Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
NALOXONE HYDROCHLORIDE AND PENTAZOCINE HYDROCHLORIDE vs ACYLANID
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Pentazocine is a mixed agonist-antagonist opioid that binds to mu-opioid receptors (partial agonist) and kappa-opioid receptors (agonist), producing analgesia. Naloxone is a pure opioid antagonist that competitively blocks mu, kappa, and delta receptors; when administered orally, naloxone undergoes extensive first-pass metabolism, reducing systemic absorption and primarily blocking the effects of pentazocine if the combination is misused parenterally.
Acylanid is a cardiac glycoside that inhibits the Na+/K+-ATPase pump, leading to increased intracellular sodium and calcium concentrations, which enhances myocardial contractility.
Moderate to severe pain relief; combinations are used to reduce abuse potential.
Heart failure,Atrial fibrillation,Atrial flutter
Oral: One tablet (naloxone 0.5 mg / pentazocine 50 mg) every 3-4 hours as needed for pain; maximum 12 tablets daily.
0.1 mg IV bolus over 5 minutes, followed by 0.1 mg IV after 1 hour if needed; then 0.1-0.2 mg orally every 6-8 hours for maintenance. Maximum cumulative dose: 0.4 mg IV.
Pentazocine has an elimination half-life of 2-3 hours in healthy adults, which may be prolonged in patients with hepatic impairment. Naloxone has a terminal half-life of 0.5-1.5 hours in adults, with a rapid decline in plasma levels; the short half-life limits its duration of opioid antagonism.
Terminal half-life 33–36 hours (anuric patients up to 110 hours); requires dose adjustment in renal impairment.
Pentazocine is metabolized primarily by hepatic conjugation (glucuronidation) and oxidation via CYP2C19 and CYP2D6; naloxone is extensively metabolized by the liver, primarily via glucuronidation (UGT2B7).
Hepatic metabolism via hydrolysis and conjugation; not significantly metabolized by CYP enzymes.
Pentazocine is primarily metabolized in the liver and excreted in urine as conjugates of glucuronide and sulfate, with about 60% of a dose excreted renally within 24 hours as metabolites and unchanged drug (less than 5% unchanged). Naloxone undergoes extensive hepatic metabolism to naloxone-3-glucuronide, which is excreted renally; approximately 50% of a dose is excreted as conjugates in urine within 6 hours.
Renal (≈70% as unchanged drug), biliary/fecal (≈30%)
Pentazocine: Approximately 35-65% bound to plasma proteins (mainly albumin). Naloxone: Approximately 32-45% bound to plasma proteins (mainly albumin).
25–30% bound to albumin.
Pentazocine: Vd ~2-3 L/kg, indicating extensive tissue distribution. Naloxone: Vd ~2-3 L/kg, also indicating wide distribution.
7.5–10 L/kg; wide distribution indicating extensive tissue binding.
Oral pentazocine: 20-30% due to first-pass metabolism. Intramuscular pentazocine: 100%. Subcutaneous pentazocine: 100%. Oral naloxone: <2% due to extensive first-pass metabolism. Intramuscular and subcutaneous naloxone: 100%. Intravenous: 100% for both.
Oral: 70–85% (variable, dependent on gastrointestinal absorption).
GFR 30-50 m L/min: Administer every 6 hours; GFR 10-29 m L/min: Administer every 8-12 hours; GFR <10 m L/min: Administer every 12 hours or consider alternative.
GFR <30 m L/min: reduce dose by 50% and extend dosing interval to every 12-24 hours. GFR 30-50 m L/min: consider 25% dose reduction. Monitor digoxin levels.
Child-Pugh Class A: No adjustment; Child-Pugh Class B: Reduce dose by 50% or extend interval; Child-Pugh Class C: Avoid use.
Child-Pugh Class B: reduce dose by 25-50%. Child-Pugh Class C: use with caution, reduce dose by 50% and monitor levels. Not recommended in severe hepatic impairment.
Not recommended for children under 12 years. For older children (≥12 years): Pentazocine 50 mg (with naloxone 0.5 mg) orally every 3-4 hours as needed; maximum 6 tablets daily.
Loading dose: 10-15 mcg/kg IV over 5 minutes. Maintenance: 5-10 mcg/kg orally every 8-12 hours. Maximum daily dose: 250 mcg in children <2 years, 500 mcg in older children.
