The short answer
Avoid adding kava to lorazepam without prescriber review. Official kava guidance advises against combining it with sedating substances.
What this answer covers
Oral Piper methysticum; extract, dose and other sedatives must be identified.
- Supplement or preparation
- Piper methysticum
- Medication ingredient
- lorazepam
Why the precaution applies
NCCIH advises against combining kava with sedatives. Lorazepam can impair alertness and coordination, making this a relevant precaution even without a measured combination risk.
Separate treatments are not a safety test
A small driving study tested kava, oxazepam and placebo on separate occasions. Kava did not impair the tested driving outcomes, but the study did not combine the products or use this medication.
Spacing has not been validated
Bring the kava extract, amount and frequency to the prescriber. Taking the products a few hours apart has not been shown to prevent combined impairment.
Watch for impaired alertness
Lorazepam can affect alertness and coordination. Avoid driving if affected. Seek urgent help for severe difficulty waking or breathing, and tell the prescriber about alcohol, opioids and all other sedating products.
Evidence and practical considerations
Side effects & toxicity
Conditional avoid/review precaution follows kava guidance and the exact medication CNS effects; no measured exact-pair risk magnitude.
- Exact scope
- Oral Piper methysticum; extract, dose and other sedatives must be identified. with Exact oral lorazepam tablets. Rapid conjugation to lorazepam glucuronide, which has no demonstrable CNS activity in animals. Oral tablet scope; injected lorazepam is not assigned the same supplement evidence.
- Medication form and route
- oral
- Timing or duration
- Source-specific single-dose, repeated-dose and observational exposures distinguished.
What remains uncertain
- A separate-dose oxazepam comparison is not a combination study. No exact protective spacing interval or universally safe kava dose.
Factors that may matter: preparation and plant part; clinical indication; dose; other medicines; baseline alertness.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed oral lorazepam.
Can impair alertness and coordination; other CNS depressants can increase impairment. Opioid combinations have a specific respiratory-depression warning. Dependence and withdrawal require supervised changes. Rapid conjugation to lorazepam glucuronide, which has no demonstrable CNS activity in animals. Oral tablet scope; injected lorazepam is not assigned the same supplement evidence.
How this applies: Exact IN and labeled oral formulation; route, salt and metabolite distinctions retained.
No quantified risk for every herb or universal protective spacing interval. Opioid-specific evidence does not prove equal botanical respiratory risk.
Source 2: official guidance
nccih.nih.gov · Source check Sep 10, 2026
Population: People considering the specified supplement.
Advises against use with sedative substances. Kava may cause dizziness and has been linked to rare severe liver injury, including with different extraction methods.
How this applies: Preparation-specific context; not a directly measured lorazepam interaction.
Not a lorazepam study. Intrinsic liver risk does not establish added lorazepam hepatotoxicity; preparation and co-exposure vary.
Source 3: original human study
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Twenty-two adults in a randomized crossover driving study.
Medicinal-dose kava did not significantly impair driving outcomes; oxazepam impaired some outcomes.
How this applies: Apply only to exact medication, preparation and study exposure; comparator treatment is not co-use.
Not combined administration or evidence that all kava preparations lack impairment.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Current exact available claims adjudicated using original captures and explicit identity and comparator limits. | |
| Research summary published |
Article revision: 03593bade983be1a
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.