudifen; Drafen; Indumir; Therafilm; Vicnite

Pharmacologic Category

Histamine H1 Antagonist; Histamine H1 Antagonist, First Generation

What key warnings should I know about before taking this medicine?

• Talk with healthcare provider before giving this medicine to a child. Check all of your child's medicines, including over-the-counter, with healthcare provider.

Reasons not to take this medicine

• Do not give Benadryl® Children's Allergy Fastmelt® if your child is allergic to peanuts or soybeans.

• If you have an allergy to diphenhydramine or any other part of this medicine.

• Tell healthcare provider if you are allergic to any medicine. Make sure to tell about the allergy and how it affected you. This includes telling about rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other symptoms involved.

• If you have asthma.

• If you are breast-feeding.

How does it work?

• Diphenhydramine blocks the allergic reaction by minimizing or preventing the body's reaction to the allergen.

• It helps treat a chemical imbalance.

• It calms the brain.

• It affects the vomiting center in the brain.

How is it best taken?


• If you are taking this medicine for an allergy, it is most effective if started before contact with the allergen. Take at least 1-3 hours before.

• If you are taking this medicine for motion sickness, take 30 minutes before travel.

• If you are taking this medicine for a sleep disorder, take 1 hour before going to bed.

• Take this medicine with or without food. Take with food if it causes an upset stomach.

• A liquid (elixir, syrup) is available if you cannot swallow pills.

• Those who have feeding tubes can also use the liquid. Flush the feeding tube before and after medicine is given.

Oral-disintegrating tablet:Place on tongue and let dissolve. Water is not needed. Do not swallow whole. Do not chew, break, or crush.

• Chewable tablet: Chew or crush well. Mix crushed tablet with food. Do not swallow whole.


• Do not take this medicine by mouth. For skin only. Keep out of mouth, nose, and eyes (may burn).

• Wash hands before and after use.

• Clean affected area before use. Make sure to dry well.

• Apply a thin layer to the affected skin and rub in gently.


• This medicine is given as a shot into a muscle or vein.

What do I do if I miss a dose? (does not apply to patients in the hospital)

• Take a missed dose as soon as possible.

• If it is almost time for the next dose, skip the missed dose and return to your regular schedule.

• Do not take a double dose or extra doses.

• Many times this medicine is taken on an as needed basis.

What should I monitor?

• Change in condition being treated. Is it better, worse, or about the same?

• Dry mouth may cause an increase in cavities. Take good care of your teeth. See a dentist regularly.

How should I store this medicine?


• Store at room temperature.

• Protect capsules and tablets from moisture. Do not store in a bathroom or kitchen.


• This medicine will be given to you in a healthcare setting. You will not store it at home.

General statements

• If you have a life-threatening allergy, wear allergy identification at all times.

• Do not share your medicine with others and do not take anyone else's medicine.

• Keep all medicine out of the reach of children and pets.

• Most medicines can be thrown away in household trash after mixing with coffee grounds or kitty litter and sealing in a plastic bag.

• Keep a list of all your medicines (prescription, natural products, supplements, vitamins, over-the-counter) with you. Give this list to healthcare provider (doctor, nurse, nurse practitioner, pharmacist, physician assistant).

• Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or in Canada to Health Canada's Canada Vigilance Program at 1-866-234-2345.

• Talk with healthcare provider before starting any new medicine, including over-the-counter, natural products, or vitamins.

Created: 2006-10-13 12:01:53.0

Modified: 2010-04-07 11:33:00.0

Lexi-PALS TM © (1977)-(2007) Lexi-Comp, Inc. All rights reserved.



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