Isoniazid and Olanzapine and fluoxetine interaction
Isoniazid and Olanzapine and fluoxetine: the Olanzapine and fluoxetine prescribing label flags 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 Olanzapine and fluoxetine label · effective 2026-03-31
Monoamine Oxidase Inhibitors (MAOI) : Because of the risk of serotonin syndrome, do not use MAOIs intended to treat psychiatric disorders with olanzapine and fluoxetine capsules or within 5 weeks of stopping treatment with olanzapine and fluoxetine capsules.
Do not use olanzapine and fluoxetine capsules within 14 days of stopping an MAOI intended to treat psychiatric disorders.
Do not use thioridazine within 5 weeks of discontinuing olanzapine and fluoxetine capsules ( 4.2 , 5.20 , 7.7 , 7.8 ) 4.1 Monoamine Oxidase Inhibitors (MAOIs) The use of MAOIs intended to treat psychiatric disorders with olanzapine and fluoxetine capsules or within 5 weeks of stopping treatment with olanzapine and fluoxetine capsules is contraindicated because…
The use of olanzapine and fluoxetine capsules within 14 days of stopping an MAOI intended to treat psychiatric disorders is also contraindicated [see Dosage and Administration ( 2.4 ) and Warnings and Precautions ( 5.6 )] .
Starting olanzapine and fluoxetine capsules in a patient who is being treated with MAOIs such as linezolid or intravenous methylene blue is also contraindicated because of an increased risk of serotonin syndrome [see Dosage and Administration ( 2.5 ) and Warnings and Precautions ( 5.6 )] .
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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.