ISSN:
1432-1041
Keywords:
Codeine
;
Quinidine
;
CYP2D6
;
hypolagesia
;
drug interaction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Medicine
Notes:
Summary We have studied the hypoalgesic effect of codeine (100 mg) after blocking the hepatic O-demethylation of codeine to morphine via the sparteine oxygenase (CYP2D6) by quinidine (200 mg). The study was performed in 16 extensive metabolizers of sparteine, using a double-blind, randomized, four-way, cross-over design. The treatments given at 3 h intervals during the four sessions were placebo/placebo, quinidine/placebo, placebo/codeine, and quinidine/codeine. We measured pin-prick pain and pain tolerance thresholds to high energy argon laser stimuli before and 1, 2, and 3 h after codeine or placebo. After codeine and placebo, the peak plasma concentration of morphine was 6–62 (median 18) nmol·.l−1. When quinidine pre-treatment was given, no morphine could be detected (〈4 nmol·l−1) after codeine. The pin-prick pain thresholds were significantly increased after placebo/codeine, but not after quinidine/codeine compared with placebo/placebo. Both placebo/codeine and quinidine/codeine increased pain tolerance thresholds significantly. Quinidine/codeine and quinidine/placebo did not differ significantly for either pin-prick or tolerance pain thresholds. These results are compatible with local CYP2D6 mediated formation of morphine in the brain, not being blocked by quinidine. Alternatively, a hypoalgesic effect of quinidine might have confounded the results.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00265920
