Does Kava Cause Excessive Sedation? Understanding the Risks

October 9, 2025 •

4 min read

According to a 2003 study in Molecular Psychiatry, kava extracts caused dose-dependent anxiolytic and sedative effects in animal models, confirming its potential to cause drowsiness and impaired motor function. This raises a critical question for users and clinicians: Does kava cause excessive sedation, and under what circumstances should caution be exercised?

Quick Summary

Kava's sedative effects are dose-dependent and amplified by combining it with other central nervous system depressants. High intake can lead to profound drowsiness, muscle weakness, and poor coordination. Understanding the risks, including dangerous drug interactions, is crucial for safe consumption.

Key Points

Dose-Dependent Sedation: Kava's sedative effects are directly related to the amount consumed; higher intake can lead to excessive drowsiness, muscle weakness, and poor coordination.
Dangerous Drug Interactions: Combining kava with alcohol, benzodiazepines, or other central nervous system depressants is extremely risky and can cause severe, potentially life-threatening sedation.
Unique Mechanism: Kava produces sedation by modulating GABA receptors differently than conventional drugs like benzodiazepines, potentially explaining differences in cognitive side effects and addiction risk.
Surgical Risk: Kava must be discontinued at least two weeks before any surgical procedure to prevent adverse interactions with anesthetics.
Significant Liver Toxicity Risk: A major safety concern with kava is the potential for serious liver damage, which has prompted regulatory warnings and bans in several countries.
Avoid for At-Risk Individuals: Kava should be avoided by individuals with liver disease, Parkinson's disease, or depression, as well as pregnant or breastfeeding women.
Formulation Matters: The potency and risk of sedation can vary widely depending on the kava preparation, with different kavalactone concentrations and delivery methods.

Kava, derived from the roots of the Piper methysticum plant, has a long history of traditional use in Pacific Island cultures for its relaxing and mind-altering properties. In modern contexts, it is often used as a dietary supplement for anxiety and sleep. While its anxiolytic and mild sedative effects are often desired, the risk of excessive sedation is a serious concern, especially with higher intake or certain drug combinations.

The Sedative Mechanism of Kava: How It Works

The sedative and anxiolytic effects of kava are primarily due to a group of compounds called kavalactones. These compounds act on the central nervous system (CNS) through several mechanisms:

GABA-A Receptor Modulation: Kavalactones enhance the activity of GABA receptors, the main inhibitory neurotransmitters in the brain. This increases inhibitory signaling, promoting relaxation and reducing anxiety. Unlike benzodiazepines, kavalactones bind to a different site on the receptor.
Ion Channel Effects: Kava compounds can block voltage-gated sodium and calcium channels, reducing neuronal excitability. This contributes to sedative, muscle relaxant, and local anesthetic properties.
Monoamine Modulation: Kava can affect monoaminergic systems like dopamine and noradrenaline, contributing to its calming effects.

Dose-Dependent Effects: From Relaxation to Excessive Sedation

The level of sedation from kava is directly related to the amount consumed. Small amounts typically provide relaxation and mild sleepiness, along with a common mouth tingling. Larger amounts increase the risk of more pronounced CNS depression, including drowsiness, muscle weakness, reduced coordination (ataxia), and nausea. Extreme intake can lead to severe drowsiness, immobility, disorientation, and slowed breathing. Chronic high consumption is also linked to liver toxicity.

Serious Risks of Combining Kava with Other Depressants

Combining kava with other CNS depressants is dangerous due to synergistic effects that intensify sedation and can have life-threatening consequences. Specific combinations to avoid include:

Alcohol: Greatly increases drowsiness and liver damage risk.
Benzodiazepines: Can cause excessive sedation, dangerous CNS depression, and coma.
Anesthetics: Kava should be stopped two weeks before surgery as it can intensify anesthetic effects.
Opioids and Barbiturates: Intensifies sedative and muscle-relaxant effects.

