Olanzapine and fluoxetine and Phentermine and topiramate interaction
Olanzapine and fluoxetine and Phentermine and topiramate: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Phentermine and topiramate label · effective 2026-05-18
The concomitant use of alcohol or central nervous system (CNS) depressant drugs with phentermine and topiramate extended-release capsules may potentiate CNS depression or other centrally mediated effects of these agents, such as dizziness, cognitive adverse reactions, drowsiness, light-headedness, impaired coordination, and somnolence.
CNS Depressants Including Alcohol Clinical Impact The concomitant use of alcohol or CNS depressant drugs (e.g., barbiturates, benzodiazepines, and sleep medications) with phentermine or topiramate may potentiate CNS depression such as dizziness or cognitive adverse reactions, or other centrally mediated effects of these agents.
CNS Depressants Including Alcohol : May potentiate CNS depressant effects.
From the Olanzapine and fluoxetine label · effective 2026-03-31
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.
Carbamazepine : Potential for elevated carbamazepine levels and clinical anticonvulsant toxicity ( 7.7 )
Phenytoin : Potential for elevated phenytoin levels and clinical anticonvulsant toxicity ( 7.7 )
Carbamazepine — Patients on stable doses of carbamazepine have developed elevated plasma anticonvulsant concentrations and clinical anticonvulsant toxicity following initiation of concomitant fluoxetine treatment.
Other Serotonergic Drugs The concomitant use of serotonergic drugs (including other SSRIs, SNRIs, triptans, tricyclic antidepressants, opioids, lithium, buspirone, amphetamines, tryptophan, and St.
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.