Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ALFENTANIL vs LUPKYNIS
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Alfentanil is a potent, short-acting synthetic opioid analgesic that primarily acts as a mu-opioid receptor agonist. It binds to mu-opioid receptors in the central nervous system, leading to G-protein coupled activation of inwardly rectifying potassium channels and inhibition of voltage-gated calcium channels, resulting in hyperpolarization and reduced neurotransmitter release. This produces analgesia, sedation, and respiratory depression.
Calcineurin inhibitor immunosuppressant that binds to cyclophilin A, inhibiting calcineurin activity, which prevents dephosphorylation and activation of nuclear factor of activated T-cells (NFAT), thereby reducing cytokine production and T-cell activation.
Analgesic adjunct during general anesthesia,Induction of anesthesia,Maintenance of anesthesia for short surgical procedures,Off-label: Procedural sedation in monitored settings
Treatment of lupus nephritis in combination with a background immunosuppressive therapy
Initial IV bolus of 5-20 mcg/kg; maintenance infusion of 0.5-1.5 mcg/kg/min; incremental boluses of 5-10 mcg/kg as needed. Induction of anesthesia: 50-100 mcg/kg IV.
23.7 mg orally twice daily with food.
Terminal elimination half-life: 90–111 minutes (1.5–1.85 hours). Clinically, context-sensitive half-time is short (~40 min after 3-hour infusion) due to rapid redistribution and metabolism.
Terminal elimination half-life approximately 30 hours; supports once-daily dosing; steady-state reached by day 4.
Alfentanil is primarily metabolized by hepatic cytochrome P450 enzymes, mainly CYP3A4, through oxidative N-dealkylation and O-demethylation to inactive metabolites.
Primarily metabolized by CYP3A4; minor contribution from CYP3A5.
Primarily hepatic metabolism via CYP3A4; <1% excreted unchanged in urine; metabolites (mainly noralfentanil) excreted renally. Biliary/fecal excretion of metabolites accounts for ~30%.
Primarily hepatic metabolism; <1% excreted unchanged in urine; approximately 66% of total radioactivity recovered in feces (mainly metabolites) and 22% in urine (mainly metabolites).
~92% bound primarily to alpha-1-acid glycoprotein (AAG) and albumin.
Greater than 99% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein.
Vd: 0.4–1.0 L/kg (mean ~0.75 L/kg). Moderate Vd reflecting rapid distribution to tissues, especially brain and muscle.
Apparent Vd/F ~24 L (approximately 0.34 L/kg assuming 70 kg); indicates distribution into tissues.
IV: 100%. IM: ~90%. Epidural: ~30–50% due to local uptake and redistribution. No significant oral bioavailability.
Oral bioavailability approximately 35% (range 20–50%) under fasting conditions; high-fat meal reduces Cmax and AUC by about 50%.
GFR 10-50 m L/min: administer with caution, consider dose reduction of 25-50%; GFR <10 m L/min: reduce dose by 50% and extend dosing interval.
No dose adjustment required for GFR ≥30 m L/min. Avoid use in severe renal impairment (GFR <30 m L/min) due to lack of data.
Child-Pugh class A: no adjustment needed; Child-Pugh class B: reduce dose by 50%; Child-Pugh class C: reduce dose by 75%.
Child-Pugh Class A: No adjustment. Child-Pugh Class B: Reduce dose to 15.8 mg orally twice daily. Child-Pugh Class C: Not recommended.
Initial IV bolus of 5-20 mcg/kg; maintenance infusion of 0.5-2 mcg/kg/min. For neonates, reduce dose by 30-50% due to immature clearance.
Safety and efficacy not established in pediatric patients; no approved dose.
Reduce initial IV bolus by 30-50% to 3-10 mcg/kg; titrate carefully; monitor for prolonged sedation and respiratory depression.
No specific dose adjustment required; monitor renal function due to age-related decline.
