Comparative Pharmacology
Head-to-head clinical analysis: OPANA ER versus TALWIN 50.
Peer-Reviewed Evidence
Head-to-head clinical analysis: OPANA ER versus TALWIN 50.
OPANA ER vs TALWIN 50
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Opana ER (oxymorphone hydrochloride) is a full opioid agonist with relative selectivity for the mu-opioid receptor, although it can interact with other opioid receptors at higher doses. The principal therapeutic action is analgesia via activation of mu-opioid receptors in the central nervous system, leading to altered perception and response to pain.
Pentazocine is a mixed agonist-antagonist opioid analgesic with activity at kappa opioid receptors (agonist) and mu opioid receptors (partial agonist/antagonist). It also exhibits weak antagonistic activity at mu receptors, which reduces abuse liability but may precipitate withdrawal in opioid-dependent patients.
Initial: 5 mg orally every 12 hours; titrate by 5-10 mg every 12 hours every 3-7 days; maximum 40 mg every 12 hours.
50 mg orally every 3-4 hours as needed; maximum 600 mg per day.
None Documented
None Documented
Terminal elimination half-life: 11.1–13.8 hours; clinically relevant as steady-state achieved in 2–3 days
Terminal elimination half-life is 2-3 hours. In patients with hepatic impairment, half-life may extend to 5-8 hours; in renal impairment, minimal change, but active metabolite accumulation may occur.
Renal (primarily as glucuronide conjugates and unchanged drug): 85-90%; Fecal: <10%
Primarily renal (60-70% as unchanged drug and conjugates), with 20-30% biliary/fecal elimination. Approximately 5-10% excreted in feces via bile.
Category C
Category C
Opioid Analgesic
Opioid Analgesic