Herbal remedies linked to drug side effects

Interactions between prescription drugs and herbal or dietary supplements can cause complications including heart problems, chest and abdominal pain and headache, according to a review of existing evidence.

Remedies and supplements including ingredients like St John's wort, magnesium, calcium, iron and ginkgo caused the greatest issues, researchers reported in the International Journal of Clinical Practice.

Experts from the China Medical School in Taiwan studied data from 54 review articles and 31 independent studies involving 213 herbal and dietary supplements and 509 prescribed drugs.

A total of 882 linked effects were observed, with warfarin, insulin, aspirin digoxin and ticlopidine among the drugs which were most affected.

Flaxseed, echinacea and yohimbe, a stimulant and aphrodisiac found in Africa, were the herbal ingredients which were found to cause the greatest number of drug interactions.

In almost half of all cases, the drug interactions happened when ingredients in the supplements altered the way in which the prescribed drugs were absorbed and spread around the body, metabolised, and later removed from the system.

A quarter of all the trends noticed were described as "major interactions", with the digestive and nervous systems most commonly affected.

Dr Hsiang-Wen Lin, who led the study, said: "Consumer use of HDS has risen dramatically over the past two decades

"Despite their widespread use, the potential risks associated with combining herbal and dietary supplements with other medications, which include mild-to-severe heart problems, chest pain, abdominal pain and headache, are poorly understood."

In a linked editorial article Prof Edzard Ernst of the University of Exeter said: "Survey after survey shows that large proportions of the population are trying 'natural' remedies for illness-prevention, all sorts of ailments, diseases or for states of reduced well-being.

"Most experts therefore agree that the potential for such interactions is substantial.

"Despite this consensus and despite the considerable amount of documented harm generated by such interactions, our current knowledge is still woefully incomplete." /Telegraph