The risks of combining medicine and herbal remedies

The risks of using herbal remedies, considered 'natural', should not be disregarded, as some have serious side effects and some interact with and influence conventional medical therapeutics. The effect may be pharmacokinetic by altering absorption or metabolism, and may be pharmacodynamic, by changing the final effect of the drug. St John's wort, for example, an antidepressant herbal remedy, may pharmacodynamically interact with specific serotonin reuptake inhibitors (SSRI's), causing a serotonin syndrome. St Johns wort also causes serious pharmacokinetic interactions by activating the cytochrome CYP3A4, dangerously decreasing blood levels of cyclosporin, warfarin, and theophylline, and reducing the efficacy of contraceptive pills and AIDS therapy. The article presents a review of a number of herbal remedies, commonly used in Israel, that have documented drug interactions, providing details of common indications, adverse reactions and drug interactions of each herbal remedy. Physicians should recognize the fact that patients use herbal remedies, purchased directly at pharmacies or health stores, and be aware of the potential interactions of these remedies with conventional drugs.