Belumosudil and Lomitapide: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 15, 2026 · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Lomitapide
No brand names on recordBelumosudil
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. Lomitapide is a cholesterol-lowering medicine that your body breaks down using a liver enzyme called CYP3A4. Belumosudil (Rezurock) slows that enzyme down a little. When the enzyme is slowed, lomitapide isn't cleared as fast, so more of it builds up in your blood.
More lomitapide can mean stronger side effects, like stomach upset, diarrhea, or stress on your liver. The good news is this is very manageable. Your care team simply keeps your lomitapide dose lower and watches your cholesterol response and how you feel. Please don't change anything on your own, just check in with your pharmacist or doctor so they can tailor the dose for you.
Mechanism: Belumosudil is a weak CYP3A4 inhibitor; lomitapide is a sensitive CYP3A4 substrate (not a prodrug). Inhibition reduces lomitapide metabolism, increasing its exposure (AUC/Cmax) and the risk of GI toxicity and hepatotoxicity (transaminase elevations, hepatic steatosis).
Direction/severity: Increased lomitapide effect; major, probable evidence.
Management (per labeling with a weak CYP3A4 inhibitor):
- Cap max lomitapide dose: 10 mg (age 2 to 10), 20 mg (11 to 17), 30 mg (>=18 yr, or ~2/3 max if the weak inhibitor is an oral contraceptive).
- If adding the inhibitor to stable lomitapide, halve the dose, then titrate cautiously per LDL-C response and tolerability.
- Monitor LFTs and GI tolerability.
What happens
Increased lomitapide exposure
Interaction Deep Dive
Taking lomitapide (which is metabolized by CYP3A4) alongside a weak CYP3A4 inhibitor can raise lomitapide exposure. When a weak CYP3A4 inhibitor is used at the same time, the recommended ceiling for lomitapide is 10 mg for ages 2 to 10 years, 20 mg for ages 11 to 17 years, and 30 mg for those 18 years and older. The titration schedule during concurrent weak CYP3A4 inhibitor use is as follows. For ages 2 to 10 years, dosing advances from 2 mg (weeks 0 to 8) to 5 mg (weeks 9 to 12), then 10 mg (weeks 13 to 16), and 20 mg from week 17 onward; higher doses are not recommended. For ages 11 to 15 years, titration starts at 2 mg (weeks 0 to 4), followed by 5 mg (weeks 5 to 8), 10 mg (weeks 9 to 12), 20 mg (weeks 13 to 16), and 40 mg from week 17 onward; the 60 mg dose is not recommended. For ages 16 to 17 years, dosing begins at 2 mg (weeks 0 to 2), then 5 mg (weeks 3 to 6), 10 mg (weeks 7 to 10), 20 mg (weeks 11 to 14), and 40 mg from week 15 onward; the 60 mg dose is not recommended. For those 18 years and older, the titration follows the same pattern as the 16 to 17 year group, but the 60 mg dose is permitted after week 15. If a weak CYP3A4 inhibitor is started in a patient already on a stable lomitapide dose, the lomitapide dose should be cut in half. After that, careful titration to half the maximum recommended dose may be considered according to LDL-C response and safety/tolerability, except when the only coadministered agent is an oral contraceptive, where the maximum recommended lomitapide dose is roughly two thirds of the maximum recommended dose1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of lomitapide
How to manage this interaction
This combination can be managed safely. Because belumosudil raises lomitapide levels, your care team will keep your lomitapide dose lower than usual and titrate it slowly based on your cholesterol (LDL-C) response and how well you tolerate it.
- Keep taking both as prescribed unless your doctor tells you otherwise.
- If belumosudil is being added while you are already stable on lomitapide, your team may cut the lomitapide dose in half and re-titrate carefully.
- Expect closer monitoring, including liver tests and watching for stomach side effects.
- Tell your pharmacist or prescriber about any new nausea, diarrhea, belly pain, or yellowing of skin/eyes.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Giving atorvastatin (a weak CYP3A4 inhibitor) at 80 mg daily together with a single 20 mg dose of lomitapide raised the AUC of lomitapide 2-fold and the Cmax 2.1-fold relative to lomitapide given by itself 1.
Common questions
Can I take Belumosudil and Lomitapide together?
Belumosudil can raise lomitapide levels by slowing its breakdown, so your care team will use a lower, carefully titrated lomitapide dose and monitor your liver and GI tolerance. Keep taking both as prescribed and check in with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Belumosudil and Lomitapide 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 Belumosudil and Lomitapide interaction managed?
This combination can be managed safely. Because belumosudil raises lomitapide levels, your care team will keep your lomitapide dose lower than usual and titrate it slowly based on your cholesterol (LDL-C) response and how well you tolerate it. Keep taking both as prescribed unless your doctor tells you otherwise. If belumosudil is being added while you are already stable on lomitapide, your team m… 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 Belumosudil or Lomitapide 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: JUXTAPID® oral capsules, lomitapide oral capsules. Chiesi USA, Inc. (per Manufacturer), Cary, NC, 2026. DailyMed
Keep reading about Lomitapide
Keep reading about Belumosudil
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist