DEXTROMETHORPHAN O-DEMETHYLATION POLYMORPHISM IN JORDANIANS

The O-demethylation of dextromethorphan (DMT) to dextrorphan (DRP) was studied in 241 unrelated, healthy Jordanian volunteers (171 males, 70 females). Urine was collected for 8 h following a single oral dose of DMT bromhydrate 30 mg. A thin-layer chromatographic (TLC) technique w as used to identify the metaboliser phenotype. The frequency of the po or metaboliser phenotype was found to be 2.9% (approximate 95% confide nce interval 0.8-5.0%). Applying the Hardy-Weinberg Law, the frequency of the recessive autosomal gene controlling poor metabolism was 0.17 (95 % confidence interval 0.108-0.232).