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scaly, yellowed skin, blood abnormalities, apathy, kidney damage, seizures, psychotic
syndromes, and increased blood pressure in the lungs (pulmonary hypertension). Blood
in the urine has also been reported. Less common side effects include restlessness,
drowsiness, lack of energy, and tremor. In four cases, kava was associated with
dyskinesias or worsening Parkinsonian symptoms.
Feelings of sedation (drowsiness) are inherent in the use of kava. The Natural Standard
adds: eye irritation, ECG abnormalities, shortness of breath, bleeding, irritation in the
layers around the brain and spinal cord, urinary retention, skin lesions, enhanced or
decreased cognitive performance, anorexia, sleeplessness, abnormal sensations called
paresthesias, vomiting, and dangerously high blood pressure.
People should use great care in operating heavy machinery while taking kava because
the herb has been reported to cause drowsiness.
- DOSAGE: A dose-finding study using 150 to 300 mg. per day found that improvement was
more “robust” with higher doses. Mischoulon and Rosenbaum report that there is no
consensus on the optimal daily dose, and lack of a standardized extract makes comparison
impossible. But Mischoulon and Rosenbaum cite dosages of 150 to 300 or 400 mg. per day.
Weil recommends 100 to 200 mg two or three times a day, as needed ( 300 - 600 mg per
day). Lake and Spiegel agree on three doses of 100 mg per day. The more serious toxic
reactions have been associated with high doses or prolonged use of kava, and use of kava
without physician supervision.
- CAUTION: Duration of use of kava is not recommended to exceed three months.
Mischoulon and Rosenbaum conclude that: “Kava should be prescribed and used with
great caution.”^7
- RESEARCH: More research pinpointing risk factors could modify these recommendations,
since liver toxicity appears to be extremely rare, and bad experience with other anxiolytics
