• Patients with chronic glaucoma had a carefully scheduled series of intraocular pressure measurements before and after taking acetazolamide for one week at the following dosages: none, 500 mg of sustained-release capsules once a day, 500 mg of capsules twice a day, and 250 mg of tablets four times a day. A capsule taken once a day, which is better tolerated than one taken twice a day by some patients, offers a substantial pressure-lowering effect that lasts at least 23 hours, although the magnitude of the pressure lowering is less than with higher dosages. One capsule twice a day appears to be as effective in the regulation of IOP as one tablet four times a day. The 45% reduction in outflow pressure is achieved with an acetazolamide serum concentration in the range of 15 to 20 μg/mL.
Berson FG, Epstein DL, Grant WM, Hutchinson BT, Dobbs PC. Acetazolamide Dosage Forms in the Treatment of Glaucoma. Arch Ophthalmol. 1980;98(6):1051-1054. doi:10.1001/archopht.1980.01020031041005