Comparative Pharmacology
Head-to-head clinical analysis: ABSTRAL versus DARVON N.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ABSTRAL versus DARVON N.
ABSTRAL vs DARVON-N
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Fentanyl is a potent mu-opioid receptor agonist, producing analgesia and sedation by activating G-protein coupled opioid receptors in the central nervous system.
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.
For breakthrough pain in opioid-tolerant patients: initial dose 100 mcg sublingual tablet, titrate across strengths (100, 200, 300, 400, 600, 800 mcg) as needed; maximum 2 doses per episode, minimum 2 hours between episodes.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
None Documented
None Documented
Terminal elimination half-life: 6-10 hours (mean 8 hours); prolonged in elderly and hepatic impairment
Propoxyphene: 6-12 hours; norpropoxyphene: 30-36 hours. Accumulation of norpropoxyphene on repeated dosing increases risk of toxicity.
Renal: ~70% as metabolites (primarily fentanyl conjugates and norfentanyl), ~10% unchanged; Fecal: ~9%; Biliary: minimal
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Category C
Category C
Opioid Analgesic
Opioid Analgesic