Supplements have few serious interactions
Almost half of dietary supplements taken by patients at home may have potential interactions with drugs but few are serious, new research indicates.
US pharmacists and doctors surveyed 458 outpatients at two centres. Of
these, 43 per cent were taking at least one dietary supplement with a
prescription medicine. Among these, 45 per cent had a potential for interaction,
although most would not have been serious. However, there was a 6 per
cent incidence of potentially severe interactions. Most of the potential
interactions were with ginseng, garlic, Ginkgo biloba and co-enzyme Q10.
“We encourage all health care providers to question patients about
dietary supplement use, especially because there are increasing reports
of significant
morbidity and mortality, with or without concomitant pharmaceutical use,” they
say.
They add that health care providers should consider potential drug-dietary
supplement interactions regardless of their severity, because even minor
interactions could affect drug therapy and patients’ quality of
life.
However, one author added that the small incidence of serious interactions
was “encouraging news for the millions of patients currently taking
prescription medications along with dietary supplements” (Archives of Internal Medicine 2004;164:630).
Potentially severe interactions
|
Supplement and drug
|
Interaction |
Calcium and fluoroquinolone
|
Decreased absorption
of drug (probable) |
Potassium and angiotensin
converting enzyme inhibitors |
Hyperkalaemia (probable) |
Co-enzyme Q10 and
warfarin |
Decreased international
normalised ratio (INR) (possible) |
Ginkgo biloba and
warfarin |
Increased INR (possible) |
St John’s wort
and serotonin reuptake inhibitors |
Increased serotonin
levels (probable) |
|
|
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