If you are currently being treated with any of the following medications, you should not use kava without first talking to your healthcare provider:

Anticonvulsants
Kava may exaggerate the effects of medications used to treat seizures.

Central Nervous System (CNS) depressants
Kava may enhance the effects of CNS depressants such as benzodiazepines used for sleep disturbances or anxiety (particularly alprazolam) and barbiturates used for sleep disorders and seizures (such as pentobarbital). In fact, there has been one report of someone going into a coma from the combination of kava and alprazolam.

Antipsychotic medications
Kava may increase the risk of unpleasant side effects associated with phenothiazine medications (often used for the treatment of schizophrenia), such as chlorpromazine and promethazine.

Levodopa
There has been at least one report that kava may reduce the effectiveness of levodopa, a medication used to treat Parkinson's disease. Therefore, you should not take this herb if you are taking any medications containing levodopa.