Disopyramide Decreases the Fasting Serum Glucose Level in Man

The effect of disopyramide, a class Ia antiarrhythmic drug, on the serum glucose level was evaluated in 6 consecutive in-patients. A 19-hour starvation test was repeated with oral administration of sustained-release disopyramide (150 mg) 0 and 12 hours after starting the test. Serum glucose levels during the starvation test decreased with disopyramide administration from a mean value of 96.5 ± 1.8 to 85.9 ± 1.4 mg/dl (24 samples, p < 0.05). The average reduction of the serum glucose level by disopyramide in each patient was 9.7 ± 2.2 mg/dl. The decrease in the serum glucose level was not related to the serum concentration of disopyramide or serum creatinine levels. The decrease in the serum glucose level was larger in older patients (r = 0.75) and in light patients under 45 kg. These results suggested that disopyramide reduced the fasting serum glucose levels even in normal ranges as a common side effect of the drug, and that not only the occurrence of severe hypoglycemia but also the decrease in glucose levels were influenced by multiple factors including age and body weight.