Risk of respiratory depression: Alfentanil can cause severe, life-threatening, or fatal respiratory depression. Monitor for respiratory depression, especially during initiation or following dose increases. Accidental ingestion of even one dose can be fatal. Concomitant use with central nervous system depressants (e.g., benzodiazepines, alcohol) may increase risk. Alfentanil is an opioid agonist and a Schedule II controlled substance with high potential for abuse and addiction.
Increased risk of infection and lymphoma; increased risk of nephrotoxicity and hypertension; increased risk of neurotoxicity.
Respiratory depression: Potentially fatal; monitor oxygenation and ventilation.,Abuse potential: Schedule II controlled substance; risk of addiction, abuse, and diversion.,Concomitant use with CNS depressants: Increases risk of profound sedation, respiratory depression, coma, and death; limit use or monitor closely.,Geriatric and cachectic patients: Increased sensitivity; reduce initial dose.,Hepatic impairment: Alfentanil clearance is reduced in patients with cirrhosis; consider dose adjustment.,Bradycardia and hypotension: Use with caution in patients with hypovolemia or reduced cardiac reserve.,Serotonin syndrome: Risk with concurrent serotonergic drugs (e.g., MAOIs, SSRIs, triptans); monitor for symptoms.,Withdrawal: Prolonged use may lead to physical dependence; taper dose gradually.
Nephrotoxicity and hypertension require regular monitoring. Neurotoxicity including posterior reversible encephalopathy syndrome (PRES). Increased susceptibility to infections including opportunistic infections. Malignancies including lymphoma. Monitor for Epstein-Barr virus serology. Use with caution with CYP3A4 inhibitors and inducers. Avoid live vaccines.
Hypersensitivity to alfentanil, fentanyl, or any opioid,Significant respiratory depression (e.g., acute asthma, COPD in acute exacerbation),Acute or severe bronchial asthma,Suspected or known paralytic ileus,MAO inhibitor use within 14 days (serotonin syndrome risk),Myasthenia gravis (relative contraindication due to risk of respiratory muscle weakness),Morbid obesity with sleep apnea (relative contraindication; increased risk of respiratory depression)
Concurrent use with chronic immunosuppressive therapies other than mycophenolate mofetil (MMF) or mycophenolic acid (MPA). Known hypersensitivity to voclosporin or any component of the formulation.
No significant food interactions known. Avoid grapefruit and grapefruit juice as they may inhibit CYP3A4 metabolism, potentially prolonging effects.
Avoid grapefruit and grapefruit juice as they increase voclosporin exposure. No other specific food interactions are known.
Alfentanil is an opioid analgesic; limited human data. No clear evidence of major malformations, but third trimester use may cause neonatal opioid withdrawal syndrome (NOWS). Avoid prolonged use or high doses near term; use during labor may cause respiratory depression in neonate.
LUPKYNIS (voclosporin) is a calcineurin inhibitor. Based on animal studies, there is a risk of fetal harm in all trimesters. In rats and rabbits, voclosporin administration during organogenesis resulted in increased embryofetal mortality and reduced fetal weight at maternally toxic doses. There are no adequate human studies. Avoid use during pregnancy unless potential benefit outweighs risk.
Alfentanil is excreted into breast milk in very low concentrations; estimated relative infant dose is low (<2% of maternal weight-adjusted dose). M/P ratio not determined in humans. Compatible with breastfeeding with caution; monitor infant for drowsiness, feeding difficulties.
It is unknown if voclosporin is excreted in human milk. In animal studies, voclosporin and its metabolites were detected in milk of lactating rats. No M/P ratio available for humans. Due to potential for serious adverse reactions in nursing infants, advise women not to breastfeed during treatment and for 4 weeks after last dose.
Pregnancy can alter alfentanil pharmacokinetics: increased volume of distribution, decreased plasma clearance, prolonged elimination half-life. Dose reduction may be needed for prolonged use; titrate to effect. During labor, use smallest effective dose.
