Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus XARTEMIS XR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus XARTEMIS XR.
DARVON vs XARTEMIS 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.
XARTEMIS XR is a combination of oxycodone (a full mu-opioid receptor agonist) and acetaminophen (a centrally acting analgesic with antipyretic properties via cyclooxygenase inhibition).
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
1 tablet (oxycodone 7.5 mg / acetaminophen 325 mg) orally every 12 hours; maximum 2 tablets per day.
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Oxycodone: 5.3-6.6 hours (immediate-release), extended-release formulation shows prolonged absorption with apparent half-life ~7.2-9.6 hours; naloxone: 2-3 hours.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Renal: oxycodone and metabolites ~8.8% free oxycodone, ~8.8% noroxycodone, ~33% conjugated metabolites; naloxone: extensive hepatic metabolism, <1% excreted unchanged in urine. Fecal: naloxone metabolites ~17%.
Category C
Category C
Opioid Analgesic
Opioid Analgesic