Macitentan
Macitentan is an endothelin receptor antagonist tablet used to treat pulmonary arterial hypertension (PAH) in adults, reducing the risk of disease progression and hospitalization.
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 14 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Macitentan (Opsumit) is a widely used, once-daily specialist medicine for pulmonary arterial hypertension (PAH, high blood pressure in the lung arteries) that blocks endothelin, a signal that narrows and thickens those vessels, to slow the disease and reduce hospitalizations; it has been on the market since about 2013 and is available as a generic. Most people handle it well; the usual complaints are stuffy nose, sore throat, headache and ankle swelling. The boxed warning is for serious birth defects, so anyone who could become pregnant needs a negative pregnancy test first and reliable birth control until a month after stopping. Expect regular liver and blood count tests.
Clinical pearls
- Food makes no difference to absorption, so choose one time each day, with or without a meal, and stick to it.
- Fluconazole, ketoconazole, rifampin, amiodarone and ritonavir sharply shift macitentan levels, so every prescriber should know you take it.
- Men should know it may lower sperm count, worth raising before starting if you hope to father children.
- Weigh yourself regularly, since rapid weight gain or worsening leg swelling can signal fluid buildup that needs a prompt call.
⚠️ FDA Boxed Warning — the FDA’s strongest safety alert ▾
Macitentan tablets must never be taken during pregnancy. Based on animal studies, this medication can cause serious birth defects and fetal death. If you are a woman who could become pregnant, you must have a negative pregnancy test before starting, use effective birth control throughout your treatment, and continue contraception for one month after your last dose. If you become pregnant while taking macitentan, stop the medication as soon as possible and contact your doctor immediately.
Patient information guide A plain-language walkthrough of Macitentan, written from its FDA label.
What Macitentan is used for
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Macitentan tablets (including the brand Opsumit) are approved for one primary use in adults:
- Pulmonary arterial hypertension (PAH, WHO Group I): Both macitentan tablets and Opsumit are indicated to treat PAH in adults, with the goal of reducing the risk of disease progression and PAH-related hospitalization. Clinical evidence was established in patients with mainly moderate-to-severe symptoms, including those with idiopathic or heritable PAH, PAH caused by connective tissue disorders, and PAH caused by congenital heart disease with repaired shunts.
How Macitentan works
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In pulmonary arterial hypertension, a naturally occurring protein called endothelin-1 (ET-1) is overactive in the lung blood vessels. It binds to two receptors — ET-A and ET-B — and triggers narrowing of the vessels, thickening of vessel walls, and inflammation, all of which raise pressure in the lungs and make the heart work harder. Macitentan is an endothelin receptor antagonist (ERA): it blocks both ET-A and ET-B receptors with high affinity, preventing ET-1 from exerting these harmful effects and helping the lung blood vessels relax and stay open.
Macitentan is broken down in the body into an active metabolite that also blocks ET receptors, though it is less potent than the parent drug. At steady state, this metabolite is present at higher levels than macitentan itself and contributes meaningfully to the overall effect.
Macitentan dosage
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Macitentan tablets are taken once daily by mouth. They can be taken with or without food — studies showed that even a high-fat meal does not change how much of the drug gets into the bloodstream. Follow your prescriber's instructions carefully; do not take more than prescribed, as higher doses have not been studied in PAH patients and are not recommended.
- Take your tablet at the same time each day to stay consistent.
- If you miss a dose, follow your prescriber's guidance — do not double up without checking.
- Women who can become pregnant must complete a pregnancy test before the first dose.
