Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
UPTRAVI vs ALFENTA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Uptravi (selexipag) is a prostacyclin receptor (IP receptor) agonist. Selexipag and its active metabolite, ACT-333679, selectively bind to the IP receptor, leading to vasodilation, inhibition of platelet aggregation, and antiproliferative effects on smooth muscle cells.
μ-opioid receptor agonist that activates G-protein coupled receptors to inhibit adenylate cyclase, decreasing c AMP production, leading to reduced neuronal excitability and pain transmission.
Treatment of pulmonary arterial hypertension (PAH, WHO Group I) to delay disease progression and reduce the risk of hospitalization,Off-label: None established
Induction and maintenance of anesthesia,Analgesic supplement during surgical procedures,Intravenous use for monitored anesthesia care (MAC)
Initial dose 200 mcg orally twice daily, titrated in increments of 200 mcg twice daily at weekly intervals to a maximum of 1600 mcg twice daily.
Intravenous: Initial dose 8-20 mcg/kg (0.5-1 min) then 0.5-3 mcg/kg/min or 3-5 mcg/kg q5-20min. For short procedures: 8-20 mcg/kg. For longer procedures: 50-75 mcg/kg followed by 0.5-3 mcg/kg/min.
Terminal elimination half-life is approximately 7–9 hours in healthy subjects, but prolonged in patients with hepatic impairment (Child-Pugh class A: ~11 hours; class B: ~16 hours). Steady-state is reached within 2–4 days of twice-daily dosing.
Terminal elimination half-life: 90–111 minutes (1.5–1.85 hours); prolonged in hepatic impairment.
Selexipag is hydrolyzed by carboxylesterases (mainly CES1 and CES2) to its active metabolite, ACT-333679. Both are further metabolized by CYP3A4 and CYP2C8. ACT-333679 is also a substrate for UGT1A3 and UGT2B7.
Hepatic via CYP3A4 to inactive metabolites; major metabolite is desmethylalfentanil (inactive).
Primarily hepatic metabolism; renal excretion of unchanged drug is <1%. Fecal excretion accounts for approximately 70% of total elimination, mainly as metabolites. Biliary excretion contributes to fecal elimination.
Primarily renal (urinary) elimination as metabolites; approximately 80% recovered in urine, 20% in feces.
99% bound to plasma proteins, primarily to albumin and alpha-1-acid glycoprotein.
Approximately 92% bound, primarily to alpha-1 acid glycoprotein and albumin.
Approximately 0.3 L/kg in healthy subjects, indicating distribution primarily within the vascular space and well-perfused tissues.
0.5–1.0 L/kg; reflects moderate tissue distribution; higher Vd in neonates and elderly.
Oral bioavailability is approximately 50–60% due to first-pass metabolism. Food does not significantly affect absorption.
Intravenous: 100%; intramuscular: approximately 90%; intrathecal: approximately 10% (due to systemic absorption following spinal administration).
No dose adjustment required for mild to moderate renal impairment (e GFR ≥15 m L/min/1.73 m²). Not studied in severe renal impairment (e GFR <15 m L/min/1.73 m²) or on dialysis; use caution.
No specific dose adjustment is recommended for renal impairment; however, alfentanil is primarily metabolized in the liver and its pharmacokinetics are not significantly altered in renal failure.
Mild hepatic impairment (Child-Pugh A): No dose adjustment. Moderate hepatic impairment (Child-Pugh B): Initial dose 200 mcg once daily, titrate cautiously. Severe hepatic impairment (Child-Pugh C): Not recommended.
In hepatic impairment (Child-Pugh class A, B, C): Reduce dose by 50% and titrate carefully due to prolonged elimination half-life. Consider lower initial doses and extended dosing intervals.
Not indicated for pediatric patients; safety and efficacy not established in patients <18 years.
Children (1-12 years): Induction of anesthesia: 10-20 mcg/kg IV; maintenance: 5-10 mcg/kg IV or infusion 0.5-1 mcg/kg/min. For neonates and infants: Dose individualization required; titrate to effect.
No specific dose adjustment recommended; elderly patients may have increased sensitivity, monitor closely.
Elderly patients (>65 years): Reduce initial dose by 30-50% and administer slowly. Due to decreased clearance and increased sensitivity, lower infusion rates (e.g., 0.3-0.5 mcg/kg/min) may be needed.
None.
