Comparative Pharmacology
Head-to-head clinical analysis: NALTREXONE HYDROCHLORIDE versus NARCAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NALTREXONE HYDROCHLORIDE versus NARCAN.
NALTREXONE HYDROCHLORIDE vs NARCAN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Competitive antagonist at mu, kappa, and delta opioid receptors, with highest affinity for mu receptors. Also acts as an antagonist at the toll-like receptor 4 (TLR4).
Opioid receptor antagonist; binds competitively to mu, kappa, and delta opioid receptors, reversing opioid effects.
50 mg orally once daily for opioid dependence; 25 mg orally once daily for alcohol dependence, may increase to 50 mg after one week.
Initial dose: 0.4 mg to 2 mg IV, IM, or SC, repeated every 2 to 3 minutes as needed. For opioid-induced respiratory depression, may use 0.1 to 0.2 mg IV increments in patients with opioid dependence to avoid withdrawal.
None Documented
None Documented
Terminal elimination half-life: ~4 hours for naltrexone; its major active metabolite, 6-β-naltrexol, has a half-life of ~13 hours. The longer half-life of the metabolite contributes to sustained receptor blockade.
Approximately 1 hour in adults; context: shorter than most opioids (e.g., morphine 2-4 h), necessitating repeated doses for prolonged opioid effects.
Renal: primarily as unchanged drug (<2%) and metabolites (mainly 6-β-naltrexol, glucuronide conjugates); approximately 60% of dose excreted in urine (including metabolites) and about 30% in feces via biliary excretion.
Primarily hepatic metabolism (glucuronidation) followed by renal excretion of metabolites; <5% excreted unchanged in urine.
Category A/B
Category C
Opioid Antagonist
Opioid Antagonist