Olanzapine

For an informed discussion with your doctor or pharmacist. This information collection is not a clinically validated interaction checker. Missing data do not establish safety. Do not change or stop prescribed medicines on the basis of this information. The findings apply to the specific conditions studied; laboratory and animal studies cannot be directly extrapolated to humans.

Active substance: Olanzapine

Examples of brand names: Zyprexa [EU/DE]

ATC code: N05AH03

Main use (for orientation): Schizophrenia; bipolar disorder

Documented research summary

Controlled THC challenge in 49 men: olanzapine did not statistically significantly reduce the THC-induced increase in the PANSS positive subscale in the overall sample (p=0.066); only the responder analysis was significant. A small phase I lipidomics study with CBD 800 mg/day reports metabolic biomarker changes, not a verified olanzapine pharmacokinetic effect size. The delirium case involving olanzapine pamoate and a higher paliperidone dose in a cannabis smoker is highly confounded.

Uncertainties and limitations

CBD lipidomics study: 38 people in total across five groups, short duration and surrogate markers. No general protection against THC effects. Do not extrapolate the depot case to oral formulation.

Separately recorded findings

1 separately recorded finding. Each statement applies to its documented study context.

Tobacco smoke (context, not a cannabinoid interaction) – clinical signals

Finding ID: B0092

Type of result: Context-specific finding; read the limitations

Observation: Extrapyramidal symptoms after reducing tobacco smoking.

Mechanism: Less smoke-induced induction after reducing tobacco use

Study type: Two case reports; smoking/tobacco context

Context studied: Second case in the publication.

Clinical interpretation: Individual medical / pharmaceutical assessment; do not use as dosage instructions

Limitations and uncertainties: No isolated cannabis evidence; identify as a context record, not a cannabinoid pair.

Original sources for this finding: Tobacco and cannabis smoking cessation can lead to intoxication with clozapine or olanzapine [EX04]

References and access status

[CA_L_D0119] ZYPREXA (OLANZAPINE) TABLET ZYPREXA ZYDIS (OLANZAPINE) TABLET, ORALLY DISINTEGRATING ZYPREXA INTRAMUSCULAR (OLANZAPINE) INJECTION, POWDER, FOR SOLUTION [H2-PHARMA LLC]

Original source / bibliographic reference

Authors: H2-Pharma LLC

Year: 2026

Source type: Current published human-use SPL / product information

Source access – 23 October 2026: Source destination was accessible when checked.

Bibliographic attribution or source identity cross-checked.

[CA_P_22596206] Does olanzapine inhibit the psychomimetic effects of Δ⁹-tetrahydrocannabinol?

Original source / bibliographic reference

Authors: Kleinloog D, Liem-Moolenaar M, Jacobs G, Klaassen E, de Kam M, Hijman R, van Gerven J.

Year: 2012

Source type: Research Support, Non-U.S. Gov't; Randomized Controlled Trial; Journal Article

DOI: 10.1177/0269881112446534

PMID: 22596206

Source access – 23 October 2026: Source destination was accessible when checked.

Bibliographic attribution or source identity cross-checked.

DOI – publisher access (access restrictions may apply)

[CA_P_38950483] Alterations to sphingolipid metabolism from antipsychotic administration in healthy volunteers are restored following the use of cannabidiol.

Original source / bibliographic reference

Authors: Jieu B, Sykorova EB, Rohleder C, Marcolini E, Hoffmann AE, Koethe D, Leweke FM, Couttas TA.

Year: 2024

Source type: Research Support, Non-U.S. Gov't; Clinical Trial, Phase I; Randomized Controlled Trial; Journal Article

DOI: 10.1016/j.psychres.2024.116005

PMID: 38950483

Source access – 23 October 2026: Direct retrieval could not be fully verified; availability remains unresolved.

Bibliographic attribution or source identity cross-checked.

DOI – publisher access (access restrictions may apply)

[CA_P_27335358] Delirium with anticholinergic symptoms after a combination of paliperidone and olanzapine pamoate in a patient known to smoke cannabis: an unfortunate coincidence.

Original source / bibliographic reference

Authors: Kokalj A, Rijavec N, Tavčar R.

Year: 2016

Source type: Journal Article; Case Reports; case-report

DOI: 10.1136/bcr-2016-214806

PMID: 27335358

Source access – 23 October 2026: Source destination was accessible when checked.

Bibliographic attribution or source identity cross-checked.

DOI – publisher access (access restrictions may apply)

[EX04] Tobacco and cannabis smoking cessation can lead to intoxication with clozapine or olanzapine

Original source / bibliographic reference

Authors: Zullino DF; Delessert D; Eap CB; Preisig M; Baumann P

Year: 2002

Source type: Two case reports; smoking/tobacco context

DOI: 10.1097/00004850-200205000-00008

PMID: 11981356

Source access – 23 October 2026: Source destination was accessible when checked.

Bibliographic attribution or source identity cross-checked.

DOI – publisher access (access restrictions may apply)

Research as of 23 October 2026. Not all original full texts could be reviewed in full. Source accessibility and the strength of scientific evidence must be assessed separately. An accessible link does not establish medical approval; a bibliographic record with an abstract does not replace the original full text.

Drug search and explanation of the evidence · Guide: cannabinoids and medicines · Author and responsibility