Dosing details from the FDA-approved label
From the Macitentan prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Pulmonary arterial hypertension (PAH)
- 10 mg once daily for oral administration
- Maximum: Doses higher than 10 mg once daily have not been studied in patients with PAH and are not recommended
- Females of reproductive potential
- Exclude pregnancy before initiating treatment
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION • 10 mg once daily. Doses higher than 10 mg once daily have not been studied in patients with PAH and are not recommended ( 2.1 ). 2.1 Recommended Dosage The recommended dosage of macitentan tablets is 10 mg once daily for oral administration. Doses higher than 10 mg once daily have not been studied in patients with PAH and are not recommended. 2.2 Pregnancy Testing in Females of Reproductive Potential Exclude pregnancy before initiating treatment with macitentan tablets in females of reproductive potential [see Boxed Warning , Contraindications (4.1) , Warnings and Precautions (5.1) , and Use in Specific Populations (8.3) ] .
Read the full Dosage and Administration section on DailyMed →
Macitentan side effects
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The most common side effects reported in the main clinical trial (occurring more often than with placebo) include:
Common side effects
- Anemia (low red blood cell count)
- Nasopharyngitis or pharyngitis (runny nose, sore throat)
- Bronchitis (airway inflammation)
- Headache
- Influenza (flu)
- Urinary tract infection
- Bronchitis — cough, airway inflammation
When to get medical help
- Call your doctor right away if you notice yellowing of the skin or eyes, dark urine, severe stomach pain, or unusual fatigue — these can be signs of liver injury
- Tell your doctor immediately if you develop rapid or significant swelling in your legs or feet, or sudden weight gain — this may signal fluid retention or worsening heart failure
- Seek help if you have signs of a severe allergic reaction: swelling of the face or throat, severe rash, or difficulty breathing
- Contact your doctor if you feel unusually short of breath or notice signs of pulmonary edema (fluid in the lungs), which may point to a rare condition called pulmonary veno-occlusive disease
- Tell your doctor if you are pregnant or think you may be pregnant — stop the medication and contact your provider immediately
- Report any symptoms of low blood pressure such as dizziness or fainting
Macitentan warnings and precautions
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- Pregnancy (boxed warning): Macitentan can cause serious birth defects and fetal death. It is absolutely contraindicated in pregnancy. Women who can become pregnant must use effective contraception before, during, and for one month after treatment, and must have a negative pregnancy test before starting.
- Liver injury: This drug class is associated with elevated liver enzymes and, rarely, serious liver damage or failure. Baseline liver testing is required before starting, and repeat testing is done during treatment. Report symptoms of liver problems immediately.
- Fluid retention: Swelling and fluid buildup can occur, sometimes requiring diuretics or hospitalization. Patients with left heart problems are at higher risk.
- Anemia: A meaningful drop in hemoglobin has been seen. Treatment should not be started in patients with severe anemia. Hemoglobin should be checked before and during treatment.
- Pulmonary veno-occlusive disease (PVOD): If signs of pulmonary edema (fluid in the lungs) appear, this rare condition should be considered and the drug discontinued if confirmed.
- Male fertility: Like other drugs in its class, macitentan may reduce sperm count. Men should discuss fertility concerns with their doctor.
Macitentan interactions
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Macitentan is broken down by liver enzymes (mainly CYP3A4, with some involvement of CYP2C8, CYP2C9, and CYP2C19), so drugs that strongly affect these enzymes can significantly change macitentan levels in your blood:
- Rifampin (a strong CYP3A4 inducer): Greatly lowers macitentan levels — avoid combining.
- Ketoconazole, ritonavir, and other strong CYP3A4 inhibitors: Can roughly double macitentan exposure — avoid combining. If you need an HIV medication that is a strong CYP3A4 inhibitor, talk to your doctor about alternative PAH treatments.
- Fluconazole, amiodarone (moderate dual CYP3A4 and CYP2C9 inhibitors): Predicted to increase macitentan exposure about 4-fold — avoid combining.
- Combined moderate CYP3A4 and CYP2C9 inhibitors used together: Also to be avoided alongside macitentan.
- Warfarin: Macitentan does not meaningfully affect warfarin levels or INR — no significant interaction expected.
- Sildenafil: A small increase in sildenafil exposure was seen, but it is not considered clinically significant.
