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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Orenitram
Generic Name
Treprostinil
Active Ingredient
TreprostinilCategory
Prostacycline Vasodilator [EPC]
Variants
8
References used for this content
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Orenitram, you must consult a qualified healthcare professional.
| .125 mg/1 | TABLET, EXTENDED RELEASE | ORAL | 66302-300 |
| 5 mg/1 | TABLET, EXTENDED RELEASE | ORAL | 66302-350 |
| .25 mg/1 | TABLET, EXTENDED RELEASE | ORAL | 66302-302 |
| 1 mg/1 | TABLET, EXTENDED RELEASE | ORAL | 66302-310 |
| KIT | — | 66302-361 |
Detailed information about Orenitram
Treprostinil is a potent prostacyclin vasodilator used to treat pulmonary arterial hypertension (PAH) by dilating blood vessels in the lungs and improving exercise capacity.
Dosage for Treprostinil is highly individualized and requires careful titration by a specialist in pulmonary hypertension.
For patients new to prostacyclin therapy, the initial infusion rate is typically 1.25 ng/kg/min. If this initial dose is not tolerated, the rate may be reduced to 0.625 ng/kg/min. Healthcare providers will then increase the dose based on clinical response and tolerability, usually in increments of 1.25 ng/kg/min per week for the first four weeks, and then by 2.5 ng/kg/min per week for the remainder of the treatment. Many patients achieve an optimal maintenance dose between 40 ng/kg/min and 80 ng/kg/min, though some may require higher doses.
The initial dose of inhaled Treprostinil is 3 breaths (18 mcg) per treatment session, administered four times daily during waking hours. Sessions should be spaced approximately 4 hours apart. The dose is typically increased by an additional 3 breaths per session every 1 to 2 weeks, with a target maintenance dose of 9 to 12 breaths (54–72 mcg) four times daily.
The starting dose for patients not currently on a prostacyclin is 0.125 mg three times daily (TID) or 0.25 mg twice daily (BID). Doses are increased by 0.125 mg TID or 0.25–0.5 mg BID every 3 to 4 days. The goal is to reach a dose that maximizes clinical benefit while minimizing side effects such as headache and nausea.
Treprostinil is not currently FDA-approved for use in pediatric patients. While some specialists may use Treprostinil off-label in children with severe PAH, safety and efficacy have not been formally established in clinical trials for patients under the age of 18. Pediatric dosing, when performed, is usually calculated based on body weight and closely follows adult titration protocols under intense medical supervision.
No specific dosage adjustments are required for patients with renal impairment, as Treprostinil is primarily cleared by hepatic metabolism. However, because metabolites are excreted renally, patients with severe renal disease should be monitored closely for unexpected side effects.
Treprostinil is extensively metabolized by the liver. For parenteral use in patients with mild-to-moderate hepatic impairment, the initial dose should be decreased to 0.625 ng/kg/min and increased cautiously. For the oral form (Orenitram), it is contraindicated in patients with severe hepatic impairment (Child-Pugh Class C). In mild hepatic impairment (Child-Pugh Class A), the starting dose is 0.125 mg BID with cautious titration. In moderate impairment (Child-Pugh Class B), the starting dose is 0.125 mg once daily.
Clinical studies did not include sufficient numbers of patients aged 65 and over to determine if they respond differently than younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function.
Subcutaneous infusion is delivered via a small catheter inserted under the skin, usually in the abdomen or thigh. Intravenous infusion requires a central venous catheter. Both require a dedicated infusion pump. Patients must be trained on sterile technique, pump programming, and troubleshooting alarms.
Use only the manufacturer-specified nebulizer or dry powder inhaler. The solution should not come into contact with the eyes or skin. Clean the device daily as instructed to prevent infection and ensure proper dosing.
Orenitram tablets must be swallowed whole. Do not crush, split, or chew them, as this destroys the extended-release mechanism and can lead to a dangerous rapid release of the drug. Take with food to increase absorption and reduce stomach upset.
If a dose of oral Treprostinil is missed, take it as soon as possible with food. If it is almost time for the next dose, skip the missed dose and resume the regular schedule. Do not double the dose. For inhaled Treprostinil, if a session is missed, resume the next session as scheduled. For parenteral infusion, a missed dose is a medical emergency; if the pump stops or the catheter is dislodged, contact your medical team immediately to avoid rebound PAH.
