Incidence and clinical relevance of the interactions and side effects of hypericum preparations

Observational studies with preparations of St, John's wort have recorded an incidence of adverse events (AE) among those treated of between 1 and 3%, This is some ten times less than with synthetic antidepressants. The most c ommon adverse events (1 per 300,000 treated cases) among the spontaneous re ports in the official register concern reactions of the skin exposed to lig ht. Investigations in volunteers have shown that the threshold dose for an increased risk of photosensitisation is about 24 g/day of a usual commercia l extract (equivalent to approximately 5-10 mg of the hypericin that causes the phenomenon), In view of the newly observed side effects and interactio ns, the following additional restrictions on use appear justified: as with all preparations in this group of indications, hypericum preparations must not be taken at the same time as other antidepressants, If co-medication wi th coumarin-type anticoagulants is unavoidable, it must only be undertaken provided clotting parameters are closely monitored by the physician, Go-med ication with ciclosporin and indinavir, and for the time being, other prote ase inhibitors used in anti-HIV treatment, is absolutely contraindicated. W ithout exception, all preparations of St. John's wort must only be availabl e through pharmacies.