TREPROSTINIL
Clinical safety rating: safe
Animal studies have demonstrated safety
Treprostinil is a synthetic prostacyclin analogue that directly vasodilates pulmonary and systemic arterial beds, inhibits platelet aggregation, and suppresses vascular smooth muscle proliferation via activation of IP receptors and subsequent increase in cAMP levels.
| Metabolism | Primarily hepatic metabolism via CYP2C8 and CYP2C9 isoenzymes; also undergoes glucuronidation. |
| Excretion | Primarily hepatic metabolism via CYP2C8; renal excretion of unchanged drug is approximately 4% of the dose. |
| Half-life | Terminal half-life is approximately 4 hours for intravenous administration; clinical context: requires continuous infusion due to short half-life. |
| Protein binding | 91% bound to human plasma proteins, primarily albumin. |
| Volume of Distribution | Approximately 0.28 L/kg, indicating distribution mainly in extracellular fluid. |
| Bioavailability | Subcutaneous: approximately 100%; oral: approximately 17% (under fasting conditions) due to first-pass metabolism. |
| Onset of Action | Intravenous: within minutes; subcutaneous: onset within 30 minutes; oral: approximately 1-2 hours. |
| Duration of Action | Intravenous: duration is dependent on infusion rate; subcutaneous: duration approximately 3-4 hours per injection; oral: duration approximately 4-6 hours. |
| Molecular Weight | 390.52 |
Continuous subcutaneous or intravenous infusion via infusion pump. Initial rate: 1.25 ng/kg/min; if not tolerated, reduce to 0.625 ng/kg/min. Titrate in increments of 1.25 ng/kg/min per week for first 4 weeks, then 2.5 ng/kg/min per week as tolerated. Typical maintenance dose: 25-40 ng/kg/min. Duration: continuous long-term.
| Dosage form | INJECTABLE |
| Renal impairment | No specific dose adjustment required for renal impairment. Pharmacokinetics unaffected by GFR. Caution in severe renal impairment due to limited data. |
| Liver impairment | Child-Pugh Class A: reduce initial dose to 0.625 ng/kg/min and titrate slowly. Child-Pugh Class B: initial dose 0.625 ng/kg/min with cautious titration. Child-Pugh Class C: contraindicated or avoid due to lack of data. |
| Pediatric use | Safety and efficacy not established in pediatric patients. Limited data: initial dose 1.25 ng/kg/min by continuous infusion, titrate similarly to adults but with careful monitoring. |
| Geriatric use | No specific dose adjustment required based on age alone. Use same dosing as adults; monitor renal and hepatic function as they decline with age. |
| 1st trimester | Limited human data; animal studies show fetal harm. Use only if benefit outweighs risk. |
| 2nd trimester | May cause fetal harm; consider maternal benefit vs risk. |
| 3rd trimester | May cause fetal harm; consider maternal benefit vs risk. |
Clinical note
Other vasodilators or antihypertensive drugs can have additive effects Can cause infusion site pain and reaction.
| Placental transfer | Expected to cross placenta due to low molecular weight; animal studies confirm transfer. |
| Breastfeeding | No human data; likely present in milk due to low molecular weight. Use with caution, monitor infant for adverse effects. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA boxed warning exists for treprostinil.
| Common Effects | Headache |
| Serious Effects |
Hypersensitivity to treprostinil or any excipient
| Precautions | Sudden dose reductions or interruptions may cause rebound pulmonary hypertension; monitor for bleeding risk due to antiplatelet effects; use caution in patients with hepatic or renal impairment; may cause hypotension; infusion site reactions with subcutaneous route. |
| Food/Dietary | Avoid high-fat meals as they may decrease drug absorption; maintain consistent dietary habits. Grapefruit and grapefruit juice may increase serum levels—consult doctor before consuming. |
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| L4 |
| Teratogenic Risk | Pregnancy Category B. In animal studies, treprostinil administered during organogenesis at doses up to 6 times the human exposure (based on AUC) did not cause fetal harm. However, there are no adequate and well-controlled studies in pregnant women. Treprostinil should be used during pregnancy only if clearly needed. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and signs of bleeding or bruising. Fetal monitoring should include growth and well-being assessments via ultrasound and non-stress testing, especially in the third trimester. Monitor for signs of pulmonary hypertension worsening. |
| Fertility Effects | No human data on fertility effects. In animal studies, no impairment of fertility was observed in male and female rats at doses up to 6 times the human exposure (based on AUC). |
| Clinical Pearls | Titrate slowly to avoid hypotension (especially with diuretics). Monitor for infusion site pain and infection. For subcutaneous route, rotate sites every 1-2 days. Avoid abrupt discontinuation; taper if needed due to risk of rebound pulmonary hypertension. |
| Patient Advice | Do not stop this medication suddenly; consult your doctor first. · Report any pain, redness, or swelling at the infusion site. · Avoid driving or operating heavy machinery until you know how this drug affects you due to possible dizziness. · Monitor for signs of low blood pressure such as lightheadedness or fainting. · Keep all appointments for blood pressure and lung function checks. |