Interactions listed in the FDA-approved label
From the Macitentan prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- Strong CYP3A4 inducers (e.g., rifampin): Significantly reduce macitentan exposure. Avoid concomitant use with macitentan.
- Strong CYP3A4 inhibitors (e.g., ketoconazole, ritonavir): Ketoconazole approximately doubles macitentan exposure; many HIV drugs like ritonavir are strong CYP3A4 inhibitors. Avoid concomitant use; use other PAH treatment options when strong CYP3A4 inhibitors are needed as part of HIV treatment.
- Moderate dual inhibitors of CYP3A4 and CYP2C9 (e.g., fluconazole, amiodarone): Predicted to increase macitentan exposure approximately 4-fold based on PBPK modeling. Avoid concomitant use.
- Combined moderate CYP3A4 inhibitor and moderate CYP2C9 inhibitor: May increase exposure to macitentan. Avoid concomitant treatment with both.
- Warfarin: Macitentan once daily dosing did not alter the exposure to R- and S-warfarin or their effect on INR.
- Sildenafil: Exposure to sildenafil 20 mg t.i.d. increased by 15% with macitentan 10 mg once daily; not considered clinically relevant.
- Hormonal contraceptives (norethisterone 1 mg and ethinyl estradiol 35 µg): Macitentan 10 mg once daily did not affect the pharmacokinetics of the oral contraceptive.
- BCRP substrate drugs (riociguat 1 mg and rosuvastatin 10 mg): Macitentan 10 mg once daily did not affect their pharmacokinetics.
Read the label’s full interactions text
7 DRUG INTERACTIONS • Strong CYP3A4 inducers (rifampin) reduce exposure to macitentan: avoid co-administration with macitentan ( 7.1 , 12.3 ). • Strong CYP3A4 inhibitors (ketoconazole, ritonavir) increase exposure to macitentan: avoid co-administration with macitentan ( 7.2 , 12.3 ). • Moderate dual CYP3A4 and CYP2C9 inhibitors (fluconazole, amiodarone) or use of combined CYP3A4 and CYP2C9 inhibitors may increase exposure to macitentan: avoid co-administration with macitentan ( 7.3 , 12.3 ). 7.1 Strong CYP3A4 Inducers Strong inducers of CYP3A4 such as rifampin significantly reduce macitentan exposure. Concomitant use of macitentan with strong CYP3A4 inducers should be avoided [see Clinical Pharmacology (12.3) ] . 7.2 Strong CYP3A4 Inhibitors Concomitant use of strong CYP3A4 inhibitors like ketoconazole approximately double macitentan exposure. Many HIV drugs like ritonavir are strong inhibitors of CYP3A4. Avoid concomitant use of macitentan with strong CYP3A4 inhibitors [see Clinical Pharmacology (12.3) ] . Use other PAH treatment options when strong CYP3A4 inhibitors are needed as part of HIV treatment [see Clinical Pharmacology (12.3) ] . 7.3 Moderate Dual or Combined CYP3A4 and CYP2C9 Inhibitors Concomitant use of moderate dual inhibitors of CYP3A4 and CYP2C9 such as fluconazole is predicted to increase macitentan exposure approximately 4-fold based on physiologically based pharmacokinetic (PBPK) modeling. Avoid concomitant use of macitentan with moderate dual inhibitors of CYP3A4 and CYP2C9 (such as fluconazole and amiodarone) [see Clinical Pharmacology (12.3) ] . Concomitant treatment of both a moderate CYP3A4 inhibitor and moderate CYP2C9 inhibitor with macitentan should also be avoided [see Clinical Pharmacology (12.3) ].
Drug Interactions In Vitro Studies At plasma levels obtained with dosing at 10 mg once daily, macitentan has no relevant inhibitory or inducing effects on CYP enzymes.
