Comparative Pharmacology
Head-to-head clinical analysis: AMBENYL versus VICKS FORMULA 44.
Peer-Reviewed Evidence
Head-to-head clinical analysis: AMBENYL versus VICKS FORMULA 44.
AMBENYL vs VICKS FORMULA 44
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
AMBENYL is a combination product containing codeine (opioid agonist) and bromodiphenhydramine (antihistamine). Codeine binds to mu-opioid receptors in the CNS, inhibiting ascending pain pathways and altering pain perception; bromodiphenhydramine antagonizes histamine H1 receptors, producing antitussive and sedative effects.
VICKS FORMULA 44 contains dextromethorphan (NMDA receptor antagonist and sigma-1 receptor agonist; suppresses cough by acting on the medullary cough center) and doxylamine (first-generation antihistamine; H1-receptor antagonist; anticholinergic and sedative effects).
Each 5 mL contains codeine phosphate 10 mg and diphenhydramine hydrochloride 12.5 mg. Adults: 10 mL (2 teaspoonfuls) orally every 4-6 hours as needed; maximum 40 mL per day.
VICKS FORMULA 44 is a combination product containing dextromethorphan (cough suppressant) and doxylamine (antihistamine). The typical adult dose is 30 mg dextromethorphan/6.25 mg doxylamine (15 mL) orally every 6 hours as needed for cough and cold symptoms, not to exceed 4 doses per 24 hours.
None Documented
None Documented
Codeine: 2.5-3.5 h (terminal) with CYP2D6 poor metabolizers up to 6 h. Guaifenesin: 1-2 h.
Dextromethorphan: 3-6 hours (extensive metabolizers), up to 24 hours (poor metabolizers); doxylamine: 10-12 hours. Clinically, half-life may be prolonged in elderly, hepatic impairment, or CYP2D6 poor metabolizers.
Renal: 60% unchanged codeine, 20% codeine-6-glucuronide; biliary/fecal: 20% as metabolites. Guaifenesin: renal 95% as unchanged drug and metabolites.
Renal excretion of unchanged drug and metabolites (dextromethorphan and doxylamine): dextromethorphan is extensively metabolized; <10% excreted unchanged. Doxylamine: ~60% excreted renally as unchanged and metabolites.
Category C
Category C
Antitussive/Antihistamine Combination
Antitussive