Comparative Pharmacology
Head-to-head clinical analysis: PHENERGAN VC versus PROMETHAZINE W CODEINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PHENERGAN VC versus PROMETHAZINE W CODEINE.
PHENERGAN VC vs PROMETHAZINE W/ CODEINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Phenergan VC is a combination of promethazine (a phenothiazine derivative with antihistaminic, sedative, antiemetic, and anticholinergic effects) and phenylephrine (a sympathomimetic amine that acts as a decongestant via alpha-1 adrenergic receptor agonism). Promethazine antagonizes H1 receptors, thereby suppressing allergic reactions and motion sickness. Phenylephrine causes vasoconstriction in the nasal mucosa, reducing congestion.
Codeine is a prodrug converted to morphine, a mu-opioid receptor agonist, which inhibits nociceptive transmission; promethazine is a phenothiazine derivative with H1-receptor antagonism, anticholinergic, and antiemetic effects.
10-20 mL orally every 4-6 hours as needed; each 5 mL contains 6.25 mg promethazine HCl and 5 mg phenylephrine HCl.
10 mL (1 mg codeine, 6.25 mg promethazine per 5 mL) orally every 4-6 hours as needed for cough. Maximum: 60 mL per day. Do not exceed 5 days.
None Documented
None Documented
9-16 hours; prolonged in hepatic impairment.
Promethazine: 10-19 hours (terminal). Codeine: 2.5-3.5 hours (terminal); prolonged in renal impairment.
Renal: 70-80% as metabolites; biliary/fecal: 20-30%.
Promethazine: renal (70% as metabolites, <1% unchanged), fecal (20-30%). Codeine: renal (90%, of which 5-10% unchanged, rest as metabolites), fecal (minor).
Category C
Category A/B
Antihistamine/Decongestant Combination
Antihistamine / Antiemetic