Fosnetupitant and Cariprazine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 16, 2026 · Source data updated Jul 16, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fosnetupitant
No brand names on recordCariprazine
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Here's what's going on. Your body uses a liver enzyme called CYP3A4 to break down cariprazine (Vraylar). Fosnetupitant slows that enzyme down. So while you're taking both, cariprazine and its active breakdown product can build up higher than usual in your body.
That means you could feel more of cariprazine's effects and side effects, like restlessness, sleepiness, tremor, or trouble sitting still. The good news is this is very manageable. Your care team already knows how to adjust your cariprazine dose so the two medicines work together safely. Please don't stop or change anything on your own, and let your pharmacist or doctor know you're taking both.
Mechanism: Fosnetupitant (moderate CYP3A4 inhibitor) reduces CYP3A4-mediated metabolism of cariprazine, a CYP3A4 substrate, increasing exposure to cariprazine and its long-acting active metabolite didesmethylcariprazine (DDCAR). Neither is a prodrug requiring this enzyme for activation, so the effect is increased exposure and PD effect.
Severity: Major. Evidence: Probable.
- Watch for dose-related adverse effects: EPS/akathisia, somnolence, sedation.
- Dose adjust per labeling: initiate at 1.5 mg PO every other day; stable patients on 1.5 or 3 mg daily reduce to 1.5 mg every other day; those on 4.5 or 6 mg daily reduce to 1.5 mg once daily.
- On inhibitor discontinuation, cariprazine dose may be increased per clinical response.
What happens
Increased cariprazine and its major active metabolite (didesmethylcariprazine (DDCAR)) exposure
Interaction Deep Dive
Giving cariprazine (which is a CYP3A4 substrate) together with a moderate CYP3A4 inhibitor can raise the levels of cariprazine as well as its active metabolite, didesmethylcariprazine. If cariprazine is being started in a patient already receiving a moderate CYP3A4 inhibitor for schizophrenia or bipolar mania, begin with 1.5 mg orally every other day; this can be raised to 1.5 mg orally every other day, if required, guided by how the patient responds clinically and tolerates the drug. For a patient on a moderate CYP3A4 inhibitor being treated for bipolar depression or receiving adjunctive therapy for MDD, the dose is 1.5 mg orally every other day. When a moderate CYP3A4 inhibitor is added to an already stable cariprazine regimen: for a patient currently taking 1.5 or 3 mg once daily, modify the cariprazine dose to 1.5 mg orally every other day upon starting the moderate inhibitor. For a patient currently taking cariprazine 4.5 or 6 mg once daily, change the cariprazine dose to 1.5 mg orally once daily when the moderate inhibitor is begun. Should the moderate CYP3A4 inhibitor be stopped, an increase in the cariprazine dosage may be required, determined by clinical response and tolerability1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of cariprazine
How to manage this interaction
This is manageable with dose tailoring and monitoring by your care team. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise.
- Your cariprazine dose may be adjusted and individualized. Typically it is lowered (for example, to a smaller dose or every-other-day dosing) while you are on the CYP3A4 inhibitor.
- Your team may monitor you more closely for side effects like restlessness, tremor, or drowsiness.
- If the inhibitor is later stopped, your cariprazine dose may be increased again.
What to do: Tell your pharmacist and prescriber you take both, and report any new or worsening side effects.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In drug interaction studies, giving cariprazine 1.5 mg/day together with erythromycin (a moderate CYP3A4 inhibitor) 500 mg twice daily for 21 days led to an increase in cariprazine AUC (0 to 24 hours) and Cmax of about 50% 1. In one study that enrolled only White males receiving cariprazine 1.5 mg/day and erythromycin 500 mg twice daily (n=40), AUCs rose by 38% (cariprazine), 11% (desmethylcariprazine, an active metabolite), and 60% (didesmethylcariprazine, an active metabolite), while Cmax rose by 34%, 16%, and 62%, respectively. Tmax was not altered by concurrent administration of erythromycin 2.
Common questions
Can I take Fosnetupitant and Cariprazine together?
Fosnetupitant can raise cariprazine levels by slowing its breakdown, so your care team will likely lower or space out your cariprazine dose and watch for side effects. Keep taking both as prescribed and report any restlessness, tremor, or drowsiness. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fosnetupitant and Cariprazine interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Fosnetupitant and Cariprazine interaction managed?
This is manageable with dose tailoring and monitoring by your care team. Keep taking both medicines exactly as prescribed unless your prescriber tells you otherwise. Your cariprazine dose may be adjusted and individualized. Typically it is lowered (for example, to a smaller dose or every-other-day dosing) while you are on the CYP3A4 inhibitor. Your team may monitor you more closely for side effect… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Fosnetupitant or Cariprazine need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: VRAYLAR(R) oral capsules, cariprazine oral capsules. AbbVie Inc. (per FDA), North Chicago, IL, 2024. DailyMed
- Szabo M, Hujber Z, Harsanyi J, et al: Coadministration of cariprazine with a moderate CYP3A4 inhibitor in patients with schizophrenia: implications for dose adjustment and safety monitoring. Clin Pharmacokinet 2024; 63(10):1501-1510. PubMed
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