Risk of respiratory depression, particularly in elderly or debilitated patients. Concomitant use with benzodiazepines or other CNS depressants may cause profound sedation, respiratory depression, coma, and death.
Pulmonary edema may occur; consider the possibility of pulmonary veno-occlusive disease (PVOD) if symptoms develop,Hepatic impairment: Avoid use in severe hepatic impairment (Child-Pugh Class C),Concomitant use with strong CYP2C8 inhibitors (e.g., gemfibrozil) increases exposure; reduce dose or consider alternative,Concomitant use with strong CYP3A4 inducers (e.g., rifampin) may reduce efficacy; monitor for loss of effect
Respiratory depression; abuse potential; hypotension; bradycardia; muscle rigidity; serotonin syndrome with concurrent serotonergic drugs; adrenal insufficiency; risk of withdrawal with prolonged use.
Severe hepatic impairment (Child-Pugh Class C),Concomitant use with strong CYP2C8 inhibitors (e.g., gemfibrozil)
Hypersensitivity to alfentanil or any component; significant respiratory insufficiency; severe asthma; paralytic ileus; concurrent use of MAOIs (or within 14 days); acute or postoperative pain management in children (except for procedural sedation).
Avoid grapefruit juice as it may increase systemic exposure to UPTRAVI. Take with or without food, but consistent timing with meals is recommended to maintain stable drug levels.
No known interactions with food. However, grapefruit juice may increase alfentanil serum concentrations due to CYP3A4 inhibition; avoid concurrent consumption.
In animal studies, UPTRAVI (selexipag) and its active metabolite showed developmental toxicity including reduced fetal weights and increased skeletal variations at maternal toxic doses. No adequate and well-controlled studies in pregnant women. Risk cannot be ruled out. First trimester: potential teratogenicity based on animal data. Second and third trimesters: may cause fetal harm due to pharmacological action (IP receptor agonist) potentially affecting uterine blood flow.
Alfentanil, a short-acting opioid analgesic, is classified as FDA Pregnancy Category C. No well-controlled studies in pregnant women exist. In animal studies, no teratogenic effects were observed at clinically relevant doses; however, high doses caused embryotoxicity and increased fetal mortality. Trimester-specific risks: First trimester - potential for minor malformations based on limited human data; second trimester - possible risk if used chronically; third trimester - prolonged use may lead to neonatal respiratory depression, withdrawal syndrome, or opioid dependence. Use only if benefits outweigh risks.
No data on presence in human milk, effects on breastfed infant, or milk production. M/P ratio is unknown. The active metabolite is potentially excreted in animal milk. Due to potential for serious adverse reactions, breastfeeding is not recommended during treatment and for at least 2 days after final dose.
Alfentanil is excreted into human breast milk in low concentrations. The milk-to-plasma (M/P) ratio is approximately 0.3. Estimated infant dose is <1% of maternal weight-adjusted dose, which is considered clinically insignificant. However, due to potential for neonatal opioid effects, caution is advised; monitor infant for drowsiness, respiratory depression, and feeding difficulties. Consider alternative analgesics with established safety profiles, such as acetaminophen or ibuprofen, for lactation.
No pharmacokinetic studies in pregnant women. Pregnancy may alter drug metabolism (e.g., increased clearance, Vd). No specific dose adjustment recommendations; use only if benefit outweighs risk. Close clinical monitoring for efficacy and tolerability.
Pregnancy can alter pharmacokinetics of alfentanil. Increased plasma volume and distribution may require higher doses to achieve same effect, while decreased plasma protein binding may increase free fraction, potentiating effects. Alpha-1-acid glycoprotein levels change in pregnancy, affecting binding. In third trimester, clearance may be increased by up to 50% due to enhanced hepatic metabolism. Therefore, dose adjustments may be needed: consider starting at low dose and titrating to effect, with close monitoring. For intravenous administration, typical adult doses (5-20 μg/kg) may need adjustments; no standard pregnancy-specific dosing exists. Use the lowest effective dose for the shortest duration. In labor, avoid high doses prior to delivery due to risk of neonatal respiratory depression.
Titrate to maximum tolerated dose up to 1600 mg twice daily. Monitor for signs of pulmonary edema (PPH with veno-occlusive disease). Co-administration with strong CYP2C8 inhibitors (e.g., gemfibrozil) reduces UPTRAVI clearance; decrease dose by 50% during co-administration. Avoid abrupt discontinuation; taper if possible. May cause orthostatic hypotension; assess blood pressure regularly. UPTRAVI is a prodrug of the active metabolite ACT-333679, a selective prostacyclin receptor (IP receptor) agonist.
