Significant metabolic acidosis induced by acetazolamide. Not a rare complication.

Blood gas and serum electrolyte levels were measured in 27 elderly patients (mean age +/- SD, 63.3 +/- 13.5 years) who were receiving acetazolamide (250 to 1,000 mg/day) for glaucoma. Eleven glaucomatous patients (mean age, 69.1 +/- 7.4 years) who were not receiving acetazolamide served as a control group. In the acetazolamide-treated group, four patients (14.8%) had mild acidosis (7.29 greater than pH less than or equal to 7.31), ten (37%) had moderate acidosis (7.20 greater than pH less than or equal to 7.29), and one patient (3.7%) had severe acidosis (pH, 7.15). None of the patients in the control group had acidosis. It is concluded that moderate metabolic acidosis of potential clinical significance is common among glaucomatous elderly patients who receive acetazolamide. The exact clinical significance of our observations is yet to be determined.