Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus VICODIN HP.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus VICODIN HP.
DARVON vs VICODIN HP
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 that inhibits ascending pain pathways; acetaminophen inhibits cyclooxygenase and has antipyretic effects.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
One tablet (hydrocodone bitartrate 10 mg/acetaminophen 660 mg) orally every 4-6 hours as needed for pain; maximum 6 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.
Hydrocodone: 3.8-5.5 hours (mean 4.5 h). Acetaminophen: 2-3 hours. Clinical context: dosing interval every 4-6 hours for acute pain.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Primarily renal: hydrocodone is eliminated as conjugated metabolites (glucuronides) ~80%; unchanged drug ~5%. Biliary/fecal: minor, <10%.
Category C
Category C
Opioid Analgesic
Opioid Analgesic