@knotmyday I have to keep Benadryl on hand, because I am allergic to bee stings, but I avoid it otherwise precisely because it puts me to sleep!
According to this FDA report, looks like they are OK unless you have breathing problems:
“Used appropriately, OTC and prescription sleep-aids also can
help provide sounder sleep, the ASDA advises. The association
cautions, however, that for some types of insomnia, such as that
caused by breathing disorders, the products may be dangerous.
“Before taking any OTC drug product, you should read the label
for directions on how and when to use it, and whether you should
check with a doctor before taking it,” says FDA regulatory review
pharmacist Michael Benson. “Antihistamines are the ingredients in
OTC nighttime sleep-aids that make you nod off, and some contain
other ingredients, like an analgesic for pain,” he says.
FDA allows three antihistamines—diphenhydramine hydrochloride
(HCl), diphenhydramine citrate, and doxylamine succinate—to be
used as the active ingredient in OTC nighttime sleep-aids.
In the early 1970s, FDA began a review of OTC drug products.
Manufacturers were requested to submit data on the safety and
effectiveness of the active ingredients for their intended uses.
Expert panels on various classes of drug products were convened to
review the data and make recommendations to the agency.
In 1978, FDA approved a new drug application providing for OTC
marketing of doxylamine succinate for nighttime sleep-aid use. In
1982, the agency authorized the initial marketing of
diphenhydramine HCl and diphenhydramine citrate for this use. These
two drugs were the only ones included in the agency’s final
monograph on OTC nighttime sleep-aids, issued in 1989. After the
monograph’s publication, products containing active ingredients
other than doxylamine succinate, diphenhydramine HCl, or
diphenhydramine citrate had to be reformulated or taken off the
market.”