The short answer
Kava has its own liver-safety concerns and needs review during isoniazid treatment. No direct study established that this exact combination increases liver injury, but adding a potentially hepatotoxic product is a meaningful precaution.
What this answer covers
Piper methysticum aqueous extracts and other oral kava preparations; not a uniform all-product exposure.
- Supplement or preparation
- Piper methysticum
- Medication ingredient
- isoniazid
The medication already requires liver vigilance
Isoniazid can cause serious hepatitis, and its label calls for attention to symptoms and individual risk factors. This medicine warning does not supply an injury rate for the supplement combination.
What the original supplement evidence shows
Original reports describe hepatitis after traditional aqueous kava. A small short trial of another aqueous preparation reported no clinical hepatotoxicity. The null trial does not exclude a rare event or establish co-use safety.
Separate intrinsic harm from a proven interaction
The sources support concern about the specified supplement exposure itself. They do not demonstrate synergistic injury, a safe combined dose or the same effect for every preparation. A biochemical change is not automatically liver failure.
Discuss the product before adding it
Show the TB clinician the exact product and dose. Do not add an oral product with liver-injury concerns without clinical review. Seek prompt medical advice for jaundice, dark urine, persistent nausea or unusual fatigue rather than trying a spacing interval.
Evidence and practical considerations
Side effects & toxicity
Conditional hepatic co-use precaution from exact medication warning and original preparation-specific supplement liver evidence. No exact-pair increased incidence or synergistic causality established; route/preparation limits and contrary findings retained.
- Exact scope
- Piper methysticum aqueous extracts and other oral kava preparations; not a uniform all-product exposure. with Isoniazid oral tablets.
- Medication form and route
- oral medication; oral supplement
What remains uncertain
- No unmeasured pair incidence, blanket class transfer or arbitrary spacing interval.
Factors that may matter: Preparation; Dose; Other medicines; Organ function.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 11, 2026
Population: People prescribed isoniazid
Hepatitis and peripheral-neuropathy warnings; pyridoxine recommended in predisposed patients; tyramine/histamine food precautions.
How this applies: Exact isoniazid RxCUI 6038 IN, with stated salt/formulation/route bridge.
Exact route and formulation apply. Label precautions do not quantify untested botanical pairs or support arbitrary supplement doses.
Source 2: Original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 11, 2026
Population: Two cases and27 heavy kava consumers.
Hepatitis cases considered probably related; isolated GGT elevations in many heavy users were not interpreted as proof of liver injury.
How this applies: No isoniazid co-use; case attribution and small survey, preparation-specific.
No isoniazid co-use; case attribution and small survey, preparation-specific.
Source 3: Original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 11, 2026
Population: 60 adult participants recruited in placebo-controlled crossover.
No clinical hepatotoxicity or serious adverse effects reported.
How this applies: Short small trial cannot exclude rare liver injury or establish isoniazid combination safety.
Short small trial cannot exclude rare liver injury or establish isoniazid combination safety.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Research summary published | |
| Editorial update | |
| Corrected missing spaces between numbers and units or words in the copy before registration; evidence and conclusions unchanged. | |
| Article prepared | |
| Prepared exact isoniazid article with formulation-specific evidence and uncertainty. |
Article revision: c959a4c5204591a6
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.