Benzhydramine

Diphenhydramine is an antihistamine mainly used to treat allergies. It is also used for insomnia, symptoms of the common cold, tremor in parkinsonism, and nausea. It is used by mouth, injection into a vein, and injection into a muscle. Maximal effect is typically around two hours after a dose, and effects can last for up to seven hours. Diphenhydramine is an antihistamine mainly used to treat allergies. It is also used for insomnia, symptoms of the common cold, tremor in parkinsonism, and nausea. It is used by mouth, injection into a vein, and injection into a muscle. Maximal effect is typically around two hours after a dose, and effects can last for up to seven hours. Common side effects include sleepiness, poor coordination, and an upset stomach. Its use is not recommended in young children or the elderly. There is no clear risk of harm when used during pregnancy; however, use during breastfeeding is not recommended. It is a first generation H1-antihistamine and works by blocking certain effects of histamine. Diphenhydramine is also an anticholinergic. Diphenhydramine was first made by George Rieveschl and came into commercial use in 1946. It is available as a generic medication. The wholesale price in the developing world as of 2014 is about US$0.01 per dose. In the United States, it costs less than US$25 for a typical month’s supply. It is sold under the trade name Benadryl, among others. In 2016 it was the 210th most prescribed medication in the United States with more than 2 million prescriptions. Diphenhydramine is a first-generation antihistamine used to treat a number of conditions including allergic symptoms and itchiness, the common cold, insomnia, motion sickness, and extrapyramidal symptoms. Diphenhydramine also has local anesthetic properties, and has been used as such in people allergic to common local anesthetics such as lidocaine. 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. Its use for this purpose had not been properly studied as of 2007. 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. Diphenhydramine is used to treat Parkinson's disease–like extrapyramidal symptoms caused by antipsychotics. 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 can cause sedation and has also been used as an anxiolytic.