Alfentanil is a potent, rapid-onset, short-acting opioid analgesic used primarily for induction and maintenance of anesthesia. Due to its high protein binding (90%) and rapid redistribution, it has a shorter duration of action than fentanyl, making it suitable for brief, painful procedures. It undergoes hepatic metabolism via CYP3A4, so concomitant use with CYP3A4 inhibitors like ketoconazole or erythromycin can prolong its effects. Use caution in elderly or hypovolemic patients due to increased risk of hypotension. Naloxone reverses respiratory depression. Alfentanil is 5-10 times less potent than fentanyl.
Take exactly as prescribed; do not crush or split tablets.,Do not stop taking this medication suddenly; consult your doctor if you need to discontinue.,Avoid grapefruit juice as it may increase drug exposure.,Report any severe headaches, jaw pain, or flushing to your healthcare provider.,Use caution when driving or operating machinery until you know how this medication affects you.,Store at room temperature away from moisture and heat.
This medication is given only by a healthcare professional in a hospital or surgical setting.,You may feel drowsy, dizzy, or nauseated after receiving this drug.,Report any difficulty breathing or slow heart rate to your healthcare provider immediately.,Avoid alcohol and sedatives for 24 hours after administration, as they can increase side effects.,Do not drive or operate machinery until the effects have fully worn off.
No interactions on record
"Propantheline, an anticholinergic agent, can competitively antagonize muscarinic acetylcholine receptors, potentially reducing gastrointestinal motility and secretion. Alfentanil, a mu-opioid receptor agonist, also decreases gastrointestinal motility through central and peripheral opioid receptors. Concomitant use may synergistically inhibit peristalsis, leading to severe constipation, paralytic ileus, or delayed gastric emptying, which can increase the risk of aspiration and complicate anesthesia recovery."
"Alfentanil, a potent opioid analgesic, can cause significant hypotension and respiratory depression. When combined with furosemide, a loop diuretic that reduces blood volume and vascular resistance, there is a synergistic decrease in blood pressure, which may precipitate cardiovascular collapse, especially in patients with compromised circulatory reserves. Additionally, furosemide may enhance the sedative and respiratory depressant effects of alfentanil, leading to increased risk of respiratory acidosis and altered mental status."
"Alfentanil, a potent mu-opioid receptor agonist, can enhance the bradycardic effects of nebivolol, a beta-1 selective blocker with additional nitric oxide-mediated vasodilation. The combination may lead to excessive slowing of heart rate, reduced cardiac output, and potential hemodynamic instability, particularly in patients with underlying cardiac conduction abnormalities or hypovolemia."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about UPTRAVI vs ALFENTA, answered by our medical review team.
UPTRAVI is a Prostacyclin Receptor Agonist that works by Uptravi (selexipag) is a prostacyclin receptor (IP receptor) agonist. Selexipag and its active metabolite, ACT-333679, selectively bind to the IP receptor, leading to vasodilation, inhibition of platelet aggregation, and antiproliferative effects on smooth muscle cells.. ALFENTA is a Opioid Analgesic that works by μ-opioid receptor agonist that activates G-protein coupled receptors to inhibit adenylate cyclase, decreasing c AMP production, leading to reduced neuronal excitability and pain transmission.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between UPTRAVI and ALFENTA depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of UPTRAVI is: Initial dose 200 mcg orally twice daily, titrated in increments of 200 mcg twice daily at weekly intervals to a maximum of 1600 mcg twice daily.. The standard adult dose of ALFENTA is: Intravenous: Initial dose 8-20 mcg/kg (0.5-1 min) then 0.5-3 mcg/kg/min or 3-5 mcg/kg q5-20min. For short procedures: 8-20 mcg/kg. For longer procedures: 50-75 mcg/kg followed by 0.5-3 mcg/kg/min.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between UPTRAVI and ALFENTA in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. UPTRAVI is classified as Category C. In animal studies, UPTRAVI (selexipag) and its active metabolite showed developmental toxicity including reduced fetal weights and increased skeletal variations at maternal toxic d. ALFENTA is classified as Category C. Alfentanil, a short-acting opioid analgesic, is classified as FDA Pregnancy Category C. No well-controlled studies in pregnant women exist. In animal studies, no teratogenic effect. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.