A Comparison of Sedative Risks: Kava vs. Benzodiazepines


Feature	Kava (Piper methysticum)	Benzodiazepines (e.g., Xanax, Valium)
Mechanism	Enhances GABA-A activity via a distinct binding site, affecting other ion channels and monoamines.	Binds to a specific, classical site on the GABA-A receptor.
Cognitive Effects	May improve cognitive performance at therapeutic intake, with high intake causing impairment.	Can significantly impair cognitive function, reaction times, and memory.
Addiction Potential	Potentially lower risk of addiction due to different receptor binding.	Known to cause dependence and addiction.
Excessive Sedation Risk	High, especially with high intake or when combined with other depressants.	High, particularly with high intake, with overdose potential.
Tolerance	May exhibit "reverse tolerance" initially for some users, but can also lead to standard tolerance with heavy use.	Standard tolerance develops over time, requiring higher intake for the same effect.

Addressing Broader Safety Concerns: Liver Toxicity and Long-Term Use

Beyond sedation, kava use has significant safety concerns, most notably severe liver toxicity. Cases of liver damage, including hepatitis and liver failure, have been linked to kava. While the cause is debated, the risk is real, especially for those with liver conditions or using other hepatotoxic substances. Chronic heavy kava use can also cause kava dermopathy, a reversible skin rash, and other long-term effects like visual disturbances, weight loss, and gastrointestinal issues.

Factors Influencing Kava's Sedative Impact

Several factors affect how kava impacts an individual and the risk of excessive sedation:

Amount and Strength: Higher intake or potent extracts increase risk.
Formulation: Kava comes in various forms (tea, capsules, extracts), with differing kavalactone concentrations and potential for sedation.
Individual Metabolism: Genetic differences in drug metabolism can influence kava's effects and toxicity risk.
Other Substances: Combining kava with other CNS depressants significantly raises the risk of excessive sedation.

Conclusion: The Importance of Caution and Informed Use

Kava can cause excessive sedation, particularly with higher intake or when combined with other CNS depressants. While its relaxing effects are sought, the risks of misuse, drug interactions, and liver toxicity are substantial. Users should understand that "natural" doesn't guarantee safety, and product variability makes effects unpredictable. Caution is strongly advised. Consulting a healthcare provider before using kava is crucial, especially with existing health issues or other medications.

For more on kava's risks and regulatory status, refer to the U.S. Food and Drug Administration (FDA) consumer advisory.

Frequently Asked Questions

Signs of excessive sedation from kava include profound drowsiness, muscle weakness, impaired coordination (ataxia), slurred speech, and dilated pupils. In severe cases, it can cause inability to move and potentially impact breathing.

No, it is not safe. Mixing kava with alcohol can greatly intensify the sedative effects of both substances and significantly increases the risk of liver damage. This combination can lead to dangerous levels of CNS depression.

Kava and benzodiazepines both enhance GABA receptor activity to produce sedation, but they bind to different sites on the receptor complex. Some studies suggest that kava may cause less cognitive impairment at therapeutic intake, but the risk of excessive sedation is still high, particularly when misused.

For some initial users, a phenomenon known as 'reverse tolerance' can occur, where they need less kava over time to achieve the desired effect. However, regular and heavy use can also lead to standard tolerance and dependence.

If you suspect a kava overdose due to severe symptoms like extreme drowsiness, trouble breathing, or loss of consciousness, you should seek immediate medical attention by calling emergency services.

The sedative potential of kava varies depending on the strength of the active kavalactones, which can be influenced by the plant variety, growing conditions, and preparation method. High-potency extracts or supplements carry a greater risk of excessive sedation compared to traditionally prepared tea.

Yes, kava has several other potential side effects. These include serious liver toxicity, a scaly skin rash called kava dermopathy, gastrointestinal upset, visual disturbances, and changes in blood cells, especially with long-term, heavy use.