You’ve probably heard that kava shouldn’t be taken in combination with prescription tranquilizers like Valium, anti-psychotics, or depressants like alcohol. However, that still leaves the question, where does the medical evidence stand when it comes to combining kava and Prozac or other anti-depressants? As many as 30 million Americans have faced depression or anxiety at some point in their lives, and many have taken prescription anti-depressants or anti-anxiety medications to treat these conditions. Prozac is probably the most well known brand of a class of anti-depressants called SSRIs, or selective serotonin reuptake inhibitors, which act to relieve depression by increasing the brain’s amount of the neurotransmitter serotonin.
In our increasingly medicated society, many people are becoming interested in natural ways to relieve anxiety and depression that don’t involve prescription drugs. For many, kava is becoming the herb of choice for its clinically verified anxiolytic and tranquilizing properties, which have been proven to be as effective as certain classes of prescription tranquilizers but without the raft of side effects. However, many kava products also come with warnings not to consume them if you are taking prescription tranquilizers or anti-depressants such as Prozac. There are two reasons why this precaution has been put in place: the first is that, like any psychoactive oral herb, kava must be metabolized by the liver, so taking it in combination with certain drugs can put an undue load on the liver. The second reason is that kava activates pathways in the brain to produce its relaxing and anxiolytic effects, and there is a chance it could interact harmfully with other drugs that affect the central nervous system. We’ll examine both of these areas of concern in more detail below.
You may have heard scary things about kava’s effect on the liver in connection with a 2001 Swiss-German study that linked use of European kava supplements to liver damage in some 30 cases examined in Switzerland. Subsequent research discovered that many of the subjects in the study were taking kava supplements in combination with prescription tranquilizers such as Valium and other benzodiazepines, and/or heavy alcohol consumption. We know now that kava should not be taken in combination with a drug that already puts a metabolic load on the liver, such as alcohol or benzodiazepines, because it can cause harm to the liver. By the same token, the liver must also process anti-depressant SSRIs like Prozac, as well as an older class of anti-depressants called tricyclics. It is possible that taking kava and Prozac could produce a heavy metabolic demand on the liver, so we recommend you consult a doctor before using kava if you already take Prozac or a related anti-depressant.
Furthermore, kava kava is a psychoactive herb, which means it affects chemical pathways in the brain to generate its calming effects. Studies have shown that kava can amplify the effects of central nervous system depressants like alcohol, which contributes to a reduction in anxiety but also slows breathing and heart rate. Doctors already advise against combining kava with CNS depressants, but it’s less clear if kava interacts with SSRI anti-depressants in a significant way. Prozac and other SSRIs work to elevate mood by increasing the brain’s levels of the neurotransmitter serotonin. Kava studies suggest that kavalactones do not interact with the brain’s serotonin pathways; in fact, kavain, a common kavalactone, actually seems to slightly decrease the brain’s amount of serotonin in high amounts. Instead, researchers have suggested that kavalactones reduce anxiety by increasing the brain’s levels of dopamine and norepinephrine. However, the older class of tricyclic anti-depressants can act as monoamine oxidase inhibitors (MAOIs) and have the potential to amplify kava kava’s effects by allowing a greater concentration of kavalactones to pass through the digestive system into the bloodstream.
Kava is not so much an anti-depressant herb (such as St. John’s Wort or kanna) as it is an anxiolytic and tranquilizing herb: kavalactones have been shown to work along the same brain pathway as tranquilizers such as Valium, but without the attendant mental dulling, drowsiness, or potential for habituation. Like synthetic tranquilizers, kava seems to target the amygdala: the region of the brain responsible for regulating fear and anxiety responses, as well as memories with emotional content. While Valium increases the brain’s levels of gamma aminobutyric acid (GABA), a neurotransmitter with anxiolytic properties, kava seems to work by a different pathway. It’s possible that it may interact directly with the voltage-gated ion channels of nerve cells that regulate nerve impulses in order to deliver its anti-convulsant, analgesic, anxiolytic, and muscle relaxant effects.
So far, no one in the medical community is sure what the effects of using kava and Prozac in combination might be. The bottom line is that any herb or medicine that affects your brain will interact with other CNS drugs to some degree. There are already precautions against using kava in combination with CNS depressants or tranquilizers, anti-psychotic medications, and drugs to treat Parkinson’s such as levodopa, but as yet there is very little literature regarding any harmful interactions between kava and Prozac or another SSRI. However, as with any potential drug-herbal combination, we recommend that you refer to a physician for the last word on whether to try kava if you currently use an anti-depressant such as Prozac.