Drug Interaction Report

Olanzapine and Diazepam Rectal: Interaction Details

A pharmacist-reviewed analysis of the Olanzapine and Diazepam Rectal interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Olanzapine

No brand names on record
+

Diazepam Rectal

Diastat Diastat®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
How we grade severity & evidence

Severity levels

  • Contraindicated: These should generally not be used together.
  • Major: Potentially serious — often needs a change or close monitoring.
  • Moderate: Can be significant — usually manageable with monitoring.
  • Minor: Usually limited clinical impact.

Evidence grades

  • Established: Well documented — supported by controlled studies or strong clinical data.
  • Probable: Good supporting evidence, though not definitively proven.
  • Suspected: Some evidence suggests this interaction, but it is not well established.
  • Possible: Limited or conflicting evidence; the interaction may occur.
  • Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.

Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.

Of 101 documented Olanzapine interactions, 98 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
theoretical
Severity
Major

What happens

An increased risk of CNS depression, orthostatic hypotension, potentiation of excessive sedation and cardiorespiratory depression

Interaction Deep Dive

The concomitant use of intramuscularly administered OLANZapine and parenteral benzodiazepines like diazePAM is not recommended due to additive CNS depression1. Additionally, coadministration of diazePAM with OLANZapine may potentiate orthostatic hypotension. Also, use caution if the concomitant administration of OLANZapine and other CNS-active drugs like diazePAM is required 23. In evaluating individual cases, consider using lower initial doses of the concomitantly administered drugs, using conservative titration schedules, and monitoring clinical status 3.

Why it happens (mechanism)

Additive CNS depression

Common questions

Can I take Olanzapine and Diazepam Rectal together?

An increased risk of CNS depression, orthostatic hypotension, potentiation of excessive sedation and cardiorespiratory depression Always confirm with your pharmacist or prescriber before making any change.

How serious is the Olanzapine and Diazepam Rectal interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Olanzapine or Diazepam Rectal need adjusting while I take them together?
  • What symptoms should prompt me to call you or my prescriber right away?
  • Does the timing of my doses matter for this combination?
  • Is there a safer alternative to one of these medications for me?

References (3)

  1. Product Information: ZYPREXA(R) IntraMuscular IM injection, olanzapine IM injection. Lilly USA, LLC (per manufacturer), Indianapolis, IN, 2011.
  2. Product Information: LYBALVI(R) oral tablets, olanzapine samidorphan oral tablets. Alkermes Inc (per FDA), Waltham, MA, 2024. DailyMed
  3. Product Information: SYMBYAX(R) oral capsules, olanzapine fluoxetine oral capsules. Lilly USA LLC (per FDA), Indianapolis, IN, 2023.
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Olanzapine

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All Olanzapine interactions (101)
Also serious with: Metoclopramide Injection Metoclopramide Nasal Spray Morphine Injection Encorafenib
Diazepam Rectal

Keep reading about Diazepam Rectal

All Diazepam Rectal interactions (281) Diazepam Rectal drug information
Also serious with: Isocarboxazid Flumazenil Ensitrelvir Zuranolone
Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Olanzapine + Activated Charcoal Indian Snakeroot Lithium Rauvolfia Vomitoria 1,3-dmaa 5-htp Acacia Rigidula Acetyl-l-carnitine + 152 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.