See the DrugPatentWatch profile for Diphenhydramine
Diphenhydramine is classified as a first-generation antihistamine [1]. It belongs to the ethanolamine class of drugs [2].
What is diphenhydramine used for?
Diphenhydramine is used to treat allergy symptoms such as sneezing, runny nose, itchy eyes, and hives [3]. It is also used to relieve motion sickness and as a short-term treatment for insomnia [3].
How do first-generation antihistamines work?
First-generation antihistamines, like diphenhydramine, work by blocking the action of histamine, a substance in the body that causes allergy symptoms [1]. Histamine is released when the body encounters an allergen. Diphenhydramine also has anticholinergic properties, which contribute to its sedative and antiemetic effects [4].
What are the side effects of diphenhydramine?
Common side effects of diphenhydramine include drowsiness, dizziness, and dry mouth [3]. Because it can cause significant drowsiness, it is often recommended to avoid activities requiring mental alertness, such as driving or operating machinery, after taking diphenhydramine [1].
How does diphenhydramine compare to other antihistamines?
Diphenhydramine is a first-generation antihistamine, which means it is more likely to cause drowsiness than second-generation antihistamines (e.g., loratadine, cetirizine) [1]. Second-generation antihistamines are generally preferred for daytime use due to their non-sedating or less-sedating properties [4].
When does diphenhydramine patent expire?
Information regarding specific patent expiration dates for diphenhydramine is not readily available, as it is a long-established medication. However, older drugs like diphenhydramine are typically available as generics, indicating that their primary patents have long expired [5]. DrugPatentWatch.com provides information on drug patents and exclusivity periods [5].