Comparative Pharmacology
Head-to-head clinical analysis: PROMETH HYDROCHLORIDE PHENYLEPHRINE HYDROCHLORIDE W CODEINE PHOSPHATE versus WESTADONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETH HYDROCHLORIDE PHENYLEPHRINE HYDROCHLORIDE W CODEINE PHOSPHATE versus WESTADONE.
PROMETH HYDROCHLORIDE,PHENYLEPHRINE HYDROCHLORIDE W/CODEINE PHOSPHATE vs WESTADONE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist, anticholinergic, and antiemetic; phenylephrine is an alpha-1 adrenergic receptor agonist causing vasoconstriction; codeine is an opioid agonist at mu-opioid receptors, producing analgesia and antitussive effects.
Mu-opioid receptor agonist; also acts as an NMDA receptor antagonist and inhibits serotonin and norepinephrine reuptake.
Promethazine 6.25 mg/phenylephrine 5 mg/codeine 10 mg per 5 mL oral solution: 5 mL every 4 hours as needed; max 30 mL/day.
Oral: 2.5-10 mg every 4-6 hours as needed for pain; maximum 40 mg per day.
None Documented
None Documented
Codeine: 2.5-3.5 hours (neonates: 4.5 hours); Promethazine: 9-16 hours (metabolites up to 24 hours); Phenylephrine: 2-3 hours (oral) or 30-60 minutes (IV).
Terminal elimination half-life: 15-60 hours (mean ~24 hours). Clinical context: Prolonged half-life supports once-daily dosing in opioid maintenance; accumulation occurs with repeated dosing due to long half-life.
Codeine: renal (10-30% unchanged, 40-70% as codeine-6-glucuronide, 5-15% as morphine and norcodeine conjugates); Promethazine: renal (70-80% as metabolites); Phenylephrine: renal (80-90% unchanged and as sulfate conjugates).
Primarily renal (40-50% as unchanged methadone and its metabolites, 15-20% as metadone-N-oxide), biliary/fecal (5-10%).
Category D/X
Category C
Opioid Agonist
Opioid Agonist