Doxylamine, usually in the form of doxylamine
succinate, is an
anticholinergic antihistamine, similar to
diphenhydramine (
Benadryl). When sold alone, it is usually used as a
sleep aid (it is the active ingredient in
Unisom® and
Decapryn®). It is often combined with
DXM,
pseudoephedrine, and
acetaminophen in nightime cough and
cold medicines such as
NyQuil®. The standard dose is 25
mg, or half that for children under 6.
Caution should be used when combining doxylamine with the herb
henbane, which is also an anticholinergic, and with
alcohol, which can intensify its
sedative effects.