Amprenavir 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
Amprenavir
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.
You've been prescribed amprenavir (an HIV medicine) along with cariprazine (Vraylar). Amprenavir slows down a liver enzyme called CYP3A4 that your body uses to break down cariprazine. When that enzyme is slowed, cariprazine and its active breakdown product can build up in your body. That means you could feel more of cariprazine's effects and side effects, like restlessness, tremor, drowsiness, or trouble sitting still.
The good news is this is very manageable. Your care team can simply use a lower dose of cariprazine while you're on amprenavir, and adjust it back if amprenavir is stopped. Please don't change anything on your own, just check in with your doctor or pharmacist.
Effect: Amprenavir inhibits CYP3A4, the enzyme responsible for cariprazine metabolism, increasing exposure to cariprazine and its long-acting active metabolite didesmethylcariprazine (DDCAR). Neither drug is a prodrug in a way that reverses this; expect increased PD effect and EPS/sedation risk.
- Direction: increased cariprazine/DDCAR exposure
- Severity/Evidence: major, theoretical
- Management (moderate CYP3A4 inhibitor dosing per label): For schizophrenia/bipolar mania, start 1.5 mg every other day. For bipolar depression/adjunctive MDD, 1.5 mg every other day. If inhibitor added to stable therapy: 1.5 or 3 mg/day becomes 1.5 mg every other day; 4.5 or 6 mg/day becomes 1.5 mg once daily. Increase again when inhibitor stopped.
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 levels of both cariprazine and its active metabolite, didesmethylcariprazine. If cariprazine is being started in a patient already receiving a moderate CYP3A4 inhibitor for schizophrenia or bipolar mania, the recommended starting dose is 1.5 mg by mouth every other day, which may be raised to 1.5 mg orally every other day when necessary, guided by clinical response and how well it is tolerated. For patients on a moderate CYP3A4 inhibitor being treated for bipolar depression or receiving adjunctive therapy for major depressive disorder (MDD), the dose is 1.5 mg orally every other day. When a moderate CYP3A4 inhibitor is added to a patient already stable on cariprazine, dosing should be modified as follows: those taking 1.5 or 3 mg once daily should have their cariprazine reduced to 1.5 mg orally every other day upon starting the inhibitor, while those taking 4.5 or 6 mg once daily should be changed to 1.5 mg orally once daily. Should the moderate CYP3A4 inhibitor later be stopped, an increase in the cariprazine dose may be warranted according to clinical response and tolerability. Furthermore, using cariprazine (a CYP3A4 substrate) together with a CYP3A4 inducer is not advised. The generation and clearance of cariprazine's active metabolites depend on CYP3A4. Because the impact of CYP3A4 inducers on cariprazine exposure has not been studied, the overall effect remains uncertain1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of cariprazine; induction of CYP3A4-mediated metabolism of cariprazine
How to manage this interaction
Keep taking both medications as prescribed. The key here is that your cariprazine dose is tailored while you are on amprenavir.
- Your care team will typically use a lower cariprazine dose (often as little as 1.5 mg every other day, depending on your current dose and condition) while amprenavir is on board.
- If amprenavir is later stopped, your cariprazine dose may be increased back up based on how you respond.
- Watch for and report increased side effects such as restlessness, tremor, muscle stiffness, or drowsiness.
Talk with your pharmacist or prescriber before making any dose change so they can individualize it 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 1.5 mg/day together with erythromycin (a moderate CYP3A4 inhibitor) 500 mg twice daily over 21 days led to an increase in cariprazine AUC (0 to 24 hours) and Cmax of about 50% 1.
Common questions
Can I take Amprenavir and Cariprazine together?
Amprenavir can raise cariprazine levels by blocking its breakdown, so your care team will lower the cariprazine dose while you take both and adjust it back if amprenavir stops. Watch for extra side effects and check with your prescriber before changing anything. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amprenavir 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 Amprenavir and Cariprazine interaction managed?
Keep taking both medications as prescribed. The key here is that your cariprazine dose is tailored while you are on amprenavir. Your care team will typically use a lower cariprazine dose (often as little as 1.5 mg every other day, depending on your current dose and condition) while amprenavir is on board. If amprenavir is later stopped, your cariprazine dose may be increased back up based on how y… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Amprenavir 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
Keep reading about Amprenavir
Keep reading about Cariprazine
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