Differential effect of type I and type II diabetes mellitus on serum ampicillin levels

Ampicillin elimination was studied in 10 poorly controlled, 6 well controlled type I and 14 poorly controlled type II diabetic patients. Two groups of age-matched healthy volunteers served as controls. After oral administration of ampicillin (500 mg), the poorly controlled type I diabetics had significantly lower serum concentration of the drug when compared to their corresponding healthy controls. The elimination half-life (t1/2) remained unaltered. Their creatinine clearance rate and urinary excretion of the drug were significantly reduced. There was no difference in these parameters between well controlled diabetics and healthy volunteers. The bioavailability data calculated from the urinary recovery of the drug, after oral and i.v. administration, suggested reduced oral absorption in poorly controlled type I diabetic patients. Ampicillin kinetics data of poorly controlled type II diabetic patients were not significantly different from that of the control group. Serum ampicillin levels and urinary excretion of the drug were similar in these groups. It is concluded that serum ampicillin level may be lower in poorly controlled type I diabetics which may be due to reduced absorption of the orally administered drug.