The short answer
Passionflower may affect alertness, but increased sedation with clozapine has not been demonstrated. Two small studies in surgical patients found no increase in sedation compared with placebo. Those results do not establish safety during clozapine treatment, so discuss a sleep product with the prescribing team.
What this answer covers
Passiflora incarnata above-ground herb preparations; other Passiflora species, fruit products and multi-herb blends are separate exposures.
- Supplement or preparation
- Passiflora incarnata
- Medication ingredient
- clozapine
Why caution is still reasonable
Clozapine can cause sedation and impaired coordination. The passionflower monograph cautions that some preparations may impair driving. It also records no reported interactions. These points support caution about alertness without treating a clozapine interaction as proven.
What the human studies found
In one 60-patient surgery study, a single 500 mg passionflower product reduced anxiety without increasing sedation compared with placebo. Another 60-patient study before spinal anesthesia likewise found no significant difference in sedation or psychomotor function. Neither establishes the result when passionflower is used with clozapine.
Match the botanical preparation
The monograph covers Passiflora incarnata herb preparations used by mouth. Evidence from one extract cannot automatically establish the effects of a different species, fruit product or multi-ingredient sleep blend. Product identity and other ingredients matter when reviewing possible drowsiness.
There is no established spacing rule
The reviewed evidence does not establish routine avoidance of all passionflower products or a safe number of hours between doses. Ask the clozapine team before adding a sleep product, and avoid hazardous tasks if alertness is impaired. Do not change clozapine dosing yourself.
Evidence and practical considerations
Side effects & toxicity
Official passionflower driving precautions and clozapine sedation labeling support attention to alertness, not a confirmed additive interaction.
- Exact scope
- Passiflora incarnata above-ground herb preparations; other Passiflora species, fruit products and multi-herb blends are separate exposures. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral botanical preparation
What remains uncertain
- Monograph reports no interactions; it is not evidence of absence or a clozapine trial.
Factors that may matter: exact botanical preparation; other medicines; baseline drowsiness.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed clozapine.
Clozapine can cause sedation and impaired cognitive or motor performance; somnolence and instability can contribute to falls. Severe hepatotoxicity has been reported.
How this applies: Medication-specific safety context only; no direct botanical interaction or automatic dose change is established.
Does not name any of the six botanical counterparties or quantify their combined risks.
Source 2: final regulatory herbal monograph
ema.europa.eu · Source check Sep 10, 2026
Population: Users of specified oral passionflower preparations.
Traditional use for mild stress and sleep; no interactions reported; may impair driving and machinery use.
How this applies: Botanical-only evidence; relevance to clozapine requires separate interpretation.
No direct clozapine evidence. Traditional-use status and absence of reports do not establish combination safety.
Research assessment: · Open full citations ↗
Side effects & toxicity
Two small perioperative trials found no significant increase in sedation with passionflower versus placebo, leaving clozapine-specific effects unknown.
- Exact scope
- Passiflora incarnata above-ground herb preparations; other Passiflora species, fruit products and multi-herb blends are separate exposures. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral botanical preparation
What remains uncertain
- Short-term selected surgical populations; cannot be generalized to chronic clozapine use.
Factors that may matter: exact botanical preparation; other medicines; baseline drowsiness.
Read the supporting source summaries
Source 1: randomized human trial
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 60 patients undergoing ambulatory surgery.
Anxiety was reduced, while sedation scores and recovery measures were similar between groups.
How this applies: Botanical-only evidence; relevance to clozapine requires separate interpretation.
Acute perioperative study, not chronic clozapine co-use. A null sedation result does not establish all formulations are nonsedating.
Source 2: randomized human trial
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 60 adults aged 25-55 undergoing spinal anesthesia.
Sedation, psychomotor function, hemodynamics and side effects did not differ significantly between groups.
How this applies: Botanical-only evidence; relevance to clozapine requires separate interpretation.
No clozapine group and no long-term combination data.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Preparation-specific evidence and uncertainty assessed. | |
| Research summary published |
Article revision: d820f1dd6ce37078
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.