Symptoms of Treprostinil overdose include flushing, headache, hypotension (low blood pressure), nausea, vomiting, and diarrhea. In the event of an overdose, the infusion should be slowed or stopped, and supportive care should be initiated to manage blood pressure and hydration. Seek emergency medical attention immediately if an overdose is suspected.
> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop the medication without direct medical guidance, as sudden changes can lead to a life-threatening worsening of your condition.
Side effects of Treprostinil are largely related to its pharmacological action as a potent vasodilator and are often dose-dependent. The most frequently reported side effects include:
Treprostinil is a high-alert medication that requires specialized management. It should only be prescribed by physicians experienced in the diagnosis and treatment of Pulmonary Arterial Hypertension (PAH). Patients must be committed to the rigorous requirements of the therapy, including the maintenance of infusion pumps or the frequent daily dosing required for inhaled and oral forms. The most critical safety aspect of Treprostinil therapy is the prevention of treatment interruption, particularly for the parenteral (IV/SC) forms.
No FDA black box warnings for Treprostinil. However, the risk of rebound pulmonary hypertension due to abrupt withdrawal is considered a critical safety concern that carries similar weight in clinical practice.
While there are few absolute contraindications for drug combinations, the use of Treprostinil with strong CYP2C8 inhibitors (such as gemfibrozil) requires extreme caution and significant dose reduction. Gemfibrozil can increase the systemic exposure (AUC) of Treprostinil by approximately 2-fold, which significantly increases the risk of severe vasodilatory side effects and toxicity. If co-administration is unavoidable, the healthcare provider must reduce the Treprostinil dose.
Treprostinil must NEVER be used in the following circumstances:
These are conditions where the risk-benefit ratio must be carefully weighed by a specialist:
Treprostinil is classified as Pregnancy Category B (under the old FDA system), meaning animal reproduction studies have failed to demonstrate a risk to the fetus, but there are no adequate and well-controlled studies in pregnant women. In clinical practice, PAH itself carries a very high risk of maternal and fetal mortality (up to 30-50%). Therefore, most specialists recommend continuing PAH therapy during pregnancy under the care of a high-risk obstetrician. Data from the REVEAL registry and other PAH databases suggest that while prostacyclins are used, patients must be monitored for fluid shifts and heart failure during the third trimester and delivery.
It is not known whether Treprostinil is excreted in human milk or what its effects might be on a nursing infant. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Treprostinil, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Safety and effectiveness in pediatric patients have not been established. Clinical use in children is generally limited to specialized centers. Pediatric patients may be more sensitive to the vasodilatory effects, and dosing must be meticulously adjusted for weight. There are no long-term data on the effects of Treprostinil on growth and development in children.
Treprostinil is a tricyclic benzindene analogue of prostacyclin (PGI2). Its primary mechanism of action is the direct activation of the prostacyclin (IP) receptor. Upon binding to the IP receptor on vascular smooth muscle cells, it stimulates the Gs-protein-adenylate cyclase pathway, increasing the production of cyclic adenosine monophosphate (cAMP). Increased cAMP leads to a decrease in intracellular calcium and promotes the relaxation of smooth muscle, resulting in potent vasodilation of the pulmonary and systemic arterial beds. Additionally, Treprostinil binds to IP receptors on platelets, increasing cAMP and inhibiting platelet activation and aggregation.
The hemodynamic effects of Treprostinil include a decrease in pulmonary vascular resistance (PVR), a decrease in mean pulmonary arterial pressure (mPAP), and an increase in cardiac index (CI) and mixed venous oxygen saturation (SvO2). These effects are dose-dependent. Unlike epoprostenol, Treprostinil is chemically stable at neutral pH and room temperature, which allows for a more consistent delivery profile. The onset of effect for IV/SC administration is nearly immediate, while the duration of effect after stopping an infusion is several hours, providing a wider safety margin than epoprostenol.
Common questions about Orenitram
Treprostinil is primarily used to treat Pulmonary Arterial Hypertension (PAH), which is high blood pressure in the arteries of the lungs. It works by dilating these blood vessels, which lowers the pressure and allows the heart to pump blood more efficiently. This leads to a significant improvement in exercise capacity and a reduction in symptoms like shortness of breath and fatigue. It is also used for Chronic Thromboembolic Pulmonary Hypertension (CTEPH) in its inhaled form. Healthcare providers typically prescribe it for patients with WHO Functional Class II, III, or IV symptoms.
