Olanzapine and Quetiapine interaction
Olanzapine and Quetiapine: the Quetiapine prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Quetiapine (SEROQUEL XR) label · effective 2026-04-10
Cerebrovascular Adverse Reactions, Including Stroke, in Elderly Patients with Dementia-Related Psychosis In placebo-controlled trials with risperidone, aripiprazole, and olanzapine in elderly subjects with dementia, there was a higher incidence of cerebrovascular adverse reactions (cerebrovascular accidents and transient ischemic attacks), including fatalities,…
• Anticholinergic (antimuscarinic) Effects: Use with caution with other anticholinergic drugs and in patients with urinary retention, prostatic hypertrophy, or constipation (5.20)
Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever, and primary central nervous system (CNS) pathology.
SEROQUEL XR and other antipsychotic drugs should be used cautiously in patients at risk for aspiration pneumonia.
This contributes to anticholinergic adverse reactions when SEROQUEL XR is used at therapeutic doses, taken concomitantly with other anticholinergic medications, or taken in overdose.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.