kava
n. an extract of the root of Piper methysticum, a shrub indigenous to certain southern Pacific islands, where it is used for ritual, social, and recreational purposes. It is a mild intoxicant, sedative, and analgesic agent. The primary active ingredients of the plant are kavain, dihydrokavain, methysticin, and dihydromethysticin—alkaloids that have anticonvulsant and muscle relaxant properties and also produce sedation without clouding of consciousness. Kava is now widely available in Western countries as an herbal supplement promoted for relaxation (e.g., to relieve stress, anxiety, and tension) and as a remedy for sleeplessness and menopausal symptoms, among other uses. These benefits have largely not been definitively determined, and in fact kava-containing supplements have been shown to be ineffective for treating menopausal symptoms. In 2002, the U.S. Food and Drug Administration issued a consumer advisory warning of the potential risk of rare
but serious reactions—including hepatitis, cirrhosis, and liver failure—associated with use of these supplements. Kava has also been associated with depression of the central nervous system or coma (particularly in combination with prescribed anxiolytics), and other less serious adverse reactions (e.g., skin rash) have been reported as well. There are several known and potential interactions of kava with other agents (see drug interactions), including anticoagulants, monoamine oxidase inhibitors, and drugs metabolized by the cytochrome P450 3A4 enzyme (e.g., clonidine, nefazodone, St. John’s wort). Also called ava; kava kava.