Comparative Pharmacology
Head-to-head clinical analysis: DARVON N versus STADOL PRESERVATIVE FREE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DARVON N versus STADOL PRESERVATIVE FREE.
DARVON-N vs STADOL PRESERVATIVE FREE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is a weak mu-opioid receptor agonist that produces analgesia by binding to opioid receptors in the central nervous system, altering the perception of and response to pain. Its metabolite norpropoxyphene has local anesthetic and sodium channel blocking effects, which may contribute to cardiac toxicity.
Butorphanol is a synthetic agonist-antagonist opioid analgesic that exerts its effects primarily through binding to kappa-opioid receptors and, to a lesser extent, mu-opioid receptors, producing analgesia and sedation. It also has partial antagonist activity at mu receptors.
100 mg orally every 4 hours as needed for pain; maximum 600 mg per day.
0.5–2 mg intravenously or intramuscularly every 3–4 hours as needed for pain. Alternatively, 1–2 mg as a single dose, may repeat in 30–60 minutes if needed.
None Documented
None Documented
Propoxyphene: 6-12 hours; norpropoxyphene: 30-36 hours. Accumulation of norpropoxyphene on repeated dosing increases risk of toxicity.
Terminal elimination half-life is 2.5–3.3 hours in adults; prolonged to 4–6 hours in elderly or hepatic impairment.
Primarily renal (approximately 70% as unchanged drug and glucuronide conjugates); minor biliary/fecal elimination (25-30%).
Primarily hepatic metabolism (glucuronidation) to inactive metabolites; renal excretion accounts for <5% unchanged drug. Approximately 70% of dose excreted in urine as metabolites, 20% in feces.
Category C
Category C
Opioid Analgesic
Opioid Analgesic