Dichlorphenamide is a carbonic anhydrase inhibitor. Carbonic anhydrase is a protein in your body. Dichlorphenamide reduces the activity of this protein. Dichlorphenamide is used to treat glaucoma. By inhibiting the actions of carbonic anhydrase, dichlorphenamide reduces the amount of fluid produced in your eyes and therefore also reduces pressure. Dichlorphenamide may also be used for purposes other than those listed in this medication guide.