Comparative Pharmacology
Head-to-head clinical analysis: PROMETHAZINE WITH CODEINE versus TAVIST 1.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROMETHAZINE WITH CODEINE versus TAVIST 1.
PROMETHAZINE WITH CODEINE vs TAVIST-1
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Promethazine is a phenothiazine derivative that antagonizes histamine at H1 receptors, acting as a sedative and antiemetic. Codeine is an opioid agonist at mu-opioid receptors, producing analgesia and antitussive effects via central nervous system depression.
TAVIST-1 (clemastine fumarate) is a first-generation antihistamine that acts as a competitive antagonist at histamine H1 receptors, thereby preventing histamine-mediated effects such as vasodilation, increased capillary permeability, and bronchoconstriction. It also exhibits anticholinergic and sedative properties.
10-20 mg promethazine and 10-20 mg codeine (based on phosphate) orally every 4-6 hours as needed for cough; maximum daily codeine dose 120 mg.
1.34 mg orally twice daily; maximum 8.04 mg/day.
None Documented
None Documented
Promethazine: 9-16 hours (mean 12 hours), clinically significant for sedation duration. Codeine: 2.5-4 hours (mean 3 hours), with active metabolite morphine 2-3 hours.
Terminal half-life 12–15 hours; clinical dosing interval every 12 hours.
Promethazine: renal 70% as metabolites and unchanged drug, biliary/fecal 20-30%. Codeine: renal 90% (5-15% unchanged, rest as morphine and conjugates), fecal <10%.
Primarily renal: ~60% unchanged; biliary/fecal: ~30% as metabolites; minor via feces.
Category A/B
Category C
Antihistamine / Antiemetic
Antihistamine