Kava: Calming but potentially toxic

What is kava?

Kava is an extract from the plant Piper methysticum that grows in the South Pacific island. It is related to black pepper and known as: kava kava, kava pepper, kava root, kawa kawa, intoxicating pepper, ava pepper, and tonga. The active components, kavalactones, are found mostly in the root and rhizome (underground horizontal stem).

To make the traditional kava drink, the roots and rhizomes are ground with water into a paste, filtered, and drunk cold. up. Companies may use chemicals like acetone or ethanol  to extract more kavalactones than water can. These chemicals are not thought to affect efficacy or toxicity. The forms old in the US are solid dosage forms made from powdered kava or liquid solutions.

What is kava used for?

Kava has been used for more than 2000 years by Pacific cultures for its calming effects during rituals and social gatherings. Its use has spread globally, even leading to kava bars in Europe. Kava is believed to promote relaxation, improve mood, and reduce stress and anxiety. There is evidence to support these claims. Kava has not been shown to be effective for generalized anxiety disorder.

Can kava cause liver damage?

Use of commercial preparations of kava have been associated with liver injury, including damage severe enough to result in liver transplantation or death. Because of this, the sale of kava was restricted or banned periodically in several nations, including Germany, France, Switzerland, and Canada. In 2002, the US Food and Drug Administration released an advisory notifying consumers about kava’s potential to cause liver injury.

How kava causes liver damage is not well-understood.  The liver might metabolize kava into substances that directly cause damage to the liver cells.  It is also possible that while metabolizing kava the liver has reduced capacity for metabolizing other drugs, allowing them to accumulate in toxic amounts .

Reports of liver injury are overwhelmingly from commercial preparations. Pacific islanders do not have a higher occurrence of liver injuries attributable to kava. The commercial preparation might include the hepatotoxic leaves, which are not traditionally used, or contaminants from industrial-scale methods of harvesting.

Is kava safe?

For people without liver impairment or not taking any medications that affect the liver, short-term use of kava appears to be safe. A one-time accidental exposure is usually safe.

Side effects of kava

Liver damage is the most concerning risk of long-term kava use. Fatigue, dizziness, and nausea are the most reported adverse events after use of kava. Some who misuse kava develop scaly, cracked skin, which appears to be reversible if kava is discontinued.

What are the symptoms of a kava overdose?

A one-time unintentional dose of kava is usually safe. Large amounts may cause weakness, unsteady gait, and slurred speech, similar to alcohol intoxication.