Comparative Pharmacology
Head-to-head clinical analysis: PHENERGAN VC versus PROMETHAZINE DM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PHENERGAN VC versus PROMETHAZINE DM.
PHENERGAN VC vs PROMETHAZINE DM
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.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist, antiemetic via blockade of dopamine D2 receptors in the chemoreceptor trigger zone, and sedative via central anticholinergic effects. Dextromethorphan is an NMDA receptor antagonist and sigma-1 receptor agonist, suppressing cough by central action on the cough center.
10-20 mL orally every 4-6 hours as needed; each 5 mL contains 6.25 mg promethazine HCl and 5 mg phenylephrine HCl.
2 teaspoonfuls (10 mL) orally every 4-6 hours, not to exceed 8 teaspoonfuls (40 mL) per 24 hours.
None Documented
None Documented
9-16 hours; prolonged in hepatic impairment.
16-19 hours (terminal); note: effect may last longer due to active metabolites and tissue binding
Renal: 70-80% as metabolites; biliary/fecal: 20-30%.
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal (20-30%)
Category C
Category A/B
Antihistamine/Decongestant Combination
Antihistamine / Antiemetic