Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus OXTELLAR XR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus OXTELLAR XR.
DARVON vs OXTELLAR XR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a mu-opioid receptor agonist that inhibits ascending pain pathways by binding to opioid receptors in the CNS, altering pain perception. It also has weak local anesthetic effects.
Oxtellar XR (oxcarbazepine) is a prodrug that is converted to its active metabolite, MHD (10,11-dihydro-10-hydroxy-carbazepine). The exact mechanism of action is unknown, but it is thought to stabilize neuronal membranes by blocking voltage-gated sodium channels, thereby inhibiting repetitive neuronal firing and reducing the propagation of synaptic impulses.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
Oxcarbazepine extended-release (OXTELLAR XR) adult dosing: 600 mg orally twice daily; initial dose 300 mg twice daily, titrate by 300 mg/day increments weekly; maximum 2400 mg/day.
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Terminal half-life approximately 20-30 hours in adults; after multiple doses, effective half-life is about 24 hours, allowing once-daily dosing. Steady state reached in 4-5 days.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Primarily renal (70-80% as unchanged drug and metabolites) and fecal (20-30% via biliary excretion).
Category C
Category C
Opioid Analgesic
Opioid Analgesic