Comparative Pharmacology
Head-to-head clinical analysis: DARVOCET N 100 versus OPANA ER.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVOCET N 100 versus OPANA ER.
DARVOCET-N 100 vs OPANA ER
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a weak opioid agonist that binds to mu-opioid receptors in the CNS, altering pain perception. Acetaminophen inhibits cyclooxygenase (COX) enzymes centrally, reducing prostaglandin synthesis and providing analgesia.
Opana ER (oxymorphone hydrochloride) is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can interact with other opioid receptors at higher doses. The principal therapeutic action is analgesia via activation of mu-opioid receptors in the central nervous system, leading to altered perception and response to pain.
Darvocet-N 100 contains propoxyphene napsylate 100 mg and acetaminophen 650 mg. For moderate to moderately severe pain, the typical adult dose is 1 tablet orally every 4 hours as needed. Maximum: 6 tablets per day (600 mg propoxyphene napsylate, 3900 mg acetaminophen).
Initial: 5 mg orally every 12 hours; titrate by 5-10 mg every 12 hours every 3-7 days; maximum 40 mg every 12 hours.
None Documented
None Documented
Propoxyphene: 6-12 hours (prolonged in elderly and hepatic impairment); norpropoxyphene metabolite: 30-36 hours. Acetaminophen: 1.5-3 hours.
Terminal elimination half-life: 11.1–13.8 hours; clinically relevant as steady-state achieved in 2–3 days
Propoxyphene: primarily hepatic metabolism to norpropoxyphene, renal excretion of metabolites (20-25% unchanged propoxyphene). Acetaminophen: renal excretion of glucuronide and sulfate conjugates (90-95% total), 2-4% unchanged.
Renal (primarily as glucuronide conjugates and unchanged drug): 85-90%; Fecal: <10%
Category C
Category C
Opioid Analgesic
Opioid Analgesic