Comparative Pharmacology
Head-to-head clinical analysis: NALOXONE HYDROCHLORIDE versus VIVITROL.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NALOXONE HYDROCHLORIDE versus VIVITROL.
NALOXONE HYDROCHLORIDE 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 intravenous, intramuscular, or subcutaneous every 2 to 3 minutes as needed for opioid reversal; may repeat until response achieved. For continuous infusion, 0.25-6.25 mg/hour IV.
380 mg intramuscularly every 4 weeks, alternating gluteal injections.
None Documented
None Documented
Terminal elimination half-life is 1–1.5 hours in adults; shorter in neonates (approx. 3 hours due to immature clearance). Clinically, rapid decline limits duration of antagonism.
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) with renal excretion of metabolites. ~70% as naloxone-3-glucuronide in urine, <5% unchanged. Minor fecal elimination (<10%).
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