Excerpted — the section continues on the label. Read the full Drug Interactions section on DailyMed →
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Macitentan
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- Pregnancy: Macitentan is contraindicated during pregnancy — it causes birth defects and fetal death in animal studies. A pregnancy test is required before starting.
- Women who can become pregnant: Must use effective contraception before, during, and for one month after stopping treatment.
- Breastfeeding: Do not breastfeed while taking macitentan — potential harm to the infant cannot be ruled out.
- Men: Macitentan may impair sperm production and fertility; discuss concerns with your doctor before starting.
- Severe anemia: Starting treatment is not recommended if you already have severe anemia.
- Liver disease: Tell your doctor about any history of liver problems; liver enzyme monitoring is required.
- Severe kidney disease: Exposure to macitentan and its active metabolite is modestly increased, but this is not considered clinically significant; no dose adjustment is specified in the label.
- Children: Safety and effectiveness have not been established in pediatric patients — a study conducted in children did not demonstrate clinical benefit.
- Older adults (65+): No overall differences in safety or effectiveness were observed compared to younger adults in the clinical study.
- Hypersensitivity: Do not take if you have had a prior allergic reaction to macitentan or any ingredient in the tablet.
Macitentan overdose
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In studies in healthy volunteers, single doses far above the recommended amount caused headache, nausea, and vomiting. If an overdose is suspected, standard supportive care should be provided. Dialysis is unlikely to help remove macitentan from the body because it is very tightly bound to proteins in the blood — contact Poison Control or go to an emergency room right away.
What Macitentan does in the body
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In a subset of PAH patients treated for 6 months, macitentan produced a median 37% reduction in pulmonary vascular resistance (the resistance the right heart pumps against) compared to placebo, and meaningfully increased cardiac index (the amount of blood the heart pumps per minute relative to body size). These changes reflect real improvements in how blood flows through the lungs. In separate cardiac safety testing, macitentan had no significant effect on the QTc interval (a measure of heart rhythm), even at doses three times the approved amount.
How your body processes Macitentan
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After a single oral dose, macitentan reaches peak blood levels in about 8 hours. It can be taken with or without food — a high-fat meal does not affect absorption. Macitentan is broken down mainly by the liver enzyme CYP3A4 into an active metabolite, which stays in the body longer (half-life of about 48 hours versus about 16 hours for macitentan itself) and at higher concentrations at steady state. Both macitentan and its metabolite are more than 99% protein-bound. The drug is eliminated primarily in urine (about 50%) and feces (about 24%), though neither macitentan nor its active metabolite are excreted unchanged. Age, sex, and race do not have clinically meaningful effects on drug levels.
How to store Macitentan
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Store at 20 ºC to 25 ºC (68 ºF to 77 ºF). Keep out of reach of children.
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Macitentan
253 supplements and herbal products have documented interactions with Macitentan in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 9
- Moderate · 205
- Minor · 39
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Nutrient depletion considerations
Macitentan has been associated with lower levels of 1 nutrient in the clinical literature. This does not mean a deficiency will occur — it means these may be worth discussing with your pharmacist or healthcare provider, especially with long-term use.
Educational information from a licensed clinical database (Natural Medicines) — not medical advice. Do not start or stop medications or supplements without professional guidance.
Macitentan: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Macitentan — the kind of thing our pharmacy team would talk through with you at the counter.
What exactly does macitentan do, and why do I need to take it every day?
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Can I take this pill with food, or do I need to take it on an empty stomach?
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I'm a woman who might want to have children someday. What do I need to know about this medication and pregnancy?
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What side effects should I just watch for, versus which ones mean I should call my doctor right away?
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Are there any medications I need to avoid while I'm on macitentan?
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I'm a man — is there anything specific I should know about this drug affecting me?
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Is Macitentan available over the counter?
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When was Macitentan first available?
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Who makes Macitentan?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Macitentan on HelloPharmacist
Macitentan forms and strengths (how it comes)
Macitentan is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Macitentan inactive ingredients by manufacturer.