The most common side effects depend on how the drug is taken but generally include headache, diarrhea, jaw pain, and nausea. For those using the subcutaneous infusion (Remodulin), infusion site pain and redness are extremely common, affecting the vast majority of patients. Inhaled Treprostinil (Tyvaso) often causes a cough or throat irritation. These side effects are mostly due to the drug's action as a vasodilator and are often most intense when the dose is being increased. Most patients find that these symptoms become more manageable over time as their body adjusts to the medication.
It is generally recommended to limit or avoid alcohol while taking Treprostinil. Alcohol acts as a vasodilator, meaning it widens blood vessels, which is the same thing Treprostinil does. Combining the two can lead to an additive effect, causing a significant drop in blood pressure (hypotension). This can result in severe dizziness, lightheadedness, or even fainting (syncope). If you do choose to drink, it should be in moderation and only after you have reached a stable dose of Treprostinil and know how it affects you.
Treprostinil is generally used during pregnancy only if the potential benefit to the mother outweighs the risk to the fetus. While animal studies haven't shown direct harm, there is limited data in human pregnancies. However, untreated Pulmonary Arterial Hypertension is extremely dangerous for both the mother and the baby. Therefore, most specialists will continue Treprostinil treatment during pregnancy under very close monitoring. If you are pregnant or planning to become pregnant, you must have a detailed discussion with your PAH specialist and a high-risk obstetrician.
The time it takes to feel the benefits of Treprostinil can vary based on the delivery method and the speed of dose titration. For parenteral (IV/SC) infusion, some hemodynamic improvements can be seen within days, but it may take several weeks or months of gradual dose increases to reach the optimal therapeutic effect. For oral and inhaled forms, exercise capacity improvements are typically measured after 12 weeks of consistent use. Because the dose is started very low to minimize side effects, patience is required during the titration phase. Always communicate with your doctor if you do not feel an improvement after several months.
No, you must never stop taking Treprostinil suddenly, especially if you are using the intravenous or subcutaneous forms. Treprostinil has a short half-life, and stopping it abruptly can cause a life-threatening 'rebound' of pulmonary hypertension. This can lead to acute right heart failure, severe shortness of breath, and even death. Patients using pumps must always have a backup pump and extra supplies to ensure there is no interruption in therapy. If you must stop the medication for a medical reason, it must be done under strict hospital supervision with a gradual dose taper.
If you miss a dose of the oral tablets (Orenitram), take it as soon as you remember with food, unless it is almost time for your next dose. For the inhaled form, simply take the next scheduled session. However, for the continuous infusion (IV/SC), a 'missed dose' usually means a pump failure or a disconnected catheter, which is a medical emergency. You should immediately switch to your backup pump or contact your emergency PAH medical team. Never double a dose of the oral or inhaled medication to make up for a missed one.
Weight gain is not a direct side effect of the Treprostinil molecule itself. However, some patients may experience peripheral edema (swelling in the legs and ankles) due to the drug's effect on blood vessels, which can lead to a slight increase in weight due to fluid retention. Conversely, if Treprostinil successfully improves your heart function, it may actually help reduce fluid buildup associated with heart failure. If you notice a sudden or significant increase in weight (e.g., more than 3 pounds in a day), you should contact your doctor, as it may indicate a change in your heart failure status.
Treprostinil can be taken with many other medications, but there are important exceptions. It is often used in combination with other PAH drugs like sildenafil or bosentan. However, it can interact with blood thinners (like warfarin) to increase bleeding risk, and with blood pressure medications to cause excessively low blood pressure. It also interacts with drugs that affect the CYP2C8 liver enzyme, such as gemfibrozil or rifampin. You must provide your healthcare provider with a complete list of all prescriptions, over-the-counter drugs, and supplements you are taking.
Yes, Treprostinil is available as a generic medication for the injectable (parenteral) form, which was previously only available as the brand Remodulin. Generic versions of the inhaled solution have also become available. However, the oral extended-release form (Orenitram) and the dry powder inhaler (Tyvaso DPI) may still be under patent protection in various regions. Generic versions are required by the FDA to be bioequivalent to the brand-name drug, meaning they work the same way in the body. Consult your pharmacist or insurance provider to see if a generic version is available for your specific prescription.
Other drugs with the same active ingredient (Treprostinil)
> Warning: Stop taking Treprostinil (or contact your emergency PAH team) and call your doctor immediately if you experience any of these.
