Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus ONSOLIS.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus ONSOLIS.
DARVON-N vs ONSOLIS
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.
Onsolis (fentanyl buccal soluble film) is an opioid agonist that binds to mu-opioid receptors in the central nervous system, producing analgesia by increasing potassium conductance and inhibiting calcium channels, leading to reduced neurotransmitter release and hyperpolarization of neurons.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
Onsolis (fentanyl buccal soluble film) is indicated for breakthrough pain in opioid-tolerant patients. The initial dose is 200 mcg placed on the buccal mucosa; titrate to effective dose in 200 mcg increments across subsequent episodes. Maximum frequency: 4 doses per day. Allow at least 2 hours between doses.
None Documented
None Documented
Propoxyphene: 6-12 hours; norpropoxyphene: 30-36 hours. Accumulation of norpropoxyphene on repeated dosing increases risk of toxicity.
Terminal elimination half-life is approximately 3-5 hours in adults, providing sustained analgesic effect with multiple daily dosing.
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Primarily hepatic metabolism via glucuronidation, with approximately 70% of the dose excreted in urine as metabolites and 10-15% in feces as unchanged drug.
Category C
Category C
Opioid Analgesic
Opioid Analgesic