Kava is a beverage or extract made from the Piper methysticum plant. In the South Pacific, it's a popular drink that is used in ceremonies for relaxation.
The name "kava" comes from the Polynesian word "awa," which means bitter. Kava affects the brain and other parts of the central nervous system. Chemicals called kavalactones that are found in kava are believed to be responsible for its effects.
People commonly use kava for anxiety. It's also used for stress, withdrawal from drugs called benzodiazepines, sleeping problems, and many other purposes, but there is no good scientific evidence to support many of these uses.
Cases of liver damage and even some deaths have been linked to kava use. Because of this, kava was taken off the market in Europe and Canada in the early 2000s. But after reviewing the evidence, most countries have allowed kava to return to the market. Kava was never taken off the market in the US.
Is It Effective?
NatMed Pro rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
- Anxiety. Taking kava by mouth for at least 5 weeks seems to reduce anxiety and might work as well as some prescription anti-anxiety medications.
- A type of persistent anxiety marked by exaggerated worry and tension (generalized anxiety disorder or GAD). Taking kava by mouth doesn't seem to improve symptoms of GAD.
There is interest in using kava for a number of other purposes, but there isn't enough reliable information to say whether it might be helpful.
Is it Safe?
When taken by mouth: Kava is possibly safe when taken for up to 6 months. Using kava can make it difficult to drive or operate machinery safely. Do not take kava before you plan on driving. "Driving-under-the-influence" citations have been issued to people driving erratically after drinking large amounts of kava tea.
People might have heard that using kava can cause liver damage. This seems to be rare and is most often linked to long-term use of very high doses. Most people who have used kava haven't experienced liver toxicity. Also, past cases of liver toxicity might not be due to kava. Other factors may have contributed to these toxic effects.
Special Precautions & Warnings:
Pregnancy and breast-feeding: Kava is possibly unsafe when taken by mouth while pregnant or breast-feeding. It might affect the uterus while pregnant. Also, some of the chemicals in kava can pass into breast milk and might hurt a breast-fed infant. Avoid using it.
Liver disease: People who have liver problems should avoid kava. It might make liver disease worse.
Parkinson disease: People who have Parkinson disease should avoid kava. It might make this condition worse.
Surgery: Kava affects the central nervous system. It might increase the effects of anesthesia and other medications used during and after surgery. Stop using kava at least 2 weeks before a scheduled surgery.
Alcohol (Ethanol)
Interaction Rating=Moderate Be cautious with this combination.
Using kava with alcohol might increase the effects of alcohol on the central nervous system. This might increase the risk for some side effects, such as drowsiness and mood changes. Also, kava might harm the liver. Taking kava along with alcohol might increase the risk of liver damage.
Haloperidol (Haldol)
Interaction Rating=Moderate Be cautious with this combination.
Haloperidol is broken down by the liver. Kava might decrease how quickly the liver breaks down this medication. This might increase the effects and side effects of haloperidol.
Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)
Interaction Rating=Minor Be watchful with this combination.
Some medications are changed and broken down by the liver. Kava might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 2C19 (CYP2C19) substrates)
Interaction Rating=Moderate Be cautious with this combination.
Some medications are changed and broken down by the liver. Kava might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 2C9 (CYP2C9) substrates)
Interaction Rating=Moderate Be cautious with this combination.
Some medications are changed and broken down by the liver. Kava might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 2D6 (CYP2D6) substrates)
Interaction Rating=Minor Be watchful with this combination.
Some medications are changed and broken down by the liver. Kava might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 2E1 (CYP2E1) substrates)
Interaction Rating=Moderate Be cautious with this combination.
Some medications are changed and broken down by the liver. Kava might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications changed by the liver (Cytochrome P450 3A4 (CYP3A4) substrates)
Interaction Rating=Minor Be watchful with this combination.
Some medications are changed and broken down by the liver. Kava might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.
Medications moved by pumps in cells (P-Glycoprotein Substrates)
Interaction Rating=Moderate Be cautious with this combination.
Some medications are moved in and out of cells by pumps. Kava might change how these pumps work and change how much medication stays in the body. In some cases, this might change the effects and side effects of a medication.
Medications that can harm the liver (Hepatotoxic drugs)
Interaction Rating=Moderate Be cautious with this combination.
Kava might harm the liver. Some medications can also harm the liver. Taking kava along with a medication that can harm the liver might increase the risk of liver damage.
Ropinirole (Requip)
Interaction Rating=Moderate Be cautious with this combination.
Ropinirole is broken down by the liver. Kava might decrease how quickly the liver breaks down this medication. This might increase the effects and side effects of ropinirole.
Sedative medications (CNS depressants)
Interaction Rating=Major Do not take this combination.
Kava might cause sleepiness and slowed breathing. Some medications, called sedatives, can also cause sleepiness and slowed breathing. Taking kava with sedative medications might cause breathing problems and/or too much sleepiness.
Herbs and supplements that might harm the liver: Kava might harm the liver. Taking it with other supplements that can also harm the liver might increase the risk of liver damage. Examples of supplements with this effect include garcinia, greater celandine, green tea extract, and kratom.
Herbs and supplements with sedative properties: Kava might cause sleepiness and slowed breathing. Taking it along with other supplements with similar effects might cause too much sleepiness and/or slowed breathing in some people. Examples of supplements with this effect include hops, L-tryptophan, melatonin, and valerian.
There are no known interactions with foods.
Kava is available in many different types of products, including teas and other beverages. Kava extracts have most often been used by adults in doses of 150-400 mg by mouth daily for up to 2 years. Speak with a healthcare provider to find out what type of product and dose might be best for a specific condition.
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