Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
DILAUDID-HP vs ALFENTA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Hydromorphone is a full mu-opioid receptor agonist with high affinity for mu-opioid receptors, producing analgesia, euphoria, and sedation. It also binds to kappa and delta opioid receptors with lower affinity.
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.
Management of pain severe enough to require an opioid analgesic and for which alternative treatments are inadequate (FDA-approved),Off-label: Treatment of acute pain, postoperative pain, cancer pain, and breakthrough pain
Induction and maintenance of anesthesia,Analgesic supplement during surgical procedures,Intravenous use for monitored anesthesia care (MAC)
Initial dose: 0.2-0.6 mg IV/IM/SC every 2-4 hours as needed; usual adult dose: 0.2-0.4 mg IV/IM/SC. Oral: 1-2 mg every 3-6 hours. Dose titration based on pain severity.
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: 2.3–4 hours. In clinical context, consistent with dosing interval of 4–6 hours for immediate-release formulations; prolonged in hepatic or renal impairment.
Terminal elimination half-life: 90–111 minutes (1.5–1.85 hours); prolonged in hepatic impairment.
Hydromorphone is extensively metabolized in the liver via glucuronidation to hydromorphone-3-glucuronide (major metabolite) and to a lesser extent via reduction to dihydroisomorphine and dihydromorphine. Minor CYP2C9 and CYP3A4 involvement.
Hepatic via CYP3A4 to inactive metabolites; major metabolite is desmethylalfentanil (inactive).
Renal: predominantly as hydromorphone-3-glucuronide (H3G), unchanged hydromorphone (<6%), and other metabolites. Biliary/fecal: minimal.
Primarily renal (urinary) elimination as metabolites; approximately 80% recovered in urine, 20% in feces.
Approximately 20–30%, primarily to albumin.
Approximately 92% bound, primarily to alpha-1 acid glycoprotein and albumin.
1.2–1.8 L/kg. Indicates extensive tissue distribution, consistent with a lipophilic opioid.
0.5–1.0 L/kg; reflects moderate tissue distribution; higher Vd in neonates and elderly.
Oral: 24–51% (first-pass metabolism); Intramuscular: 96% (relative to IV).
Intravenous: 100%; intramuscular: approximately 90%; intrathecal: approximately 10% (due to systemic absorption following spinal administration).
GFR 30-60 m L/min: reduce dose by 25-50%; GFR 10-29 m L/min: administer 50-75% of normal dose every 6-8 hours; GFR <10 m L/min: administer 25-50% of normal dose every 8-12 hours.
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.
Child-Pugh Class A: no adjustment; Child-Pugh Class B: reduce initial dose by 50%; Child-Pugh Class C: avoid use or reduce dose by 75% with extended dosing interval.
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.
Children >2 years: 0.1-0.2 mg/kg IV/IM/SC every 4-6 hours; maximum single dose 2 mg. Neonates/infants: 0.03-0.05 mg/kg IV/IM/SC every 4-6 hours.
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.
Initial dose: 0.1-0.2 mg IV/IM/SC every 4-6 hours; reduce dose by 50% compared to younger adults; titrate cautiously due to increased sensitivity and risk of respiratory depression.
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.
WARNING: ADDICTION, ABUSE, AND MISUSE; LIFE-THREATENING RESPIRATORY DEPRESSION; ACCIDENTAL INGESTION; NEONATAL OPIOID WITHDRAWAL SYNDROME; RISKS FROM CONCOMITANT USE WITH BENZODIAZEPINES OR OTHER CNS DEPRESSANTS; and RISKS OF USE IN PATIENTS WITH HEAD INJURY OR INCREASED INTRACRANIAL PRESSURE.
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.
Addiction, abuse, and misuse,Life-threatening respiratory depression,Accidental ingestion,Neonatal opioid withdrawal syndrome,Risks from concomitant use with benzodiazepines or other CNS depressants,Adrenal insufficiency,Severe hypotension,Gastrointestinal effects (constipation, ileus),Seizures,Withdrawal
Respiratory depression; abuse potential; hypotension; bradycardia; muscle rigidity; serotonin syndrome with concurrent serotonergic drugs; adrenal insufficiency; risk of withdrawal with prolonged use.
