TABLE 2.
Notable pharmacokinetic herb-drug interactions
| Enzyme | Botanical | Dose (day−1), duration | Probe;a effectb |
|---|---|---|---|
| CYP3A4 | Goldenseal | 600 mg, 12 d | CsA; inhibition (133) |
| Echinacea | 1600 mg, 8 d | MDZ; induction of hepatic 3A4, inhibition of intestinal 3A4 (134) | |
| St. John’s Wort | Various | Various; induction (135) | |
| Ginseng | 2000 mg, 28 d | MDZ; induction (136) | |
| Green Tea extract | 800 mg, 4 wk | Buspirone; inhibition (137) | |
| CYP2D6 | Goldenseal | 2700 mg, 28 d | Debrisoquine; inhibition (138) |
| 3210 mg, 14 d | Debrisoquine; inhibition (139) | ||
| CYP1A2 | Echinacea | 1600 mg, 8 d | Caffeine; inhibition (134) |
| 1600 mg, 28 d | Caffeine; inhibition (p = 0.07, not clinically relevant) (140) | ||
| Kava kava | 1000–4000 mg, >6 years (analysis following 30-day cessation) | Caffeine; inhibition (141) | |
| CYP2E1 | Garlic | 1500 g, 28 d | CZX; inhibition (142) |
| Kava kava | 2000 mg, 28 d | CZX; inhibition (138) | |
| CYP2C19 | Ginkgo biloba | 280 mg, 12 d | OPZ; induction (genotype effect) (143) |
| St. John’s Wort | 900 mg, 14 d | S-mephenytoin; induction (genotype effect) (144) | |
| CYP2C9 | Milk thistle | 420 mg, 14 d | Losartan; inhibition (genotype effect) (145) |
| Goldenseal | 900 mg, 14 d | Losartan; inhibition (146) | |
| Echinacea | 1600 mg, 8 d | Tolbutamide; inhibition (134) | |
| OATP1A2 | Green Tea extract | 637 mg, 14 d | Nadolol; inhibition (147) |
| P-glycoprotein | Garlic | 1200 mg, 21 d | Saquinavir; induction (148) |
| Ginkgo biloba | 360 mg, 14 d | Talinolol; inhibition (149) | |
| St. John’s Wort | 2000–4000 mg, 14 d | Digoxin; induction (150) | |
a
MDZ: midazolam; CZX: chlorzoxazone; OPZ: omeprazole; CsA: cyclosporin A.
b
Genotype effect: Effect seen in high-efficiency metabolizers but not in low-efficiency.