Ritonavir and Vilazodone interaction
Ritonavir and Vilazodone: 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 Ritonavir (Norvir) label · effective 2026-07-23
Antidepressants: nefazodone, selective serotonin reuptake inhibitors (SSRIs): e.g. fluoxetine, paroxetine, tricyclics: e.g. amitriptyline, nortriptyline ↑ antidepressants A dose decrease may be needed for these drugs when co-administered with ritonavir.
Antidepressant: bupropion ↓ bupropion ↓ active metabolite, hydroxybupropion Patients receiving ritonavir and bupropion concurrently should be monitored for an adequate clinical response to bupropion.
Antidepressant: desipramine ↑ desipramine Dosage reduction and concentration monitoring of desipramine is recommended.
Antidepressant: trazodone ↑ trazodone Adverse events of nausea, dizziness, hypotension and syncope have been observed following co-administration of trazodone and NORVIR.
From the Vilazodone (VIIBRYD) label · effective 2023-10-01
CYP3A4 Inhibitors: The VIIBRYD dose should not exceed 20 mg once daily when co-administered with strong CYP3A4 inhibitors ( 2.4 , 7 ).
CYP3A4 Inducers: Consider increasing VIIBRYD dosage by 2-fold, up to 80 mg once-daily over 1 to 2 weeks when used concomitantly with strong CYP3A4 inducers for greater than 14 days ( 2.4 , 7 ).
Strong CYP3A4 Inhibitors (e.g., itraconazole, clarithromycin, voriconazole) The concomitant use of VIIBRYD and strong CYP3A4 inhibitors increased the exposure of vilazodone compared to the use of VIIBRYD alone [see Clinical Pharmacology ( 12.3 )].
The VIIBRYD dose should not exceed 20 mg once daily with the concomitant use of a strong CYP3A4 inhibitor [see Dosage and Administration ( 2.4 ) , Clinical Pharmacology ( 12.3 ) ] .
Strong CYP3A4 Inducers (e.g., carbamazepine, phenytoin, rifampin) The concomitant use of VIIBRYD and strong CYP3A4 inducers decreased the exposure of vilazodone compared to the use of VIIBRYD alone [see Clinical Pharmacology ( 12.3 )].
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.