An adrenergic alpha-agonist is a drug which selectively stimulates alpha adrenergic receptors. The alpha-adrenergic receptor has two subclasses α1 and α2. Although complete selectivity between receptor agonism is rarely achieved, phenylephrine is an α1 agonist, while clonidine and methyldopa are α2 partial agonists .
An example is xylazine.
Alpha-adrenergic agonists are used in the treatment of glaucoma by decreasing the production of aqueous fluid by the ciliary bodies of the eye.
- Pharmacology (3rd Edition) Rang, Dale and Ritter