The Primary Warning: Liver Toxicity
Perhaps the most significant and well-documented risk associated with kava use is hepatotoxicity, or liver damage. The FDA issued a consumer advisory in 2002 cautioning consumers about the potential for severe liver injury related to kava-containing products, citing reports of hepatitis, cirrhosis, and liver failure. While some debate exists on the precise cause, factors such as high doses, pre-existing liver disease, alcohol intake, and using non-root plant parts have been implicated. Regardless of the exact mechanism, the risk is substantial enough to warrant a strong warning for certain populations.
For individuals with any form of pre-existing liver or kidney disease, kava is strictly contraindicated. Conditions like hepatitis, non-alcoholic fatty liver disease, or cirrhosis make the liver especially vulnerable to damage from substances, and kava can exacerbate these conditions. The risk is not dose-dependent in these cases, meaning even small amounts could trigger a severe reaction. Regular kava users are advised to get routine liver function tests to monitor for any signs of toxicity.
Potential Mechanisms of Hepatotoxicity
Research into kava's liver toxicity mechanisms suggests several possible pathways. Some theories include the modification of cytochrome P450 (CYP450) enzymes, which are responsible for metabolizing many drugs and other compounds in the body. Another mechanism involves the formation of active metabolites that can be toxic to liver cells. Using inappropriate parts of the plant, such as the stems and leaves instead of just the root, may also introduce more toxic compounds.
Serious Concerns for Specific Health Conditions
Beyond general liver concerns, kava can negatively impact individuals with specific medical conditions due to its pharmacological effects on the central nervous system.
Mental Health Disorders
Patients with certain mental health conditions should be extremely cautious or avoid kava entirely.
- Depression and Bipolar Disorder: Kava may worsen symptoms of depression and is generally not recommended for those with bipolar disorder. Those on antidepressants should also avoid kava, as interactions can occur.
- Psychotic Anxiety and Schizophrenia: Ingestion should be avoided by individuals with serious or psychotic anxiety, as it could worsen symptoms. Similarly, kava is not recommended for those with schizophrenia.
Neurological Conditions
Kava can interfere with neurological function and should be avoided by those with certain disorders.
- Parkinson's Disease: Kava inhibits dopamine reuptake, which can interfere with medications used to treat Parkinson's disease and may worsen symptoms like tremors.
- Epilepsy: Due to its effects on the central nervous system, kava should be avoided by individuals with epilepsy.
Kava and Hazardous Drug Interactions
Combining kava with other substances or medications can lead to dangerous and unpredictable effects. The following list highlights significant interactions:
- Alcohol: The combination of kava and alcohol is especially dangerous, as both are central nervous system depressants. Taking them together increases the risk of sedation, cognitive impairment, and severe liver damage.
- Benzodiazepines (e.g., Xanax, Ativan): Kava and benzodiazepines are both depressants. Concurrent use can lead to higher sedation, grogginess, loss of coordination, and has reportedly caused semicomatose states.
- Antidepressants (SSRIs, MAOIs): Kava can interact with antidepressants, potentially causing excessive drowsiness or other adverse effects. It should not be combined with MAOIs.
- Hepatotoxic Medications (e.g., Acetaminophen): Kava can increase the liver toxicity caused by other medications that are hard on the liver. Combining kava with acetaminophen is particularly risky.
Who Should Avoid Kava: A Comparison Table
| Condition/Status | Reason to Avoid Kava | Risk Level |
|---|---|---|
| Liver Disease | High risk of hepatotoxicity, including liver failure | High |
| Kidney Disease | May worsen existing kidney problems | High |
| Pregnancy/Breastfeeding | Unsafe for fetus and infant; potential for uterus effects | High |
| Mental Health Disorders | May worsen depression, anxiety, and psychotic symptoms | High |
| Parkinson's Disease | May interfere with medication and worsen tremors | High |
| Driving/Operating Machinery | Causes drowsiness and impaired motor skills | High (Situational) |
| Consumption with Alcohol | Increases sedation and risk of liver damage | High (Situational) |
| Using CNS Depressants | Additive sedative effects leading to over-sedation | High |
| Scheduled Surgery | Affects nervous system and interacts with anesthesia | High (Temporary) |
Kava During Pregnancy, Breastfeeding, and Childhood
Kava is considered possibly unsafe for women who are pregnant or breastfeeding and should be avoided in all circumstances. For pregnant women, there is concern that kava may affect the uterus. In one case report, a maternal kava user gave birth to an infant with a dermopathy, which is a skin condition. Furthermore, some of the chemicals can pass into breast milk and potentially harm a breast-fed infant. The lack of safety data and potential risks make it a poor choice for expectant or nursing mothers.
Due to the lack of safety research and the potential for adverse effects on the developing body, kava should not be given to children. There are far safer alternatives available for managing childhood anxiety or sleep issues.
Considerations Before Surgery
If you have surgery scheduled, it is crucial to stop using kava at least two weeks beforehand. Kava affects the central nervous system and can increase the sedative effects of anesthesia and other medications used during and after the procedure. Failing to do so could lead to complications and excessive sedation.
Conclusion: Prioritizing Safety with Kava
While kava is used by some for its calming effects, it is not a harmless herb. The most serious risk is liver toxicity, which can be unpredictable and has been linked to severe injury and even liver failure. For this reason, individuals with pre-existing liver or kidney conditions, those with specific neurological or mental health disorders, and pregnant or breastfeeding women must avoid kava completely. Additionally, combining kava with alcohol or other central nervous system depressants, as well as certain prescription medications, can lead to dangerous and potentially life-threatening interactions.
Anyone considering kava use must first consult with a healthcare professional to discuss potential risks, interactions, and whether it is an appropriate and safe option for their health status. For many people, safer and better-studied alternatives exist for managing anxiety and promoting relaxation. The FDA's ongoing warnings serve as a powerful reminder that "natural" does not always mean safe, and vigilance is necessary with unregulated dietary supplements.
For more information on kava and other supplements, consult reliable medical resources such as the National Center for Complementary and Integrative Health (NCCIH).
