Important herb/drug interactions
WASHINGTON, DC. It is estimated that almost 20 per cent of all
Americans who use pharmaceutical drugs also use medicinal herbs
and high-dose vitamins - and 61.5 per cent of them do not tell
their physicians that they do. This situation could be dangerous
as many drugs and herbs interact with each other. Dr. Adriane
Fugh-Berman MD, a researcher at the George Washington University
School of Medicine and Health, has just released the results of
her investigation into potential herb/drug reactions. Some
highlights of her findings are:
- Chili pepper (Capsicum) may interact with ACE
inhibitors resulting in coughing.
- Danshen (Salvia miltiorrhiza), devil's claw, dong quai,
garlic, Ginkgo biloba, ginseng (Panax spp), and
papaya may interact with warfarin (Coumadin) to increase bleeding
- Siberian ginseng may heighten the effects of digoxin.
- Ginkgo biloba may interact with aspirin and
acetaminophen (Tylenol, Paracetamol) to cause bleeding.
- Licorice (Glycyrrhiza glabra) may interact with
prednisolone, hydrocortisone, and oral contraceptives.
- Psyllium (Plantago ovato) may interact with lithium.
- St. John's wort can cause a mild serotonin syndrome if taken
with serotonin-reuptake inhibitor antidepressants. It can reduce
the effects of digoxin and cyclosporin and can cause bleeding when
taken with combined oral contraceptives.
- Tamarind (Tamarindus indica) can increase the effects
- Yohimbine (Pausinystalla yohimbe) can cause
hypertension if taken with tricyclic antidepressants.
- The laxatives senna (Cassia senna), cascara (Rhamnus
purshiana) and soluble fibers such as guar gum and psyllium
can decrease the absorption of many pharmaceutical drugs.
Dr. Fugh-Berman is particularly concerned that patients with blood
clotting disorders, on anticoagulant therapy, and awaiting surgery
be warned against the concurrent use of ginkgo, danshen, dong
quai, papaya, and garlic.
Fugh-Berman, Adriane. Herb-drug interactions. The Lancet, Vol. 355, January 8, 2000,