Doxepin and Olanzapine and fluoxetine interaction
Doxepin and Olanzapine and fluoxetine: both prescribing labels 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 Olanzapine and fluoxetine label · effective 2026-03-31
If concomitant use of olanzapine and fluoxetine capsules with other serotonergic drugs is clinically warranted, patients should be made aware of a potential increased risk for serotonin syndrome, particularly during treatment initiation and dose increases ( 5.6 )
If concomitant use of olanzapine and fluoxetine capsules with other serotonergic drugs is clinically warranted, inform patients of the increased risk for serotonin syndrome and monitor for symptoms.
If serotonin syndrome occurs, consider discontinuation of olanzapine and fluoxetine capsules and/or concomitant serotonergic drugs [see Warnings and Precautions ( 5.6 )] .
Anticholinergic (antimuscarinic) Effects : Use with caution with other anticholinergic drugs and in patients with urinary retention, prostatic hypertrophy, constipation, history of paralytic ileus or related conditions ( 5.21 )
The risk is increased with concomitant use of other serotonergic drugs (including triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, meperidine, methadone, tryptophan, buspirone, amphetamines, and St.
From the Doxepin (Silenor) label · effective 2026-04-21
Potential additive effects when used in combination with CNS depressants or sedating antihistamines.
Although behaviors such as "sleep-driving" may occur with hypnotics alone at therapeutic doses, the use of alcohol and other CNS depressants with hypnotics appears to increase the risk of such behaviors, as does the use of hypnotics at doses exceeding the maximum recommended dose.
When taken with SILENOR, the sedative effects of alcoholic beverages, sedating antihistamines, and other CNS depressants may be potentiated [s ee Warnings and Precautions (5.2) and Drug Interactions (7.3 , 7.4) ].
Patients should be cautioned about potential additive effects of SILENOR used in combination with CNS depressants or sedating antihistamines [s ee Warnings and Precautions (5.2) and Drug Interactions (7.4) ].
CNS Depressants and Sedating Antihistamines: Sedative effects may be increased with doxepin.
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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.