Pharmacokinetic study of cimetidine in pediatric duodenal ulcer

The subjects were five schoolboys aged 7 to 12 years with endoscopically proved duodenal ulcers. After the oral administration of 10 mg/kg of cimetidine, the mean peak cimetidine level was 2.86 microgram/ml; the time to peak level was 1.3 hours; the area under the concentration-time curve was 9.74 microgram/ml.hr; the elimination half-life was 1.55 hours; and 56% of the drug was excreted unchanged in the urine. The plasma cimetidine level remained above 1.0 microgram/ml for 3.4 hours and above 0.5 microgram/ml for 5.8 hours. Gastric pH was increased to 5 or above for three to six hours. These results are similar to those reported previously in other pediatric patients. After eight weeks of treatment with 20 mg/kg of cimetidine daily, the duodenal ulcers were completely healed in four of five patients studied.