Comparatively few drugs are used in the treatment of glaucoma. Epinephrine, phenylephrine, or hydroxy-amphetamine which usually do not increase intraocular pressure are used in open angle glaucoma to reduce pressure by vasoconstrictive action. Pilocarpine acts directly upon the cholinergic receptor sites to mimic acetylcholine. Neostigmimine, methacholine, and bethanechol are usually contraindicated in narrow angle glaucoma. Acetazolamide is a carbonic anhydrase inhibitor and reduces the rate of secretion of aqueous humor.
However, many drugs used systemically or in the eye for purposes other than glaucoma do raise intraocular pressure and may precipitate acute glaucoma. Those, such as belladonna alkaloids are well known. Others, such as corticosteroids are prescribed for ophthalmic use or systemically, and their intraocular pressure-heightening effect is often overlooked. Often the problem is exacerbated in older people since many take belladonna or other anticholinergic agents, and they are particularly prone to experiencing a rise in intraocular pressure. These are