Antihistamines are Deadly

For those of you who might be under the impression that Benadryl or other antihistamines are handy sleep aides with no ill effects, I'd like to offer some input.

They are deadly in overdose, and overdosing is incredibly easy. One of the side-effects often ignored is short-term memory loss. Adults who live alone or already suffer from some dementia can readily continue to dose themselves to attempt to use it as a sleep aid only to overdose on an over-the-counter medication unintentionally. Anticholinergic syndrome can be the result, exacerbating any proclivity to seizure and causing an agitated psychosis which can cause a delay in seeking treatment.

They should never be used as sleep aids, especially in conjunction with benzodiazepines . Benzodiazepines, which include many anti-seizure and anti-anxiety medications, are also prescribed as sleep aids. Benzodiazepines already have a memory-interfering and hypnotic effect, so adding available over-the-counter antihistamines (diphenhydramine, otherwise known as "Benadryl") is a multiplier for fatal overdose on either medication, increasing the multiple effects of disinhibition, agitation, and short term memory loss.

To this end, I think that antihistamines should have a black-box warning or other information explicitly outlining the effects of overdose and the symptoms of toxicity, and the conjunction of benzodiazepines and antihistamines should be contraindicated (similar to SSRI and alcohol warnings).