Comparative Pharmacology
Head-to-head clinical analysis: PROPOXYPHENE COMPOUND 65 versus ULTRACET.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROPOXYPHENE COMPOUND 65 versus ULTRACET.
PROPOXYPHENE COMPOUND 65 vs ULTRACET
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Propoxyphene is an opioid analgesic that binds to mu-opioid receptors in the central nervous system, resulting in inhibition of ascending pain pathways and alteration of pain perception. Acetaminophen component inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis.
ULTRACET is a combination of tramadol (a centrally acting opioid agonist) and acetaminophen (a centrally acting analgesic with antipyretic effects). Tramadol binds to mu-opioid receptors and inhibits norepinephrine and serotonin reuptake. Acetaminophen's mechanism is not fully understood but involves inhibition of cyclooxygenase (COX) enzymes in the central nervous system.
Adults: 1 capsule (65 mg propoxyphene HCl + 650 mg acetaminophen) orally every 4 hours as needed; maximum 6 capsules per day.
1-2 tablets (37.5 mg tramadol/325 mg acetaminophen per tablet) orally every 4-6 hours as needed for pain, not to exceed 8 tablets per day.
None Documented
None Documented
The terminal elimination half-life of propoxyphene is approximately 8-24 hours (mean 12 hours) in healthy adults. The half-life of its active metabolite, norpropoxyphene, is 30-36 hours, leading to prolonged effects and potential accumulation with repeated dosing, especially in renal impairment.
Tramadol: 5.1 ± 0.9 hours (range 4-6 hours) for the parent drug; the active M1 metabolite has a half-life of 6.7 ± 1.7 hours. In hepatic impairment, tramadol half-life increases ~2-3 fold. Acetaminophen: 2-3 hours (range 1.25-3 hours); prolonged in overdose.
Renal excretion of propoxyphene and its metabolites accounts for approximately 70-90% of an administered dose, with less than 5% excreted as unchanged drug. The remainder is eliminated via bile and feces. Minor amounts are excreted in breast milk.
Tramadol and its metabolites are primarily excreted via the kidneys (approximately 90% of the dose), with about 30% excreted as unchanged drug and 60% as metabolites. Approximately 10% is excreted in feces. Acetaminophen is primarily conjugated in the liver and excreted renally as glucuronide (60-80%) and sulfate (20-30%) conjugates, with about 5% excreted unchanged.
Category C
Category C
Opioid Analgesic Combination
Opioid Analgesic Combination