Diphenhydramine is an antihistamine mainly used to treat allergies.[8] It can also be used for insomnia, symptoms of the common cold, tremor in parkinsonism, and nausea.[8] It is used by mouth, injection into a vein, injection into a muscle, or applied to the skin.[8] Maximal effect is typically around two hours after a dose, and effects can last for up to seven hours.[8]
Common side effects include sleepiness, poor coordination ...
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