From the Guidelines
Kava is a plant that has been found to be ineffective for treating chronic insomnia disorder and carries a known risk for acute fatal liver toxicity, leading to a "strong against" recommendation for its use 1.
Key Points
- Kava, scientifically known as Piper methysticum, is a plant native to the South Pacific islands.
- It has been used for centuries as a ceremonial and social drink, and its roots contain compounds called kavalactones that produce mild sedative, anxiolytic, and euphoric effects.
- Recent studies have shown that kava is ineffective for treating chronic insomnia disorder compared to placebo, and it poses a risk for acute fatal liver toxicity 1.
- The U.S. Food and Drug Administration has warned health care providers and the public about the risk for acute liver damage and death associated with kava 1.
- Given these serious potential harms, the work group decided on a “strong against” recommendation for kava.
- Those with liver problems, pregnant women, and people taking certain medications should avoid kava due to potential interactions and health concerns.
- The typical serving at kava bars is about 2-4 ounces of prepared kava, containing approximately 70-250 mg of kavalactones.
From the Research
What is Kava
- Kava, also known as Piper methysticum, is a plant native to the Pacific Island region, and has been used ceremonially for thousands of years 2.
- It is available in the west as an over-the-counter preparation, and its biological effects are reported to include sedative, anxiolytic, antistress, analgesic, local anaesthetic, anticonvulsant, and neuroprotective properties 3.
- The active ingredients of kava are a group of substances known as kavalactones, which have been found to have significant analgesic and anesthetic effects via non-opiate pathways 2.
Uses and Effects of Kava
- Kava's most popular application is as a natural anxiolytic, comparing favorably in several studies to a number of prescription medications, including benzodiazepines 2.
- The pharmacological properties of kava are postulated to include blockade of voltage-gated sodium ion channels, enhanced ligand binding to gamma-aminobutyric acid (GABA) type A receptors, and diminished excitatory neurotransmitter release due to calcium ion channel blockade 3.
- Clinical studies have shown that kava and kavalactones are effective in the treatment of anxiety at subclinical and clinical levels, anxiety associated with menopause, and anxiety due to various medical conditions 3.
Safety and Interactions
- The adverse effects attributed to kava use were considered mild or negligible, except for the occurrence of a skin lesion called kava dermopathy, which occurs only with prolonged use of large amounts of kava and is reversible on reduced intake or cessation 3.
- Rare cases of interactions have occurred with pharmaceutical drugs that share one or more mechanisms of action with the kavalactones, and kava has been implicated in several liver failure cases, leading to its ban in many countries 3, 4.
- However, a direct causal relationship with kava use has been difficult to establish in the majority of the cases, and there is insufficient evidence to implicate kava as the responsible agent 3.