Olanzapine and fluoxetine and Quetiapine interaction

Olanzapine and fluoxetine and Quetiapine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

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

Major

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,…

Warnings and precautionsnames Olanzapine and fluoxetineView label on DailyMed
Moderate

• Anticholinergic (antimuscarinic) Effects: Use with caution with other anticholinergic drugs and in patients with urinary retention, prostatic hypertrophy, or constipation (5.20)

Warnings and precautionsby drug classView label on DailyMed
Moderate

It is generally believed (though not established in controlled trials) that treating such an episode with an antidepressant alone may increase the likelihood of precipitation of a mixed/manic episode in patients at risk for bipolar disorder.

Warnings and precautionsby drug classView label on DailyMed
Moderate

Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever, and primary central nervous system (CNS) pathology.

Warnings and precautionsby drug classView label on DailyMed
Moderate

…Class 1A antiarrythmics (e.g., quinidine, procainamide) or Class III antiarrythmics (e.g., amiodarone, sotalol), antipsychotic medications (e.g., ziprasidone, chlorpromazine, thioridazine), antibiotics (e.g., gatifloxacin, moxifloxacin), or any other class of medications known to prolong the QTc interval (e.g., pentamidine, levomethadyl acetate, methadone).

Warnings and precautionsby drug classView label on DailyMed

From the Olanzapine and fluoxetine label · effective 2026-03-31

Moderate

Use olanzapine and fluoxetine capsules with caution in combination with other drugs that prolong the QT interval ( 4.2 , 5.20 , 7.7 , 7.8 ) 7.1 Monoamine Oxidase Inhibitors (MAOIs) [See Dosage and Administration ( 2.4 , 2.5 ), Contraindications ( 4.1 ), and Warnings and Precautions ( 5.6 )] .

Drug interactionsby drug classView label on DailyMed

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Not 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.