Comparative Pharmacology
Head-to-head clinical analysis: PROMETHAZINE W CODEINE versus TAVIST ALLERGY SINUS HEADACHE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETHAZINE W CODEINE versus TAVIST ALLERGY SINUS HEADACHE.
PROMETHAZINE W/ CODEINE vs TAVIST ALLERGY/SINUS/HEADACHE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
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.
TAVIST ALLERGY/SINUS/HEADACHE contains clemastine fumarate (first-generation antihistamine) that competitively antagonizes histamine at H1 receptors, and acetaminophen that inhibits cyclooxygenase (COX) enzymes in the CNS, reducing prostaglandin synthesis and fever; phenylpropanolamine is an alpha-adrenergic agonist that causes vasoconstriction of nasal mucosa.
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.
1 tablet (acetaminophen 500 mg, diphenhydramine 12.5 mg, phenylephrine 10 mg) orally every 4-6 hours as needed; maximum 4 tablets per day
None Documented
None Documented
Promethazine: 10-19 hours (terminal). Codeine: 2.5-3.5 hours (terminal); prolonged in renal impairment.
5-7 hours for clemastine; 12-15 hours for pseudoephedrine; acetaminophen half-life 2-3 hours. Context: Clemastine half-life supports twice-daily dosing; pseudoephedrine's longer half-life allows 6-8 hour dosing intervals
Promethazine: renal (70% as metabolites, <1% unchanged), fecal (20-30%). Codeine: renal (90%, of which 5-10% unchanged, rest as metabolites), fecal (minor).
Renal excretion of unchanged drug and metabolites accounts for 70-80%, with 15-25% fecal elimination; bilary excretion contributes to remaining
Category A/B
Category C
Antihistamine / Antiemetic
Antihistamine/Decongestant Combination