Disopyramide decreases the fasting serum glucose level in man

The effect of disopyramide, a class Ia antiarrhythmic drug, on the serum gl ucose level was evaluated in 6 consecutive in-patients. A 19-hour starvatio n test was repeated with oral administration of sustained-release disopyram ide (150 mg) 0 and 12 hours after starting the test. Serum glucose levels d uring 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). T he average reduction of the serum glucose level by disopyramide in each pat ient 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 lev els. 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 d isopyramide 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 se vere hypoglycemia but also the decrease in glucose levels were influenced b y multiple factors including age and body weight.