This has been met with criticism, both by doctors and members of the airline industry, as sedating young passengers may put them at risk if the flight encounters an emergency and they are unable to react to the situation efficiently, and the drugs side effects, especially the chance of a paradoxical reaction, may result in some individuals becoming hyperactive rather than sedated. The ethics of this use have also been challenged, with the Seattle Childrens hospital arguing in a 2009 article that "Using a medication for your convenience is never an indication for medication in a child. "The American Academy of Sleep Medicines 2017 clinical practice guidelines recommended against the use of diphenhydramine in the treatment of insomnia due to poor effectiveness and low quality of evidence. A major systematic review and network meta-analysis of medications for the treatment of insomnia published in 2022 found little evidence to inform the use of diphenhydramine for insomnia. Nausea
Diphenhydramine also has antiemetic properties, which make it useful in treating the nausea that occurs in vertigo and motion sickness. Special populations
Diphenhydramine is not recommended for people older than 60 or children under the age of six, unless a physician is consulted. These populations should be treated with second-generation antihistamines such as loratadine, desloratadine, fexofenadine, cetirizine, levocetirizine, and azelastine. Due to its strong anticholinergic effects, diphenhydramine is on the Beers list of drugs to avoid in the elderly.Diphenhydramine is category B in the FDA Classification of Drug Safety During Pregnancy. It is also excreted in breast milk.
Allergies
Diphenhydramine is effective in treatment of allergies. As of 2007, it was the most commonly used antihistamine for acute allergic reactions in the emergency department.By injection it is often used in addition to epinephrine for anaphylaxis, although as of 2007 its use for this purpose had not been properly studied. Its use is only recommended once acute symptoms have improved. Topical formulations of diphenhydramine are available, including creams, lotions, gels, and sprays. These are used to relieve itching and have the advantage of causing fewer systemic effects (e.g., drowsiness) than oral forms. Movement disorders
Diphenhydramine is used to treat akathisia and Parkinsons disease–like extrapyramidal symptoms caused by antipsychotics. It is also used to treat acute dystonia including torticollis and oculogyric crisis caused by first generation antipsychotics. Sleep
Because of its sedative properties, diphenhydramine is widely used in nonprescription sleep aids for insomnia. The drug is an ingredient in several products sold as sleep aids, either alone or in combination with other ingredients such as acetaminophen (paracetamol) in Tylenol PM or ibuprofen in Advil PM. Diphenhydramine can cause minor psychological dependence. Diphenhydramine has also been used as an anxiolytic.Diphenhydramine has also been used off prescription by parents in an attempt to make their children sleep or remain sedated on long-distance flights.