Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus ZYDONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus ZYDONE.
DARVON vs ZYDONE
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.
Hydrocodone is a mu-opioid receptor agonist; acetaminophen produces analgesia via central COX inhibition and activation of descending serotonergic pathways.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
Oral: 1 to 2 tablets every 4 to 6 hours as needed for pain. Each tablet contains hydrocodone bitartrate 5 mg and acetaminophen 500 mg (Zydone 5/500). Maximum acetaminophen dose: 4000 mg/day (8 tablets).
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Terminal elimination half-life of hydrocodone is 3.8-4.5 hours in healthy adults; prolonged in elderly or hepatic impairment (up to 6-8 hours). Clinical context: dosing interval typically every 4-6 hours, adjusted for renal/hepatic insufficiency.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Approximately 60% of hydrocodone and its metabolites are excreted renally as glucuronide conjugates; ~10% as norhydrocodone, hydromorphone, and other metabolites. Fecal excretion accounts for less than 5%. Total renal elimination: ~65-70%.
Category C
Category C
Opioid Analgesic
Opioid Analgesic