Tablet
How this form is used
- Macitentan tablets are indicated to treat pulmonary arterial hypertension (PAH, WHO Group I) in adults to reduce the risks of disease progression and hospitalization
- Opsumit (brand film-coated tablet) is indicated for the same PAH indication in adults
- Macitentan tablets are taken by mouth once daily
- Macitentan tablets may be taken with or without food
- Opsumit tablets are taken by mouth once daily
- Opsumit tablets may be taken with or without food — a high-fat meal does not meaningfully affect absorption
Macitentan on the U.S. market: products, makers and brands
How Macitentan appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
14 companies list 14 Macitentan product records with the FDA, mostly as tablet; the earliest marketing or approval year on record is 2013. Brand names on the directory include Opsumit; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (11) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
How widely Macitentan is used (Medicaid data)
A general measure of how commonly Macitentan is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Macitentan is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Macitentan prescribed? Of the 1,601 medications we measure, Macitentan ranks #814 by Medicaid prescriptions — more than 49% of them.
Utilization by Macitentan product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
macitentan 10 MG Oral Tablet
Summed across the 1 of 25 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 1442137
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Macitentan, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 1 of 25 listed Macitentan NDCs with Medicaid activity.
Compare Macitentan products
A representative set of FDA-listed product records for Macitentan — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Tablet | ||||
| 10 mg | Oral | Actelion Pharmaceuticals US, Inc. | NDA | View NDC → |
| 10 mg | Oral | Alembic Pharmaceuticals Inc. | ANDA | View NDC → |
| 10 mg | Oral | Alembic Pharmaceuticals Limited | ANDA | View NDC → |
| 10 mg | Oral | Amneal Pharmaceuticals NY LLC | ANDA | View NDC → |
| 10 mg | Oral | Apotex Corp. | ANDA | View NDC → |
| 10 mg | Oral | Aurobindo Pharma Limited | ANDA | View NDC → |
| 10 mg | Oral | Laurus Labs Limited | ANDA | View NDC → |
| 10 mg | Oral | Mylan Pharmaceuticals Inc. | ANDA | View NDC → |
| 10 mg | Oral | Novugen Pharma (USA) LLC | ANDA | View NDC → |
| 10 mg | Oral | Sandoz Inc | ANDA | View NDC → |
| 10 mg | Oral | Sun Pharmaceutical Industries, Inc. | ANDA | View NDC → |
| 10 mg | Oral | Teva Pharmaceuticals, Inc. | ANDA | View NDC → |
| 10 mg | Oral | Torrent Pharmaceuticals Limited | ANDA | View NDC → |
| 10 mg | Oral | Zydus Pharmaceuticals USA Inc. | ANDA | View NDC → |
Showing 14 of 14 products — FDA National Drug Code Directory. See every product, package size and price: browse all 14 Macitentan NDCs →
Macitentan side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Macitentan — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Macitentan in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Macitentan FDA approval history
How Macitentan went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Macitentan recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Macitentan recalls since July 2021.
✅No Macitentan recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 1442132 1 dose form · 1 strength
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Dose form (SCDF) Oral Tablet RxCUI 1442136In current FDA listingsClinical drug / strength (SCD) 10 MGRxCUI 1442137
Look up RxCUI 1442132 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Macitentan supply and shortage status
Whether Macitentan is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
Macitentan brand names
Macitentan is sold under one brand name in the FDA directory — Opsumit. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Macitentan: manufacturers and labelers
14 companies list Macitentan products with the FDA. By number of product records, the largest are Actelion Pharmaceuticals US, Inc., Alembic Pharmaceuticals Inc., Alembic Pharmaceuticals Limited. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Macitentan drug class (RxNorm)
Macitentan belongs to the Endothelin Receptor Antagonist class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Macitentan page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Actelion Pharmaceuticals US, Inc. is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →