Metabolic acidosis in patients receiving anticonvulsants

Blood pH, bicarbonate, PCO2, serum calcium, alkaline phosphatase and red cell carbonic anhydrase were measured in 37 selected patients receiving anticonvulsants. Patients with metabolic acidosis showed a high incidence of hypocalcemia with increased alkaline phosphatase and a significant reduction of carbonic anhydrase-B activity. High iPTH levels were found in 13 patients, but this was not correlated with acid-base balance status. Anticonvulsant drugs seemed to inactive carbonic anhydrase-B activity. Metabolic acidosis might be one of the factors causing a disturbance of calcium metabolism in these patients.