Sparteine oxidation polymorphism in Denmark.

Sparteine oxidation was polymorphic among 301 healthy Danish volunteers. Hence 22 subjects or 7.3% were phenotyped as poor metabolizers (PM) whereas 279 subjects were classified as extensive metabolizers (EM). The metabolic ratio (MR) between sparteine and 2- and 5-dehydrosparteine (% of dose) in 12 hrs urine ranged from 0.11-12.6 in EM and from 30-394 in PM. Urinary excretion of 2- and 5-dehydrosparteine also discriminated between PM and EM. Age, sex, and smoking habits did not influence the MR. This study confirms that sparteine is a useful probe drug in pharmacogenetic investigations.