With prolonged use, some patients may develop a tolerance to the vasodilatory effects, requiring gradual dose increases over years. There is also the risk of chronic skin changes at subcutaneous infusion sites, such as scarring or lipodystrophy. Long-term use of IV Treprostinil carries the cumulative risk of multiple catheter-related complications, including venous thrombosis (clots in the veins) and the need for repeated surgical catheter placements.
There are currently no FDA Black Box Warnings for Treprostinil. However, the manufacturer and the FDA emphasize a Major Warning regarding the risk of abrupt discontinuation. Unlike many other medications, prostacyclins like Treprostinil have a very short half-life. If the delivery is interrupted for even a few hours, the patient may experience a 'rebound' effect where the pulmonary arteries constrict violently, potentially leading to a medical emergency or death. Patients must always have a backup pump, extra batteries, and a backup supply of medication available at all times.
Report any unusual symptoms or side effects to your healthcare provider immediately. Managing side effects often involves slow titration rather than stopping the drug entirely.
Patients on Treprostinil require frequent medical follow-up, especially during the first few months of therapy. Monitoring typically includes:
Treprostinil may cause dizziness, lightheadedness, or fainting due to its effects on blood pressure. Patients should not drive or operate heavy machinery until they know how the medication affects them, particularly during the dose titration phase.
Alcohol can also act as a vasodilator and may enhance the blood-pressure-lowering effects of Treprostinil, increasing the risk of fainting or severe dizziness. It is generally advised to limit alcohol consumption while on this therapy.
If Treprostinil must be discontinued, it should be done gradually under the direct supervision of a PAH specialist. Tapering the dose slowly allows the body to adjust and minimizes the risk of rebound symptoms. Sudden cessation is only considered in life-threatening situations such as severe sepsis where the catheter must be removed immediately, and even then, alternative PAH therapies are usually started simultaneously.
> Important: Discuss all your medical conditions, including any history of liver disease, bleeding disorders, or low blood pressure, with your healthcare provider before starting Treprostinil.
Treprostinil is not known to significantly interfere with most common laboratory tests. However, because it inhibits platelet aggregation, specialized platelet function tests (like aggregometry) will show abnormal results, which is a reflection of the drug's pharmacological activity rather than a 'test interference.'
For each major interaction, the management strategy usually involves:
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. Even over-the-counter medications like aspirin can significantly change how Treprostinil works in your body.
There is no documented cross-sensitivity between Treprostinil and other prostacyclin analogues like epoprostenol or iloprost. However, if a patient has had a severe systemic allergic reaction to one prostacyclin, healthcare providers will typically monitor the first dose of a different prostacyclin very closely in a clinical setting.
> Important: Your healthcare provider will evaluate your complete medical history, including liver function and bleeding risks, before prescribing Treprostinil. Always disclose any previous allergic reactions to medications.
Clinical studies of Treprostinil did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Elderly patients generally have a higher incidence of hepatic and renal dysfunction, as well as concurrent medications. Therefore, dose titration in the elderly should be even more gradual than in younger adults. There is an increased risk of falls in the elderly if hypotension occurs during titration.
No dose adjustments are generally required for patients with renal impairment or those on dialysis, as the drug is primarily cleared by the liver. However, the primary metabolites are excreted in the urine, and their accumulation in severe renal failure has not been fully studied. Patients with a GFR < 30 mL/min should be monitored closely for increased side effects.
> Important: Special populations require individualized medical assessment. Always inform your specialist if you are planning a pregnancy or have underlying organ dysfunction.
| Parameter | Value |
|---|---|
| Bioavailability | ~100% (SC), ~17% (Oral) |
| Protein Binding | ~91% |
| Half-life | ~4.4 hours (Parenteral), ~4 hours (Oral) |
| Tmax | Immediate (IV), 20 min (SC), 4-6 hours (Oral) |
| Metabolism | Hepatic (Primary CYP2C8, Secondary CYP2C9) |
| Excretion | Renal 79%, Fecal 13% |
Treprostinil is classified as a Prostacyclin Vasodilator. It is part of the 'Prostacyclin Pathway' of PAH treatments, which also includes epoprostenol (Flolan, Veletri), iloprost (Ventavis), and the non-prostanoid IP receptor agonist selexipag (Uptravi). Within this class, Treprostinil is unique for its versatility in administration routes (IV, SC, Inhaled, and Oral).