Comparative Pharmacology
Head-to-head clinical analysis: NALTREXONE versus NARCAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: NALTREXONE versus NARCAN.
NALTREXONE vs NARCAN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Naltrexone is a pure opioid antagonist that competitively binds to μ-opioid receptors, blocking the effects of endogenous and exogenous opioids. It also antagonizes κ- and δ-opioid receptors to a lesser extent.
Opioid receptor antagonist; binds competitively to mu, kappa, and delta opioid receptors, reversing opioid effects.
Oral: 50 mg once daily for opioid dependence; 25 mg initially for first dose to minimize adverse effects. Intramuscular: 380 mg every 4 weeks for alcohol dependence.
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
Clinical Note
moderateMethylnaltrexone + Fesoterodine
"The serum concentration of the active metabolites of Fesoterodine can be increased when Fesoterodine is used in combination with Methylnaltrexone."
Clinical Note
moderateNaltrexone + Methadone
"The therapeutic efficacy of Methadone can be decreased when used in combination with Naltrexone."
Clinical Note
moderateNaltrexone + Dabigatran etexilate
"The serum concentration of the active metabolites of Dabigatran etexilate can be increased when Dabigatran etexilate is used in combination with Naltrexone."
Clinical Note
moderateNaltrexone: 3.9–10.3 hours; active metabolite 6β-naltrexol: 12.9 hours. Context: Trough levels of 6β-naltrexol sustain receptor blockade for 24–48 h.
Approximately 1 hour in adults; context: shorter than most opioids (e.g., morphine 2-4 h), necessitating repeated doses for prolonged opioid effects.
Primarily renal (60% as metabolites, including 6β-naltrexol; <2% unchanged) and biliary/fecal (30%).
Primarily hepatic metabolism (glucuronidation) followed by renal excretion of metabolites; <5% excreted unchanged in urine.
Category A/B
Category C
Opioid Antagonist
Opioid Antagonist
Naltrexone + Sufentanil
"The therapeutic efficacy of Sufentanil can be decreased when used in combination with Naltrexone."