Risk and safety in practice

A very recent Canadian paper by Shelagh McRae presents the story of a heart patient of 74 who had been stabilized on the same dose of digoxin for many years; then on a routine control visit he was suddenly found to have a raised serum digoxin level. The most likely causes of such a problem such as overdosage or renal failure were ruled out, and the matter remained a mystery until the patient informed the doctor that he had been taking Siberian ginseng. Once he abandoned the ginseng, his serum digoxin returned to normal. A few months later, when he took ginseng again, the problem recurred. The author speculates that some component of the ginseng may have been converted to digoxin in vitro, interfered with digoxin excretion or caused a false serum assay result. Rightly, she warned physicians to be alert to the possibility that a patient's self-medication with 'alternative' remedies can lead to troublesome interactions. Ginseng is a familiar problem in this respect. Cardiovascular and oestrogen-like effects have been attributed to it, and it has on more than one occasion deranged prescribed drug therapy in one way or another. The basic problem is undoubtedly that ginseng preparations usually fall outside the scope of drug control and there is as a result no certainty as to their composition. As that grand expert in the problems of complementary therapies, Prof. E. Ernst has pointed out, the term 'ginseng' can refer to any of several Panax species, as well as to so-called ginseng species from Siberia, Romania or Brazil which are in fact rather different plants. No-one knows what a given 'ginseng' preparation contains; one investigator known to this Journal found a so-called ginseng tonic to consist of turnips floating in cheap wine. Anyone who is rash enough to take ginseng, especially alongside prescribed medication, needs to be warned that he is taking quite a step into the unknown.