Orenitram (Treprostinil) - Oral

What Is Orenitram?

Orenitram (treprostinil) is a prescription medication used to treat pulmonary arterial hypertension (PAH) in adults.

Orenitram is a tricyclic analog of prostacyclin, a hormone that is produced in blood vessels. As a vasodilator, it works by directly widening the blood vessels (vasodilation) of the lungs and other parts of the body to improve blood flow. It also stops platelets from clumping together in the blood (platelet aggregation), and it hinders the growth and division of smooth muscle cells (smooth muscle proliferation). All of these mechanisms of action help delay disease progression and improve exercise capacity for people with PAH.

Orenitram is available in extended-release form as a tablet. Treprostinil is also available in inhaled and intravenous forms; however, this article focuses on the oral version.

Drug Facts

Generic Name: Treprostinil

Brand Name(s): Orenitram

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Vasodilator

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Treprostinil

Dosage Form(s): Extended-release tablet

What Is Orenitram Used For?

Orenitram is used to treat pulmonary arterial hypertension (PAH) in adults.

PAH is a form of pulmonary hypertension (blood pressure in the lungs). It occurs when the small arteries in the lungs thicken and narrow, blocking blood flow. This, in turn, causes the heart to work harder to pump blood to the rest of the body.

Orenitram helps widen blood vessels, and it inhibits platelet aggregation and smooth muscle cell proliferation, thereby improving blood flow and lessening the workload for your heart.

How to Take Orenitram

Take Orenitram with food as prescribed by your healthcare provider. Swallow the tablets whole; do not crush, split, or chew them.

When starting Orenitram, your healthcare provider may frequently change your dose to find out which works best for you. Part of the tablet may pass into your stool. Do not be alarmed if this happens; this is normal.


Store Orenitram in a closed container at room temperature (68 F to 77 F), away from heat, moisture, and direct light. Do not keep the tablets in the bathroom.

What Are the Side Effects of Orenitram?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

The most common side effects associated with Orenitram include:

  • Headache
  • Nausea and vomiting
  • Diarrhea
  • Flushing of the skin
  • Jaw pain

Severe Side Effects

Call your healthcare provider immediately if you have serious side effects. Call 911 if your symptoms feel life-threatening or if you think you’re having a medical emergency. Serious side effects and their symptoms can include the following:

  • Allergic reaction: Symptoms may include itching or hives, swelling of the face, swelling or tingling in your mouth or throat, chest tightness, or trouble breathing.
  • Worsening PAH symptoms: Suddenly stopping Orenitram can cause your PAH symptoms to worsen. Do not stop this medication without talking to your healthcare provider.

Report Side Effects

Orenitram may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your provider may send a report to the FDA's MedWatch Adverse Event Reporting Program online or by phone (800-332-1088).

Dosage: How Much Orenitram Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (extended-release tablets):
    • For pulmonary arterial hypertension:
      • Adults—At first, 0.25 milligrams (mg) two times a day with food, taken 12 hours apart, or 0.125 mg three times a day, taken 8 hours apart. Your doctor may increase your dose as needed and tolerated.
      • Children—Use and dose must be determined by your doctor.


There is not enough evidence to determine whether taking Orenitram during pregnancy poses any risks to the fetus. However, PAH itself has been shown to carry potential risks to the pregnant patient and the fetus. Talk to your healthcare provider if you are pregnant or breastfeeding.

Certain factors may affect how you take this medication, potentially requiring a dosage adjustment. Talk to your healthcare provider if any of the following circumstances apply to you:

  • Intolerable reactions to the dosing increments
  • Mild liver impairment
  • Taking a strong cytochrome P4502C8 (CYP2C8) inhibitor, such as the cholesterol medication Lopid (gemfibrozil). Talk to your healthcare provider if you are unsure whether you are taking a CYP2C8 inhibitor.

Moreover, your healthcare provider will modify your dose if you transition from an intravenous or subcutaneous administration route to the oral version of treprostinil.

Missed Dose

If you miss your dose of Orenitram, take it as soon as you remember. If it is almost time for your next dose, wait until then and take your regular dose. Do not take extra to make up for a missed dose. If you miss two or more doses, call your healthcare provider, as you may need a dose adjustment.

Overdose: What Happens If I Take Too Much Orenitram?

Signs of an overdose with Orenitram include:

Overdose symptoms are usually treated supportively, but seek medical attention if these symptoms become severe.

What Happens If I Overdose on Orenitram?

If you think you or someone else may have overdosed on Orenitram, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Orenitram, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits to make sure this medicine is working properly and to check for unwanted effects. Blood tests may be needed to check for unwanted effects.

You should not use other medicines that also contain treprostinil. This includes Remodulin® or Tyvaso®. Using these medicines together may increase your chance for more serious side effects.

