Table 1.
Dextromethorphan/dextrorphan and mephenytoin S/R metabolic ratios in CYP2D6 and CYP2C19 extensive metabolisers, respectively, and demographic data divided according to gender and use of oral contraceptives (OCs).
| Dextromethorphan/dextrorphan (CYP2D6) | Mephenytoin S/R (CYP2C19) | |||||
|---|---|---|---|---|---|---|
| Men (n = 285) | Women not using OCs (n = 176) | Women using OCs (n = 82) | Men (n = 316) | Women not using OCs (n = 190) | Women using OCs (n = 82) | |
| Metabolic ratio | 0.080 | 0.067 | 0.062 | 0.089 | 0.090 | 0.230 |
| median (range) | 0.002–0.0857 | 0.00–0.079 | 0.01–0.083 | 0.006–0.530 | 0.006–0.650 | 0.010–0.659 |
| Ln metabolic ratio mean (s.d.) | −2.49 (1.04) | −2.72 (1.15)* | −2.78 (1.11) | −2.45 (0.86) | −2.49 (0.83) | −1.67 (0.84)** |
| Age (years) mean (s.d.) | 26.2 (6.5) | 27.6 (8.0) | 23.8 (4.4) | 26.2 (6.3) | 27.9 (8.2) | 24.0 (5.0) |
| Body weight mean (s.d.) | 76.5 (10.5) | 62.3 (9.3) | 61.8 (8.4) | 76.4 (10.5) | 62.2 (9.1) | 61.9 (8.7) |
| Caffeine intake mean (s.d.)(mg day−1) | 250 (190) | 280 (220) | 190 (170) | 240 (190) | 290 (220) | 190 (170) |
| Current smokers number (%) | 37 (13) | 14 (8) | 11 (14) | 38 (12) | 16 (8) | 9 (11) |
*
Men vs women not using OCs P = 0.033 (mean difference 0.23, 95% confidence interval 0.03–0.43).
**
Women using OCs vs women not using OCs P < 0.001 (mean difference 0.82, 95% confidence interval 0.60–1.04).