Comparative Pharmacology
Head-to-head clinical analysis: NALOXONE HCL versus VIVITROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NALOXONE HCL versus VIVITROL.
NALOXONE HCL vs VIVITROL
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Competitive antagonist at mu, kappa, and delta opioid receptors, reversing opioid-induced respiratory depression and analgesia.
Naltrexone, as the active moiety of VIVITROL, is a competitive antagonist at opioid receptors (mu, kappa, and delta), blocking the euphoric effects of alcohol and opioids. It also modulates the hypothalamic-pituitary-adrenal axis and dopamine pathways implicated in alcohol craving.
0.4 mg to 2 mg IV, IM, or subcutaneously, may repeat every 2-3 minutes as needed. For continuous infusion, IV infusion rate of 0.25-6.25 mg/hour.
380 mg intramuscularly every 4 weeks, alternating gluteal injections.
None Documented
None Documented
Terminal elimination half-life is 1.0-1.5 hours in adults. In neonates, half-life is prolonged (3-4 hours) due to immature hepatic function. Clinically, the short half-life necessitates repeated or continuous dosing to reverse opioid effects lasting longer than naloxone's duration.
Naltrexone terminal half-life: 4-13 hours (mean 9.7 h). Active metabolite 6-β-naltrexol: 10-15 hours. Clinically, naltrexone concentrations are sustained for ~30 days after IM injection.
Primarily hepatic metabolism (glucuronidation). Renal excretion accounts for approximately 50% of total clearance, with biliary/fecal elimination contributing 20-30%. Unchanged naloxone in urine is <5%.
Naltrexol (6-β-naltrexol) and naltrexone: primarily renal (60-70% as metabolites, <5% as unchanged drug); biliary/fecal (minor route, <10%).
Category A/B
Category C
Opioid Antagonist
Opioid Antagonist