SeriousCaution
Ginkgo Biloba
Ginkgo has seizure case reports, and clozapine has a dose-related seizure boxed warning.
Recommendation: Avoid ginkgo in patients taking clozapine, especially at higher clozapine doses or with any seizure risk factor.
Clozapine
Prescription ·Strong evidence ·Reviewed May 2026
Clozapine is an atypical antipsychotic reserved for treatment-resistant schizophrenia and for reducing recurrent suicidal behavior in schizophrenia or schizoaffective disorder. It has unique efficacy but multiple boxed warnings, including severe neutropenia, orthostatic hypotension with bradycardia and syncope, seizures, myocarditis or cardiomyopathy, and increased mortality in elderly patients with dementia-related psychosis. ANC monitoring remains required by prescribing information even though FDA removed the Clozapine REMS program effective June 13, 2025.
What it's good for
The bottom line
Evidence rating strong. Most-documented uses: treatment-resistant schizophrenia after inadequate response to standard antipsychotics, reduction in recurrent suicidal behavior in schizophrenia or schizoaffective disorder, may reduce aggression or severe psychotic symptoms in selected refractory cases. 3 sources indexed (1988–2026), with 4 interaction records on file.
The science
How it works, mechanistically.
Core mechanism
Clozapine has complex receptor pharmacology, including dopamine D2/D4, serotonin 5-HT2A/2C, muscarinic, histamine H1, and alpha-adrenergic effects. Its antipsychotic efficacy in treatment resistance is not explained solely by D2 blockade and may involve broader dopaminergic, serotonergic, glutamatergic, and cholinergic modulation. CYP1A2 is the main metabolic pathway, with contributions from CYP3A4 and CYP2D6; inflammation, smoking changes, and inhibitors can substantially alter exposure.1,2
Class
Atypical antipsychotic for treatment-resistant schizophrenia
Dosing
Dosing & protocol.
Common range
Start 12.5 mg once or twice daily and titrate slowly. Common target range is 300-450 mg/day in divided doses; maximum recommended dose is 900 mg/day.
Recommended form
Oral tablet, orally disintegrating tablet, or oral suspension with mandatory ANC monitoring
May be taken with or without food. Restarting after an interruption requires retitration to reduce severe hypotension, bradycardia, and syncope risk.
Safety
Full safety detail.
Side effects
- Sedation
- Sialorrhea
- Constipation and ileus
- Weight gain
- Hyperglycemia and dyslipidemia
- Orthostatic hypotension
- Tachycardia
- Severe neutropenia
- Seizures, dose-related
- Myocarditis, pericarditis, or cardiomyopathy
- Fever
- Neuroleptic malignant syndrome
- Pulmonary embolism
Contraindications
- Hypersensitivity to clozapine1,2
- Do not initiate when baseline ANC is below prescribing-information thresholds2,3
- History of clozapine-induced agranulocytosis or severe granulocytopenia unless benefits clearly justify specialist-supervised rechallenge1,2
- Paralytic ileus
- Use extreme caution with uncontrolled epilepsy, myocarditis history, severe cardiac disease, or severe constipation
Interactions
Interaction records.
ModerateCaution
Melatonin
Melatonin can add to clozapine-related sedation, dizziness, and impaired coordination.
Recommendation: Use cautiously and monitor next-day sedation, falls, and confusion.
SeriousConflict
St. John's Wort
St. John's Wort induces drug-metabolizing enzymes and transporters and may lower exposure to some antipsychotics or destabilize psychiatric treatment.
Recommendation: Avoid St. John's Wort unless the psychiatric prescriber explicitly approves and clozapine response is monitored closely.
ModerateCaution
Ashwagandha
Ashwagandha can be sedating in some patients and may add to clozapine-related somnolence or orthostatic symptoms.
Recommendation: Avoid during clozapine initiation and use cautiously if stable; monitor for sedation and falls.
Sources
Sources, by evidence tier.
Numbered references. Citations throughout the page link here.
Randomized controlled trials
1- 1Clozapine for treatment-resistant schizophreniaNeeds reviewNo linkKane J, Honigfeld G, Singer J, Meltzer H · Archives of General Psychiatry · 1988
Pivotal trial established clozapine efficacy in treatment-resistant schizophrenia compared with chlorpromazine plus benztropine.
Reference material
2- 2CLOZAPINE tablets, US Prescribing InformationNeeds reviewURLU.S. National Library of Medicine · DailyMed · 2026
Current labeling describes boxed warnings, ANC thresholds, slow titration, restart instructions, and serious constipation risk.
- 3FDA removes risk evaluation and mitigation strategy (REMS) program for the antipsychotic drug ClozapineNeeds reviewURLU.S. Food and Drug Administration · FDA Drug Safety and Availability · 2025
FDA eliminated REMS requirements effective June 13, 2025 while preserving ANC monitoring recommendations in labeling.
Keep exploring
Deep dives & adjacent profiles.
This page is educational. Do not start, stop, or change a supplement or medication based on it without checking with a qualified healthcare professional.
Use this with your stack
Clozapine in NutriStack.
Add it to your stack, see how it interacts with everything else you take, and get a Stack Score that updates the moment it does.