Diphenhydramine (Benadryl)
25 mg
Stop: Call 911 or get emergency help
Fast-spreading hives can be serious. Hives AND breathing trouble/wheezing/tight throat or chest, lip/tongue/face/throat swelling, trouble swallowing/hoarse voice, fainting/racing heart, or vomiting/cramps/diarrhea: use epinephrine if available. Seek emergency care.
Seek medical help first
Use this information only if you are unable to contact your provider. Then, contact your provider as soon as possible.
What it may treat & how much to take
- 1
Hives — no other symptoms
Itchy raised red/pink welts; breathing normal.
Daytime: consider loratadine. Take 1–2 tablets every 4–6 hours as needed.
- 2
Itchy rash / bug bites / poison ivy
Itchy red bumps or streaky patches.
Take 1–2 tablets every 4–6 hours as needed. Can also use triamcinolone acetonide (see card).
- 3
Seasonal allergies
Sneezing; runny/stuffy nose; itchy watery eyes or throat; no fever.
Consider loratadine. Take 1–2 tablets only if needed or at bedtime.
- 4
Mild food / medicine reaction
Skin-only hives/itch after food or medicine.
Take 2 tablets now; then 1–2 tablets every 4–6 hours. Call 911 if emergency signs appear.
- 5
Motion sickness
Severe reaction already treated with epinephrine.
See meclizine card; do not take both. Take 1–2 tablets 30 minutes before travel.
- 6
Occasional trouble sleeping
Cannot fall asleep for a night or two.
Melatonin is first choice. Take 2 tablets at bedtime for only a few nights. Do not use age 65+.
How to take it
Take with or without food. Starts working in about 1 hour and lasts 4 to 6 hours. Use for the shortest time needed. Lock away from children; overdose can be deadly.
Important information
No driving or activities requiring alertness. Do not combine with meclizine, melatonin, sleep/anxiety pills, muscle relaxers, opioids, or other sleepy medicines unless a provider says. Do not combine with loratadine unless your provider has told you to use both.
Common side effects
Very sleepy; dry mouth/nose/throat; dizzy; blurred/double vision; unsteady; constipation; headache; next-day groggy.
Do not take if
You are allergic to Benadryl (diphenhydramine), take other medicines that make you drowsy, or take an MAO inhibitor. DO NOT take with alcohol.
Ask your provider or pharmacist first if
Age 65+; glaucoma; prostate/urine problems; asthma, emphysema, COPD; heart disease, high blood pressure, overactive thyroid; stomach ulcer/blockage; seizures; or taking other sleepy medicines.
If pregnant or breastfeeding
Ask a provider first. Use only if clearly needed. Breastfeeding may make baby sleepy/fussy or lower milk supply.