Voluntary suspension of Kava-kava sales following safety concerns

The Medicines Control Agency (MCA) and Committee on Safety of Medicines (CSM) have welcomed as responsible the decision by a number of organisations representing manufacturers, retailers and herbal practitioners to ask their members to withdraw from sale temporarily any remedies containing the herbal ingredient Kava-kava.

This voluntary move is a precautionary measure in the light of serious liver side effects reported in Germany and Switzerland. No such adverse effects have been seen in the UK.

Kava-kava (Piper methysticum) is used extensively in Europe as a traditional herbal remedy for the treatment of anxiety and in the UK also for ailments affecting the bladder and digestive tracts. In the UK Kava-kava is widely available over the counter. Although three products are licensed, the majority of Kava-kava containing products are unlicensed and available over the counter under the section 12 exemption of the 1968 Medicines Act. Some products are also sold as food.

The 30 cases of hepatotoxicity reported from Germany and Switzerland varied in severity from abnormal liver function to liver failure. There were six cases of liver failure, one of which was fatal and four required liver transplants; the sixth case was being evaluated for a transplant at the time of reporting. Onset of the reactions varied from two weeks to two years. In a number of these cases, however, the evidence was complicated by other factors such as concomitant drugs which themselves have previously been linked with liver problems.

The MCA is currently assessing the emerging evidence on Kava-kava and its effects on the liver. In the meantime, in view of potential concerns over safety it would be prudent for the public to stop taking any product or remedy containing Kava-kava. There should not be any adverse effects from stopping the medication abruptly. Anyone concerned about their health should talk to their doctor or pharmacist.

Kava-kava may also be used as an ingredient in certain food products. In the light of these reports the Food Standards Agency (FSA) is advising consumers to avoid these products as a precautionary measure, until further information on safety is available. The FSA has said that it too would support similar voluntary action by industry on products containing Kava-kava that are sold under food law.