Significant respiratory depression,Acute or severe bronchial asthma in an unmonitored setting or in absence of resuscitative equipment,Known or suspected gastrointestinal obstruction, including paralytic ileus,Hypersensitivity to hydromorphone or any component of the product
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 alcohol while taking DILAUDID-HP, as it can potentiate CNS depression and increase the risk of respiratory depression. Grapefruit juice may inhibit CYP2D6 and CYP3A4 metabolism, potentially increasing hydromorphone levels; avoid concurrent consumption. High-fat meals may delay absorption; maintain consistent timing with or without food.
No known interactions with food. However, grapefruit juice may increase alfentanil serum concentrations due to CYP3A4 inhibition; avoid concurrent consumption.
FDA Pregnancy Category C. First trimester: No well-controlled human studies; animal studies have shown teratogenicity at high doses. Second and third trimesters: Chronic maternal use may lead to neonatal opioid withdrawal syndrome (NOWS) and respiratory depression at birth. Avoid use during labor due to risk of neonatal respiratory depression.
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.
Hydromorphone is excreted into breast milk. The milk-to-plasma (M/P) ratio is approximately 2.6. Limited data suggest low levels, but use caution due to potential for infant sedation and respiratory depression. The American Academy of Pediatrics considers hydromorphone compatible with breastfeeding if used short-term at low doses.
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.
Pregnancy does not significantly alter hydromorphone pharmacokinetics, but dose adjustments may be needed due to increased pain or opioid tolerance. Use lowest effective dose for shortest duration. Monitor for respiratory depression and adjust accordingly.
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.
DILAUDID-HP (high-potency hydromorphone) is indicated for opioid-tolerant patients only; 1 mg DILAUDID-HP is equivalent to 4 mg standard hydromorphone. Use with extreme caution in patients with respiratory compromise, COPD, or cor pulmonale. Avoid in patients with paralytic ileus or suspected GI obstruction. Monitor for serotonin syndrome when co-administered with serotonergic drugs. For PCA use, ensure proper programming to prevent overdose. Naloxone is the reversal agent; may require higher doses due to high potency.
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.
This is a high-potency opioid; take exactly as prescribed and never increase dose without consulting your doctor.,Do not break, crush, or chew tablets; swallow whole to avoid rapid release of the drug.,Avoid alcohol and other central nervous system depressants (e.g., benzodiazepines, sedatives) as they can increase the risk of severe drowsiness, respiratory depression, and death.,Do not stop taking abruptly; withdrawal symptoms may occur. Consult your doctor for a tapering plan.,Constipation is a common side effect; maintain adequate fluid intake, fiber, and consider stool softeners or laxatives as needed.,Store securely out of reach of children and pets; properly dispose of unused medication at a take-back location.,Seek emergency medical attention if you experience difficulty breathing, extreme drowsiness, confusion, or fainting.,This medication may impair your ability to drive or operate machinery; avoid such activities until you know how it affects you.
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 DILAUDID-HP vs ALFENTA, answered by our medical review team.
DILAUDID-HP is a Opioid Analgesic that works by Hydromorphone is a full mu-opioid receptor agonist with high affinity for mu-opioid receptors, producing analgesia, euphoria, and sedation. It also binds to kappa and delta opioid receptors with lower affinity.. 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 DILAUDID-HP and ALFENTA depend on the specific clinical indication. These are both Opioid Analgesic agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of DILAUDID-HP is: Initial dose: 0.2-0.6 mg IV/IM/SC every 2-4 hours as needed; usual adult dose: 0.2-0.4 mg IV/IM/SC. Oral: 1-2 mg every 3-6 hours. Dose titration based on pain severity.. 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 DILAUDID-HP 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. DILAUDID-HP is classified as Category C. FDA Pregnancy Category C. First trimester: No well-controlled human studies; animal studies have shown teratogenicity at high doses. Second and third trimesters: Chronic maternal u. 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.