Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus VICODIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus VICODIN.
DARVON vs VICODIN
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.
VICODIN (hydrocodone/acetaminophen) is a combination opioid agonist and analgesic. Hydrocodone acts on mu-opioid receptors in the CNS to alter pain perception and response; acetaminophen inhibits cyclooxygenase (COX) activity, likely in the CNS, reducing prostaglandin synthesis and providing antipyretic effects.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
1-2 tablets (hydrocodone 5-10 mg and acetaminophen 300-325 mg) orally every 4-6 hours as needed for pain; maximum daily acetaminophen dose 4 g.
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Hydrocodone: 3.8-6.4 hours (terminal); Acetaminophen: 2-3 hours (terminal). Clinically, steady-state achieved in 1-2 days.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Hydrocodone: primarily renal (~60% as metabolites, 12% unchanged); minor biliary. Acetaminophen: renal (90-100% as metabolites, 2-4% unchanged).
Category C
Category C
Opioid Analgesic
Opioid Analgesic