The short answer
There is not enough direct evidence to say that American skullcap increases sedation with clozapine. One small skullcap study found no reduction in energy or cognition, and another reported no adverse effects. Neither tested this combination, so these findings do not establish that co-use is safe.
What this answer covers
Scutellaria lateriflora (American skullcap) oral preparations, specifically characterized aerial-part extracts where stated. Scutellaria baicalensis and isolated flavonoids are distinct.
- Supplement or preparation
- Scutellaria lateriflora
- Medication ingredient
- clozapine
The direct interaction is uncertain
Clozapine can cause sedation, but that alone does not prove that every herb used for sleep adds to it. No direct clozapine and American skullcap clinical study was identified in the targeted search. The size and likelihood of an interaction remain unknown.
What the small studies found
A 43-person study reported improved mood without reduced energy or cognition. A later 66-person insomnia study reported better subjective sleep and no adverse effects with a characterized extract. Both had limitations, including carryover effects, and the later study excluded schizophrenia. Neither establishes clozapine combination safety.
American skullcap is a specific plant
These findings concern Scutellaria lateriflora. Chinese skullcap, Scutellaria baicalensis, is a different species, and an isolated constituent is a different exposure. The 2025 study used a defined aerial-part extract standardized to 10% baicalin; that result cannot automatically be assigned to every skullcap product.
Avoid assuming that unknown means safe
Discuss the exact product with the clozapine team before adding it for sleep. If you feel drowsy or unsteady, avoid driving and hazardous tasks and seek advice about troublesome symptoms. There is no established dose gap or clozapine dose change that resolves the evidence gap.
Evidence and practical considerations
Side effects & toxicity
An increased clozapine sedation or CNS-depression risk from American skullcap remains unestablished.
- Exact scope
- Scutellaria lateriflora (American skullcap) oral preparations, specifically characterized aerial-part extracts where stated. Scutellaria baicalensis and isolated flavonoids are distinct. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral botanical preparation
What remains uncertain
- No clozapine co-use study; the insomnia trial excluded schizophrenia. Sleep improvement does not establish harmful additive sedation.
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: randomized human trial
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 43 healthy participants, predominantly mildly anxious or less.
No significant between-treatment anxiety difference; mood improved without reduced energy or cognition.
How this applies: Botanical-only evidence; relevance to clozapine requires separate interpretation.
Carryover and baseline group differences; no clozapine use. Findings do not prove absence of interaction.
Source 3: randomized human trial
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 66 adults with primary insomnia; schizophrenia and other psychiatric disorders excluded.
Subjective sleep outcomes improved and no adverse effects were reported.
How this applies: Botanical-only evidence; relevance to clozapine requires separate interpretation.
Subjective endpoints, carryover effect, single center, product supplied free; no clozapine or schizophrenia applicability.
Research assessment: · Open full citations ↗
Side effects & toxicity
Skullcap trials reporting no reduced energy or cognition or no adverse effects cannot establish safety for people taking clozapine.
- Exact scope
- Scutellaria lateriflora (American skullcap) oral preparations, specifically characterized aerial-part extracts where stated. Scutellaria baicalensis and isolated flavonoids are distinct. with Oral clozapine, RxNorm 2626 IN.
- Medication form and route
- oral clozapine; oral botanical preparation
What remains uncertain
- Small selected populations, carryover effects and different formulations; no pair-specific safety comparison.
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: 43 healthy participants, predominantly mildly anxious or less.
No significant between-treatment anxiety difference; mood improved without reduced energy or cognition.
How this applies: Botanical-only evidence; relevance to clozapine requires separate interpretation.
Carryover and baseline group differences; no clozapine use. Findings do not prove absence of interaction.
Source 2: randomized human trial
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 66 adults with primary insomnia; schizophrenia and other psychiatric disorders excluded.
Subjective sleep outcomes improved and no adverse effects were reported.
How this applies: Botanical-only evidence; relevance to clozapine requires separate interpretation.
Subjective endpoints, carryover effect, single center, product supplied free; no clozapine or schizophrenia applicability.
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. | |
| Clarified the study summary and formatted the original citation title for readability. | |
| Research summary published |
Article revision: 74b894c0c8f59973
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.