Paritaprevir 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
Paritaprevir
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. Cariprazine (Vraylar) is broken down in your body by an enzyme called CYP3A4. Paritaprevir, part of your hepatitis C treatment, strongly blocks that enzyme. When the enzyme is blocked, cariprazine and its active byproduct build up. In studies with a similar strong blocker, the amount in the body roughly doubled.
More cariprazine can mean more side effects, like restlessness, trouble sleeping, drowsiness, muscle stiffness, or shakiness. The good news is your care team can manage this easily by lowering your cariprazine dose or spacing it out further. Please don't change anything on your own. Just talk with your pharmacist or doctor so they can adjust it for you.
Mechanism: Paritaprevir is a strong CYP3A4 inhibitor; cariprazine is a CYP3A4 substrate (active metabolite didesmethylcariprazine). Inhibition reduces cariprazine clearance, increasing exposure. Neither drug is a prodrug in a way that reverses this; effect is increased cariprazine exposure.
Magnitude: Ketoconazole increased cariprazine AUC and Cmax by ~100%. Evidence: probable. Severity: major.
Management (per labeling):
- Initiating cariprazine on a strong inhibitor (schizophrenia/bipolar mania): 1.5 mg every 3 days, may increase to 1.5 mg every other day per tolerability.
- Bipolar depression/adjunct MDD: 1.5 mg every 3 days.
- Adding inhibitor to stable 1.5 or 3 mg daily: reduce to 1.5 mg every 3 days; on 4.5 or 6 mg daily: reduce to 1.5 mg every other day.
- On inhibitor discontinuation, cariprazine dose may need increasing per response.
What happens
Increased exposure to cariprazine and its active metabolite, didesmethylcariprazine
Interaction Deep Dive
Taking cariprazine (which is metabolized by CYP3A4) together with a potent CYP3A4 inhibitor can raise the levels of cariprazine as well as its active metabolite, didesmethylcariprazine. In drug interaction trials, giving cariprazine alongside ketoconazole (a strong CYP3A4 inhibitor) produced roughly a 100% rise in both AUC and Cmax. As a result, when beginning cariprazine in a patient already receiving a strong CYP3A4 inhibitor (for schizophrenia or bipolar mania), the recommended starting dose is 1.5 mg orally every 3 days, which may be raised to 1.5 mg orally every other day if warranted, guided by clinical response and how well it is tolerated. For patients on a strong CYP3A4 inhibitor being treated for bipolar depression or receiving cariprazine as adjunctive therapy for MDD, the dose is 1.5 mg orally every 3 days. If a strong CYP3A4 inhibitor is added to an established cariprazine regimen, dose modifications apply: patients currently on 1.5 or 3 mg once daily should have their cariprazine changed to 1.5 mg orally every 3 days when the strong inhibitor is started, while those on 4.5 or 6 mg once daily should be switched to 1.5 mg orally every other day. Once the strong CYP3A4 inhibitor is stopped, an increase in the cariprazine dose may be warranted according to clinical response and tolerability1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of cariprazine
How to manage this interaction
Keep taking both medications as prescribed unless your care team tells you otherwise. This combination is well recognized and can be managed with dose adjustments.
- Your prescriber will typically lower your cariprazine dose or space it out (for example, taking it less often) while you are on paritaprevir.
- If cariprazine is being started while you are already on the inhibitor, they will begin at a reduced dose.
- Your team may monitor you more closely for side effects such as restlessness, stiffness, or drowsiness.
- When the hepatitis C treatment ends, your cariprazine dose may be increased again based on how you respond.
Ask your pharmacist or doctor to confirm the right dosing plan for you.
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 0.5 mg/day together with ketoconazole 400 mg/day led to an increase in total cariprazine AUC and Cmax of about 100% 1.
Common questions
Can I take Paritaprevir and Cariprazine together?
Paritaprevir strongly blocks the enzyme that clears cariprazine, so cariprazine levels can roughly double and cause more side effects. Your care team can manage this safely by lowering or spacing out your cariprazine dose, so talk with your pharmacist or doctor before changing anything. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Paritaprevir 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 Paritaprevir and Cariprazine interaction managed?
Keep taking both medications as prescribed unless your care team tells you otherwise. This combination is well recognized and can be managed with dose adjustments. Your prescriber will typically lower your cariprazine dose or space it out (for example, taking it less often) while you are on paritaprevir. If cariprazine is being started while you are already on the inhibitor, they will begin at a r… 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 Paritaprevir 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 (1)
- Product Information: VRAYLAR(R) oral capsules, cariprazine oral capsules. AbbVie Inc. (per FDA), North Chicago, IL, 2024. DailyMed
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