Kava, derived from the root of the Piper methysticum plant, is a traditional herbal remedy used in the Pacific Islands for centuries for its relaxing, euphoric effects. However, modern usage in the form of dietary supplements has been associated with significant health risks, particularly when combined with certain medications. The active compounds in kava, known as kavalactones, affect the central nervous system (CNS) and liver, creating a high potential for harmful drug interactions. For this reason, many countries have restricted its sale, and health experts strongly advise against its use with a variety of medications.
Kava and Central Nervous System (CNS) Depressants
One of the most critical drug interactions involves CNS depressants, which are substances that slow down brain activity. Since kava itself has sedative properties, combining it with other depressants can lead to an additive or synergistic effect, causing excessive drowsiness, impaired coordination, and slowed breathing.
Alcohol
Consuming alcohol while taking kava is extremely risky. Both substances are CNS depressants and hepatotoxic (toxic to the liver), so combining them significantly elevates the risk of severe liver damage and profound sedation.
Benzodiazepines
This class of anti-anxiety and sleep medications (e.g., Xanax, Valium, Ativan) can cause excessive sedation and grogginess when combined with kava. In a reported case, a patient taking both alprazolam and kava was hospitalized in a lethargic, semicomatose, and disoriented state. The combination can potentiate the effects of benzodiazepines, leading to dangerously high levels of sedation.
Opioids and Muscle Relaxants
Prescription pain relievers (e.g., codeine, hydrocodone) and muscle relaxants (e.g., cyclobenzaprine) also have a sedative effect. Mixing them with kava can result in enhanced drowsiness and impaired motor function, which can be particularly dangerous when driving or operating heavy machinery.
Sleep Medications and Antihistamines
Over-the-counter and prescription sleep aids (e.g., zolpidem) and certain antihistamines that cause drowsiness (e.g., diphenhydramine) are another major concern. The combination with kava can cause an extreme level of sedation that is hazardous to daily activities.
Kava and Liver-Damaging (Hepatotoxic) Drugs
Kava has been implicated in rare but serious cases of liver injury, including liver failure requiring transplantation. Combining it with other medications that are also metabolized by or are toxic to the liver can overwhelm the organ and increase the risk of severe damage.
Some of the specific medications that can harm the liver include:
- Acetaminophen (Tylenol): This common pain reliever, especially in high doses or with chronic use, is hepatotoxic. Taking it with kava significantly elevates the risk of liver damage.
- Statins: Certain cholesterol-lowering drugs, such as atorvastatin and lovastatin, are metabolized by the liver.
- Antibiotics: Medications like isoniazid can be damaging to the liver.
- Other Hepatotoxins: Amiodarone, methotrexate, and methyldopa are also known to be harmful to the liver and should not be mixed with kava.
Kava and Psychiatric Medications
Kava's effects on the brain's neurotransmitter systems mean it can have unpredictable and dangerous interactions with psychiatric medications.
- Antidepressants: Including selective serotonin reuptake inhibitors (SSRIs like Prozac or Zoloft), tricyclics, and monoamine oxidase inhibitors (MAOIs), should not be taken with kava. Combining them can worsen depression or lead to harmful side effects.
- Antipsychotics: Kava affects dopamine and can increase the risk of side effects like involuntary muscle spasms, or dystonic reactions, in individuals taking antipsychotics.
Kava and Medications for Parkinson's Disease
Kava can interfere with the brain's dopamine system. This is particularly dangerous for individuals with Parkinson's disease, as it can counteract the effects of medications designed to increase dopamine levels.
Specifically, kava may reduce the benefit of levodopa and increase dopaminergic toxicity when taken with other Parkinson's medications like ropinirole.
Kava and Other Important Drug Interactions
In addition to the major categories above, other medications and substances should be avoided:
- Blood Thinners (Anticoagulants): Kava may interfere with medications like warfarin, potentially increasing the risk of bleeding.
- General Anesthesia: Kava can intensify the effects of anesthetics and should be discontinued at least two weeks before any scheduled surgery.
- Cytochrome P450 Enzymes: Kava inhibits several cytochrome P450 (CYP) enzymes, including CYP2C19, CYP2C9, and CYP2E1. These enzymes are crucial for metabolizing a wide range of drugs, so kava can alter how quickly the body breaks down many medications, leading to increased drug levels and side effects.
Kava Interaction Comparison Table
| Drug Class | Example Medications | Potential Interaction | Risk/Severity |
|---|---|---|---|
| CNS Depressants | Alcohol, Alprazolam (Xanax), Diazepam (Valium), Opioid painkillers, Muscle relaxants, Sleep aids | Excessive sedation, drowsiness, impaired coordination, breathing problems | High |
| Hepatotoxic Drugs | Acetaminophen, Statins, Isoniazid, Methotrexate | Increased risk of severe liver damage, hepatitis, or liver failure | High |
| Psychiatric Medications | SSRIs (e.g., Zoloft), MAOIs, Antipsychotics | Worsened depression, increased side effects, altered drug metabolism | High |
| Parkinson's Disease Meds | Levodopa, Ropinirole | Reduced medication effectiveness, increased dopaminergic toxicity | High |
| Blood Thinners | Warfarin (Coumadin) | Interference with blood clotting, increased risk of bleeding | Moderate to High |
| Anesthetics | Medications used for surgery | Intensified sedative effects, potential for complications during surgery | High |
Conclusion: The Importance of Professional Guidance
Given the serious nature of its interactions, kava is not a benign herbal supplement. The potential for severe liver injury, excessive sedation, and dangerous interference with a wide array of prescription medications means it should never be taken without consulting a healthcare professional. Individuals taking any medication, especially those with pre-existing liver conditions, should discuss the risks thoroughly with a doctor or pharmacist. Relying on self-medication with kava can lead to life-threatening complications, and safer, more effective treatments exist for anxiety, insomnia, and stress. Always prioritize professional medical advice when considering any supplement, particularly one with such a documented history of dangerous interactions. For more information on kava and drug interactions, consulting resources like the National Center for Complementary and Integrative Health (NCCIH) is highly recommended.(https://www.nccih.nih.gov/health/kava)
