Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus XTAMPZA ER.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus XTAMPZA ER.
DARVON vs XTAMPZA ER
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.
Oxycodone is a full mu-opioid receptor agonist, producing analgesia, euphoria, and sedation. Xtampza ER utilizes DETERx technology to provide extended-release properties and resist tampering.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
Initial: 9 mg orally every 12 hours with food; titrate by 9 mg every 3-7 days as needed; maximum dose: 36 mg every 12 hours.
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
3-4 hours for immediate-release morphine; 8-12 hours for extended-release formulation (XTAMPZA ER), allowing twice-daily dosing
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Primarily renal (70-90% as morphine-3-glucuronide, morphine-6-glucuronide, and free morphine); biliary/fecal (10-20%)
Category C
Category C
Opioid Analgesic
Opioid Analgesic