Do not suddenly stop using this medicine. Stopping or changing the dose of this medicine suddenly may bring on symptoms of your condition and can be dangerous. Check with your doctor before stopping or changing your dose.

This medicine may increase risk of bleeding, especially in patients receiving blood thinners. Tell your doctor if you are taking a blood thinner (such as warfarin).

While taking the medicine, part of the tablet may pass into your stools. This is usually normal. But, if you have diverticulosis (bowel problem), the tablet shell may get stuck in a blind pouch or diverticulum in your intestine.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Orenitram?

Do not take Orenitram if you have advanced liver disease. Orenitram is metabolized in the liver; therefore, drug clearance is significantly affected by the degree of liver impairment.

What Other Medications Interact With Orenitram?

Orentram can interact with the following medications:

  • Lopid (gemfibrozil), a CYP2C8 inhibitor, can increase your exposure to treprostinil if taken simultaneously with Orenitram. Your healthcare provider may need to lower your dose to avoid unwanted side effects.
  • Other medications containing treprostinil, such as Remodulin and Tyvaso
  • Blood pressure-lowering drugs, diuretics, or other vasodilators: Using these medications with treprostinil can increase the risk of hypotension.
  • Anticoagulants (e.g., warfarin, brand names Coumadin, Jantoven): Anticoagulant use with treprostinil may increase the risk of bleeding.

Talk to your healthcare provider if you use any of the above-listed medications. This is not an all-inclusive list of drugs that can interact with Orenitram. Ask your healthcare provider or pharmacist before using any other drugs or herbal products with Orenitram.

What Medications Are Similar?

Orenitram is a derivative of epoprostenol; therefore, the medication epoprostenol (e.g., Flolan, Veletri) is similar to Orenitram. Epoprostenol also treats pulmonary hypertension.

Additionally, other vasodilators used to treat PAH include:

  • Remodulin (treprostinil), which has the same active ingredient as Orenitram but comes in a subcutaneous formulation administered by infusion
  • Ventavis (iloprost)
  • Tyvaso (treprostinil, which has the same active ingredient as Orenitram but is administered via inhalation)
  • Letairis (ambrisentan)
  • Revatio (sildenafil)
  • Adcirca (tadalafil)

Frequently Asked Questions

  • What is Orenitram used for?

    Orenitram is a prescription medication used to treat pulmonary arterial hypertension.

  • What are the mechanisms of action of Orenitram?

    Orenitram belongs to a class of medications known as vasodilators. It causes direct vasodilation (widening) of the pulmonary and systemic arterial blood vessels. Additionally, it stops platelets from clumping together in the blood and blocks the growth and division of smooth muscle cells.

  • How do I stop taking Orenitram?

    Do not abruptly stop taking Orenitram. Your healthcare provider will need to slowly decrease (taper) your dose before you can stop taking Orenitram completely.

How Can I Stay Healthy While Taking Orenitram?

PAH is a serious health condition; however, Orenitram and other treatments can help manage the condition and prevent it from progressing. Make sure to take your medication as prescribed; do not stop taking it abruptly, as this can worsen your symptoms.

In addition to pharmacologic treatment, lifestyle changes can play a role in maintaining your overall health with PAH. Instilling the following habits in your day-to-day life may be useful in staying healthy:

  • Quitting or staying away from smoking
  • Staying active and exercising. Talk to your healthcare team about creating a safe yet effective exercise plan.
  • Sticking to a well-balanced, nutritious diet; avoiding unhealthy fats; and limiting salt intake

Additionally, Orenitram can increase your risk of bleeding. Report any signs or symptoms of bleeding to your healthcare provider.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Orenitram label.

  2. Kumar P, Thudium E, Laliberte K, Zaccardelli D, Nelsen A. A comprehensive review of treprostinil pharmacokinetics via four routes of administration. Clin Pharmacokinet. 2016;55(12):1495-1505. doi:10.1007/s40262-016-0409-0

  3. American Lung Association. Learn about pulmonary arterial hypertension.

  4. Orenitram. Orenitram patient information.

  5. Pugliese SC, Bull TM. Clinical use of extended-release oral treprostinil in the treatment of pulmonary arterial hypertension. Integr Blood Press Control. 2016;9:1-7. doi:10.2147/IBPC.S68230

  6. Kumar P, Thudium E, Laliberte K, Zaccardelli D, Nelsen A. A comprehensive review of treprostinil pharmacokinetics via four routes of administration. Clin Pharmacokinet. 2016;55(12):1495-1505. doi:10.1007/s40262-016-0409-0

  7. MedlinePlus. Epoprostenol.

  8. American Lung Association. Treating and managing pulmonary arterial hypertension.