Initiate with half the usual adult dose (one-half tablet) and titrate carefully due to increased sensitivity and risk of respiratory depression.
Initiate with 50% of usual adult dose due to reduced renal function and increased sensitivity. Maximum loading dose: 0.2 mg IV. Maintenance: 0.1 mg every 12 hours. Monitor electrolytes and ECG.
Risk of respiratory depression, particularly in elderly, cachectic, or debilitated patients; risk of addiction, abuse, and misuse; risk of neonatal opioid withdrawal syndrome with prolonged use during pregnancy; risk of life-threatening respiratory depression when used with benzodiazepines or other CNS depressants.
None.
Respiratory depression; hypotension; increased intracranial pressure; seizure risk (pentazocine); opioid-induced hyperalgesia; adrenal insufficiency; severe hypotension; interaction with MAOIs; risk of dependence and withdrawal; gastrointestinal obstruction; impaired renal or hepatic function; head injury.
Risk of digitalis toxicity; monitor renal function and electrolytes; caution in hypokalemia, hypomagnesemia, and hypercalcemia.
Hypersensitivity to pentazocine or naloxone; significant respiratory depression; acute or severe bronchial asthma; GI obstruction; known or suspected paralytic ileus; patients receiving MAOIs or within 14 days.
Ventricular fibrillation,Hypersensitivity to cardiac glycosides,Digitalis toxicity
No specific food interactions are reported for this combination. However, grapefruit juice may theoretically affect metabolism via CYP3A4 (pentazocine is metabolized by CYP3A4), but clinical significance is unknown. Advise patients to maintain a consistent diet.
Avoid high-potassium foods (bananas, oranges, spinach) unless directed; hypokalemia increases toxicity. Take with food to reduce GI upset. Do not take with high-fiber meals as may reduce absorption.
Pentazocine crosses the placenta; naloxone has limited placental transfer. No well-controlled human studies. First trimester: Risk cannot be excluded; avoid if possible. Second/Third trimester: Chronic use may cause fetal dependence; neonatal withdrawal syndrome reported. High doses near term may cause neonatal respiratory depression.
Acylanid is a cardiac glycoside with limited data in pregnancy. First trimester: No specific malformations reported, but potential for fetal cardiac effects due to mechanism. Second and third trimesters: Maternal toxicity (arrhythmias, electrolyte disturbances) may cause fetal hypoxia or growth restriction. Avoid toxicity. Category C.
Pentazocine is excreted in breast milk in small amounts (estimated relative infant dose <3%). Naloxone is poorly bioavailable orally. Generally considered compatible with breastfeeding; monitor infant for sedation or poor feeding. M/P ratio for pentazocine is approximately 1.0.
Acylanid is excreted into breast milk in low amounts (M/P ratio not established; estimated <1% of maternal dose). No adverse effects reported in nursing infants. Use with caution, monitor infant for bradycardia or arrhythmias.
No established dose adjustments for pregnancy; however, pharmacokinetic changes (increased volume of distribution, enhanced clearance) may require higher or more frequent doses of pentazocine for adequate analgesia. Use lowest effective dose and shortest duration.
Increased volume of distribution and renal clearance in pregnancy may reduce serum levels; monitor drug levels and adjust dose to maintain therapeutic range (0.5-2 ng/m L). Start at lower doses if hypokalemia or preeclampsia present.
Naloxone in this fixed-dose combination is included to deter opioid abuse by reversing euphoria. The pentazocine component is a mixed agonist-antagonist opioid; naloxone has poor oral bioavailability but becomes active parenterally, precipitating withdrawal in opioid-dependent individuals. Use with caution in patients with impaired renal or hepatic function. Monitor for respiratory depression, especially in opioid-naive patients, as pentazocine alone can cause respiratory depression.
Acylanid (lanatoside C) is a digitalis glycoside with rapid onset (IV 10-30 min) and moderate duration; use in atrial fibrillation with rapid ventricular response, especially in acute settings. Monitor renal function due to renal elimination; toxicity risk increases with hypokalemia, hypomagnesemia, hypercalcemia. Adjust dose in renal impairment (Cr Cl <50 m L/min). Therapeutic drug monitoring: target serum level 0.5-2 ng/m L (drawn >6-8 hours post-dose).
