Fluoxetine and Iloperidone interaction
Fluoxetine and Iloperidone: 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 Iloperidone (FANAPT) label · effective 2026-05-06
Avoid the use of FANAPT in combination with any other drugs that prolong the QT interval [see Warnings and Precautions (5.3) ] .
…prolong QTc including Class 1A (e.g., quinidine, procainamide) or Class III (e.g., amiodarone, sotalol) antiarrhythmic medications, antipsychotic medications (e.g., 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).
Table 7: Clinically Important Drug Interactions with FANAPT Strong CYP2D6 Inhibitors Clinical Impact Coadministration of fluoxetine with iloperidone increased exposure (area under curve, [AUC]) of iloperidone and its metabolite P88, by about 2- to 3- fold, and decreased the AUC of its metabolite P95 by one-half [see Clinical Pharmacology (12.3 , 12.5) ] .
Intervention Reduce the dose of FANAPT by one-half when administered with strong CYP2D6 inhibitors.
When a strong CYP2D6 inhibitor is withdrawn from the combination therapy, the iloperidone dose should be returned to the previous level [see Dosage and Administration (2.4) ] .
From the Fluoxetine (Prozac) label · effective 2026-01-08
Use with caution in combination with other drugs that prolong the QT interval ( 4.2 , 5.11 , 7.7 , 7.8 ) 7.1 Monoamine Oxidase Inhibitors (MAOI) [See Dosage and Administration ( 2.9 , 2.10 ), Contraindications ( 4.1 ), and Warnings and Precautions ( 5.2 )] .
Coadministration of fluoxetine with other drugs that are metabolized by CYP2D6, including certain antidepressants (e.g., TCAs), antipsychotics (e.g., phenothiazines and most atypicals), and antiarrhythmics (e.g., propafenone, flecainide, and others) should be approached with caution.
These include specific antipsychotics (e.g., ziprasidone, iloperidone, chlorpromazine, mesoridazine, droperidol,); specific antibiotics (e.g., erythromycin, gatifloxacin, moxifloxacin, sparfloxacin); Class 1A antiarrhythmic medications (e.g., quinidine, procainamide); Class III antiarrhythmics (e.g., amiodarone, sotalol); and others (e.g., pentamidine, levomethadyl…
Antipsychotics: Potential for elevation of haloperidol and clozapine levels ( 7.7 )
Antipsychotics — Some clinical data suggests a possible pharmacodynamic and/or pharmacokinetic interaction between SSRIs and antipsychotics.
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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.