Comparative Pharmacology
Head-to-head clinical analysis: LORATADINE REDIDOSE versus PROMETHAZINE W CODEINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LORATADINE REDIDOSE versus PROMETHAZINE W CODEINE.
LORATADINE REDIDOSE vs PROMETHAZINE W/ CODEINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Selective peripheral H1 receptor antagonist; inhibits histamine release from mast cells.
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 mg orally once daily
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
Terminal elimination half-life is 8–14 hours (mean ~12 hours) for desloratadine (active metabolite); parent loratadine half-life ~3–20 hours (mean ~8 hours). Clinically, once-daily dosing maintains steady state in 5–7 days.
Promethazine: 10-19 hours (terminal). Codeine: 2.5-3.5 hours (terminal); prolonged in renal impairment.
Renal (approximately 40% as metabolites), biliary/fecal (approximately 60% as metabolites). Less than 1% excreted unchanged in urine.
Promethazine: renal (70% as metabolites, <1% unchanged), fecal (20-30%). Codeine: renal (90%, of which 5-10% unchanged, rest as metabolites), fecal (minor).
Category A/B
Category A/B
Antihistamine
Antihistamine / Antiemetic