Comparative Pharmacology
Head-to-head clinical analysis: DARVON versus ULTRAM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON versus ULTRAM.
DARVON vs ULTRAM
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.
Tramadol is a centrally acting synthetic opioid analgesic that binds to μ-opioid receptors and inhibits norepinephrine and serotonin reuptake.
Propoxyphene hydrochloride (Darvon) for moderate to severe pain: 65 mg orally every 4 hours as needed; maximum 390 mg/day.
50-100 mg orally every 4-6 hours as needed for pain; maximum 400 mg/day (for extended-release: 100 mg once daily, titrated up to 300 mg once daily).
None Documented
None Documented
6-12 hours (parent drug); norpropoxyphene half-life 30-36 hours, accumulates with repeated dosing, increasing risk of toxicity.
Tramadol: ~6 hours; M1 metabolite (O-desmethyltramadol): ~7 hours; prolonged in renal/hepatic impairment
Primarily hepatic metabolism to norpropoxyphene, then renal excretion of metabolites; <20% excreted unchanged in urine; minor biliary/fecal elimination.
Renal: ~90% (tramadol and metabolites; conjugated metabolites are major), Fecal: ~10%
Category C
Category C
Opioid Analgesic
Opioid Analgesic