Take exactly as prescribed; do not crush or inject tablets, as injected naloxone can cause severe withdrawal in opioid-dependent individuals.,This medication contains naloxone to discourage misuse; injection will cause withdrawal symptoms.,Report any signs of withdrawal (e.g., nausea, vomiting, sweating, agitation) or breathing difficulty.,Avoid alcohol and other central nervous system depressants as they increase risk of respiratory depression.,Do not use with other opioids unless directed, as effects are unpredictable.,Keep out of reach of children; accidental ingestion may cause severe respiratory depression.
Take exactly as prescribed; do not skip doses or double up. Missed dose: take if within 12 hours, otherwise skip.,Monitor for signs of toxicity: nausea, vomiting, diarrhea, visual disturbances (yellow-green halos, blurred vision), confusion, irregular heartbeat.,Avoid OTC medications without consulting prescriber, especially antacids, laxatives, and antiarrhythmics.,Keep regular appointments for blood tests (digoxin level, kidney function, electrolytes).,Report weight gain >2 lbs/day, swelling, shortness of breath, or palpitations.
"Cobicistat is a potent CYP3A4 inhibitor used to boost the pharmacokinetics of antiretroviral agents like atazanavir and darunavir. Naloxone primarily undergoes glucuronidation via UGT1A6 and UGT2B7, with minor CYP3A4 metabolism. Concomitant use with Cobicistat may modestly increase naloxone exposure due to CYP3A4 inhibition, but this is unlikely to be clinically significant given naloxone's wide therapeutic index and short half-life."
"Fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), is primarily metabolized by cytochrome P450 (CYP) 1A2 and 2D6. Naloxone, an opioid antagonist, is reported to inhibit CYP1A2, potentially decreasing the clearance of fluvoxamine. This interaction may lead to increased fluvoxamine plasma concentrations, elevating the risk of serotonin syndrome, QT prolongation, and other dose-dependent adverse effects, especially in patients receiving high doses or those with hepatic impairment."
"Naloxone, an opioid receptor antagonist, may inhibit the cytochrome P450 isoenzyme CYP3A4, which is responsible for the metabolism of ivacaftor. Concomitant administration can lead to reduced clearance of ivacaftor, resulting in elevated serum concentrations. This increase may potentiate the therapeutic effects and adverse reactions of ivacaftor, such as hepatotoxicity and QT prolongation."
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about NALOXONE HYDROCHLORIDE AND PENTAZOCINE HYDROCHLORIDE vs ACYLANID, answered by our medical review team.
NALOXONE HYDROCHLORIDE AND PENTAZOCINE HYDROCHLORIDE is a Opioid Agonist-Antagonist that works by Pentazocine is a mixed agonist-antagonist opioid that binds to mu-opioid receptors (partial agonist) and kappa-opioid receptors (agonist), producing analgesia. Naloxone is a pure opioid antagonist that competitively blocks mu, kappa, and delta receptors; when administered orally, naloxone undergoes extensive first-pass metabolism, reducing systemic absorption and primarily blocking the effects of pentazocine if the combination is misused parenterally.. ACYLANID is a Cardiac Glycoside that works by Acylanid is a cardiac glycoside that inhibits the Na+/K+-ATPase pump, leading to increased intracellular sodium and calcium concentrations, which enhances myocardial contractility.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between NALOXONE HYDROCHLORIDE AND PENTAZOCINE HYDROCHLORIDE and ACYLANID 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 NALOXONE HYDROCHLORIDE AND PENTAZOCINE HYDROCHLORIDE is: Oral: One tablet (naloxone 0.5 mg / pentazocine 50 mg) every 3-4 hours as needed for pain; maximum 12 tablets daily.. The standard adult dose of ACYLANID is: 0.1 mg IV bolus over 5 minutes, followed by 0.1 mg IV after 1 hour if needed; then 0.1-0.2 mg orally every 6-8 hours for maintenance. Maximum cumulative dose: 0.4 mg IV.. 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 NALOXONE HYDROCHLORIDE AND PENTAZOCINE HYDROCHLORIDE and ACYLANID 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. NALOXONE HYDROCHLORIDE AND PENTAZOCINE HYDROCHLORIDE is classified as Category A/B. Pentazocine crosses the placenta; naloxone has limited placental transfer. No well-controlled human studies. First trimester: Risk cannot be excluded; avoid if possible. Second/Thi. ACYLANID is classified as Category C. Acylanid is a cardiac glycoside with limited data in pregnancy. First trimester: No specific malformations reported, but potential for fetal cardiac effects due to mechanism. Secon. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.