United Kingdom (Great Britain)
A 18-year-old male asked:
How long would it take for 100mg of diphenhydramine hydrochloride to sedate a 55kg male?
2 doctor answers • 3 doctors weighed in
Family Medicine 23 years experience
Rapid absorption: Commonly known as benadryl, (diphenhydramine) and otc med, is very well absorbed and can start having an effect as early as 15 minutes. I would say that by 30 min, you would likely feel the sedative effect, if it works on you. It will last about 4-6 hours. Likely all med, use the smallest effective dose for shortest time possible. Consult doc. Good luck.
4.5k viewsReviewed >2 years ago
Allergy and Immunology 57 years experience
If it works: It should start working between 60-90 minutes based on my own experience but the sedating effects vary from person to person with some not experiencing any significant drowsiness at all . Do note that the sedating effect usually decreases with daily use.
4.5k viewsAnswered >2 years ago
Last updated May 12, 2017
Connect with a U.S. board-certified doctor by text or video anytime, anywhere.
24/7 visits - just $39!
50% off with $15/month membership
Content on HealthTap (including answers) should not be used for medical advice, diagnosis, or treatment, and interactions on HealthTap do not create a doctor-patient relationship. Never disregard or delay professional medical advice in person because of anything on HealthTap. Call your doctor or 911 if you think you may have a medical emergency.