Conivaptan 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
Conivaptan
Cariprazine
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. Cariprazine (Vraylar) is broken down in your body by a liver enzyme called CYP3A4. Conivaptan (Vaprisol) slows that enzyme down. So when you take both, cariprazine and its active breakdown product can build up higher than usual. That can mean more of its effects and more side effects, like restlessness, muscle stiffness, drowsiness, or feeling shaky.
The good news: this is very manageable. Your care team can simply lower your cariprazine dose while you're on conivaptan and watch how you're doing. Please don't stop or change either medicine on your own. Just talk with your pharmacist or doctor so they can tailor the dose for you.
Mechanism: Conivaptan is a moderate CYP3A4 inhibitor; cariprazine is a CYP3A4 substrate. Inhibition reduces metabolism, increasing exposure of cariprazine and its long-acting active metabolite didesmethylcariprazine (DDCAR).
Direction: increased exposure/effect (not a prodrug scenario). Evidence: probable. Severity: major. Onset: unspecified.
Management (per labeling):
- Initiating cariprazine on a moderate inhibitor (schizophrenia/bipolar mania): 1.5 mg every other day, titrate per response/tolerability.
- Bipolar depression or adjunctive MDD: 1.5 mg every other day.
- Stable 1.5 or 3 mg daily, adding inhibitor: reduce to 1.5 mg every other day.
- Stable 4.5 or 6 mg daily: reduce to 1.5 mg daily.
- On inhibitor discontinuation: dose may need to be increased per response.
What happens
Increased cariprazine and its major active metabolite (didesmethylcariprazine (DDCAR)) exposure
Interaction Deep Dive
Taking cariprazine (a CYP3A4 substrate) together with a moderate CYP3A4 inhibitor can raise the exposure 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, then, if warranted by clinical response and tolerability, increase to 1.5 mg orally every other day. For a patient on a moderate CYP3A4 inhibitor being treated for bipolar depression or receiving adjunctive therapy for MDD, use 1.5 mg orally every other day. If instead a moderate CYP3A4 inhibitor is being added for a patient already on a stable cariprazine regimen: for those currently receiving 1.5 or 3 mg once daily, modify the cariprazine dose to 1.5 mg orally every other day when the moderate inhibitor is started; for those currently receiving cariprazine 4.5 or 6 mg once daily, modify the cariprazine dose to 1.5 mg orally once daily when the moderate inhibitor is started. Upon stopping the moderate CYP3A4 inhibitor, the cariprazine dose may require an increase guided by clinical response and tolerability1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of cariprazine
How to manage this interaction
What your care team may do: Because conivaptan can raise cariprazine levels, your prescriber will likely lower your cariprazine dose while you are on both, and adjust it based on how you respond and tolerate it.
- If you are already on cariprazine and conivaptan is being added, your dose may be reduced.
- If cariprazine is being started while you are on conivaptan, it is typically started low.
- When conivaptan is stopped, your cariprazine dose may need to be raised again.
What you should do: Keep taking both exactly as prescribed. Ask your pharmacist or doctor before making any change, and report new restlessness, stiffness, tremor, or drowsiness.
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 roughly 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), and Cmax rose by 34%, 16%, and 62%, respectively. Tmax was not altered by coadministration with erythromycin 2.
Common questions
Can I take Conivaptan and Cariprazine together?
Conivaptan can raise cariprazine levels and side effects, so your care team will likely reduce and individualize your cariprazine dose while you use both. Keep taking both as prescribed and check with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Conivaptan 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 Conivaptan and Cariprazine interaction managed?
What your care team may do: Because conivaptan can raise cariprazine levels, your prescriber will likely lower your cariprazine dose while you are on both, and adjust it based on how you respond and tolerate it. If you are already on cariprazine and conivaptan is being added, your dose may be reduced. If cariprazine is being started while you are on conivaptan, it is typically started low. When co… 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 Conivaptan 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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