Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus VICODIN ES.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus VICODIN ES.
DARVON vs VICODIN ES
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 inhibits cyclooxygenase (COX) and modulates 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 tablet (7.5 mg hydrocodone/300 mg acetaminophen) every 4-6 hours as needed for pain; maximum 6 tablets per day due to acetaminophen limit.
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Hydrocodone: terminal half-life approximately 3.3-4.5 hours in adults, extended in hepatic or renal impairment. Acetaminophen: terminal half-life about 2-3 hours.
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Hydrocodone: primarily renal (urine) as unchanged drug and metabolites (O-demethylation and 6-keto-reduction products); ~26% excreted unchanged. Acetaminophen: renal (urine), ~85% as glucuronide and sulfate conjugates, ~2% unchanged.
Category C
Category C
Opioid Analgesic
Opioid Analgesic