TREATMENT DATABASE

Benadryl (diphenhydramine) is an antihistamine. It is useful for treating hives, seasonal allergies, upper airway congestion, and severe allergic reactions (anaphylactic shock). Benadryl is an anticholinergic, meaning it blocks the effects of the neurotransmitter acetylcholine. Side effects can include dry mouth, muscle weakness, and "brain fog." The drug is very sedating.

USES IN ME/CFS: Benadryl can be used as a sleep aid for ME/CFS-related insomnia if taken at bedtime. Like other antihistamines, Benadryl is not addictive, and thus may offer a good alternative to habit-forming sleeping pills. However, as Dr. David Bell points out in The Doctor's Guide to Chronic Fatigue Syndrome, Benadryl can lose effectiveness with continuous use for longer than a few weeks and therefore may be better used only occasionally.

Some patients note that, although Benadryl ensures a good night's sleep, rotating it with a benzodiazepine prevents developing a tolerance to either drug. Although Benadryl is generally well tolerated, adverse reactions – notably agitation and tachycardia – have been reported. If you are taking other medications, it is important to check with your physician before trying Benadryl, especially if you are prone to heartbeat irregularities. 

Treatment rating for Benadryl (diphenhydramine)