Comparative Pharmacology
Head-to-head clinical analysis: PHENAPHEN W CODEINE NO 4 versus QDOLO.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PHENAPHEN W CODEINE NO 4 versus QDOLO.
PHENAPHEN W/ CODEINE NO. 4 vs QDOLO
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Phenaphen w/ Codeine No. 4 contains acetaminophen and codeine. Acetaminophen inhibits prostaglandin synthesis in the CNS, reducing pain and fever. Codeine, an opioid prodrug, is converted to morphine via CYP2D6 and binds to mu-opioid receptors, inhibiting ascending pain pathways.
Tramadol is a centrally acting synthetic opioid analgesic. It binds to μ-opioid receptors and inhibits norepinephrine and serotonin reuptake.
1-2 tablets (300-600 mg acetaminophen / 30-60 mg codeine phosphate) orally every 4 hours as needed for pain; maximum 12 tablets per day.
Oral: 50-100 mg every 4-6 hours as needed for pain; maximum 400 mg per day. Immediate-release tablets only. Extended-release formulations require different dosing and are not interchangeable.
None Documented
None Documented
Codeine: 2.5-3.5 h; morphine: 2-4 h; clinically, analgesia correlates with morphine levels
Terminal elimination half-life approximately 2-4 hours in adults; prolonged to 4-6 hours in elderly and up to 12-16 hours in severe renal impairment (CrCl <30 mL/min)
Renal: 90-100% as codeine and metabolites (codeine: 5-15%, morphine: 10%, norcodeine: 10%, morphine-3-glucuronide: 50%, morphine-6-glucuronide: <5%); biliary/fecal: minimal (<5%)
Renal 90% (60% unchanged, 30% as glucuronide conjugate), fecal 10%
Category D/X
Category C
Opioid Agonist
Opioid Agonist