An extensive metabolizer with recurrent ulcer responding to high dose of lansoprazole.

A 51-year-old man underwent surgery for duodenal ulcer in 1983. Ulcer recurred several times. Recently, the patient was receiving 30 mg/day of lansoprazole. On June 15, 2001 hemorrhagic recurrent ulcer was diagnosed. Analysis of CYP2C19 enzyme genotype indicated that the patient was a heterozygous extensive metabolizer, suggesting that 30 mg/day of lansoprazole did not produce effective concentrations of drug in the serum. The dose of lansoprazole was increased to 60 mg/day, and intragastric pH monitoring revealed that a pH > or = 3 was maintained for 99.8% of a 24-hour period, as compared with a previous value of 88.3%. After 3 weeks of treatment, endoscopic examination showed that a red scar had formed at the ulcer site.