Topical Carbonic Anhydrase Inhibitors

Carbonic anhydrase inhibitors (CAIs) have been used for glaucoma therapy since 1954, following the description of their efficacy by Becker ¹ and Grant et al. ² Despite the fact that these agents reduce intraocular pressure (IOP), their systemic use has been limited by side effects ³ such as malaise, fatigue, weight loss, depression, anorexia, paresthesias, loss of libido, abdominal cramping, gastric burning and irritation, nausea, diarrhea, kidney stones, bone marrow depression, and even potentially fatal side effects such as aplastic anemia. To reduce the adverse effects associated with these agents, creative use has been made of alkalinizing agents, such as bicarbonate or sodium acetate, to decrease the symptom complex related to the metabolic acidosis induced by CAIs. ^3-5 Even with this adjunctive therapy, however, oral CAIs have found limited use in the chronic treatment of glaucoma, primarily because they are poorly tolerated by a significant proportion of patients.