Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus EMBEDA.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus EMBEDA.
DARVON-N vs EMBEDA
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a weak mu-opioid receptor agonist that produces analgesia by binding to opioid receptors in the central nervous system, altering the perception of and response to pain. Its metabolite norpropoxyphene has local anesthetic and sodium channel blocking effects, which may contribute to cardiac toxicity.
EMBEDA is a combination of morphine sulfate, a full opioid agonist, and naltrexone hydrochloride, an opioid antagonist. Morphine binds to mu-opioid receptors in the CNS, altering pain perception and response. Naltrexone is sequestered in the core and is released if the pellets are crushed or chewed, potentially precipitating withdrawal or blockade of morphine effects.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
1 to 2 capsules orally every 12 hours, titrated to pain relief. Maximum daily dose: 100 mg naltrexone (equivalent to 100 mg morphine). Capsules must be swallowed whole.
None Documented
None Documented
Propoxyphene: 6-12 hours; norpropoxyphene: 30-36 hours. Accumulation of norpropoxyphene on repeated dosing increases risk of toxicity.
Morphine: 2-4 hours; naltrexone: 4-13 hours (active metabolite 6β-naltrexol: 12-18 hours). Clinically, morphine's half-life is prolonged in hepatic or renal impairment.
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Renal: ~60% (morphine), ~20% (naltrexone, in urine as unchanged drug and metabolites); biliary/fecal: ~10% (morphine-3-glucuronide and other metabolites).
Category C
Category C
Opioid Analgesic
Opioid Analgesic