No specific dose adjustments are established for pregnancy. However, pregnancy can increase voclosporin clearance due to expanded plasma volume and enhanced metabolism. Consider therapeutic drug monitoring if available, and adjust dose to maintain therapeutic trough levels (target 30-60 ng/m L) as needed.
Alfentanil is a potent, short-acting synthetic opioid (4-5 times more potent than fentanyl) with rapid onset (1-2 min) and brief duration (5-10 min). Primarily used for induction and maintenance of anesthesia, especially in short procedures. Requires careful monitoring of respiratory depression and chest wall rigidity, particularly during rapid IV administration. Hepatic metabolism (CYP3A4) affected by liver disease; reduce dose. Decrease dose in elderly and hypovolemic patients. Not recommended for chronic pain due to short half-life.
Monitor for hematuria, proteinuria, and e GFR during treatment. Lupkynis (voclosporin) is a calcineurin inhibitor; do not co-administer with other CNIs or strong CYP3A4 inhibitors. Reduce dose in patients with e GFR <45 m L/min per 1.73 m². Concomitant use with mycophenolate mofetil and corticosteroids is standard. Check blood pressure and serum potassium regularly. Live vaccines contraindicated.
This medication causes drowsiness and dizziness; avoid driving or operating machinery for at least 24 hours after administration.,Report any difficulty breathing, chest tightness, or feeling faint immediately.,Alfentanil is used only in hospital settings under direct supervision of healthcare professionals.,Inform your doctor if you have a history of liver disease, lung disease, or drug/alcohol abuse.,Do not consume alcohol or other sedatives while under the effects of alfentanil.
Take exactly as prescribed; do not stop or change dose without consulting your doctor.,You will need regular blood and urine tests to monitor kidney function and drug levels.,Report any signs of infection (fever, sore throat), high blood pressure (severe headache, vision changes), or changes in urine output/color.,Avoid grapefruit and grapefruit juice during treatment.,Do not receive live vaccines while taking this medication.,Use effective contraception during treatment and for 12 weeks after last dose if of childbearing potential.,Tell your doctor about all medications, including over-the-counter drugs and supplements.
"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."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ALFENTANIL vs LUPKYNIS, answered by our medical review team.
ALFENTANIL is a Opioid Analgesic that works by Alfentanil is a potent, short-acting synthetic opioid analgesic that primarily acts as a mu-opioid receptor agonist. It binds to mu-opioid receptors in the central nervous system, leading to G-protein coupled activation of inwardly rectifying potassium channels and inhibition of voltage-gated calcium channels, resulting in hyperpolarization and reduced neurotransmitter release. This produces analgesia, sedation, and respiratory depression.. LUPKYNIS is a Calcineurin Inhibitor Immunosuppressant that works by Calcineurin inhibitor immunosuppressant that binds to cyclophilin A, inhibiting calcineurin activity, which prevents dephosphorylation and activation of nuclear factor of activated T-cells (NFAT), thereby reducing cytokine production and T-cell activation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ALFENTANIL and LUPKYNIS 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 ALFENTANIL is: Initial IV bolus of 5-20 mcg/kg; maintenance infusion of 0.5-1.5 mcg/kg/min; incremental boluses of 5-10 mcg/kg as needed. Induction of anesthesia: 50-100 mcg/kg IV.. The standard adult dose of LUPKYNIS is: 23.7 mg orally twice daily with food.. 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 ALFENTANIL and LUPKYNIS 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. ALFENTANIL is classified as Category C. Alfentanil is an opioid analgesic; limited human data. No clear evidence of major malformations, but third trimester use may cause neonatal opioid withdrawal syndrome (NOWS). Avoid. LUPKYNIS is classified as Category C. LUPKYNIS (voclosporin) is a calcineurin inhibitor. Based on animal studies, there is a risk of fetal harm in all trimesters. In rats and rabbits, voclosporin administration during . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.