Diphenhydramine is deemed to have limited abuse potential in the United States owing to its potentially serious side-effect profile and limited euphoric effects, and is not a controlled substance. and travelers are advised not to bring the drug into the country.Several Americans have been detained by the Zambian Drug Enforcement Commission for possession of Benadryl and other over-the-counter medications containing diphenhydramine.Acyclovir is an antiviral agent that acts by inhibiting herpes virus DNA polymerase and terminating viral replication.It reduces the number of lesions and duration of fever if it is started within 24 hours of rash appearance.The utility of diphenhydramine as an antiparkinson agent is the result of its blocking properties on the muscarinic acetylcholine receptors in the brain.Diphenhydramine also acts as an intracellular sodium channel blocker, which is responsible for its actions as a local anesthetic.
The selective serotonin reuptake inhibitor (SSRI) antidepressant fluoxetine is also a close analogue of diphenhydramine.
Other side effects include motor impairment (ataxia), flushed skin, blurred vision at nearpoint owing to lack of accommodation (cycloplegia), abnormal sensitivity to bright light (photophobia), sedation, difficulty concentrating, short-term memory loss, visual disturbances, irregular breathing, dizziness, irritability, itchy skin, confusion, increased body temperature (in general, in the hands and/or feet), temporary erectile dysfunction, and excitability, and although it can be used to treat nausea, higher doses may cause vomiting.
As diphenhydramine is extensively metabolized by the liver, caution should be exercised when giving the drug to individuals with hepatic impairment.
Diphenhydramine is marketed under the trade name Benadryl by Mc Neil Consumer Healthcare in the U. Trade names in other countries include Dimedrol, Daedalon, and Nytol. Procter & Gamble markets an over-the-counter formulation of diphenhydramine as a sleep aid under the brand Zzz Quil.
In 2014 this product had annual sales of over 0 million and had a 29.3% share of the 1 million sleep-aid market category.