Comparative Pharmacology
Head-to-head clinical analysis: LORATADINE REDIDOSE versus PROMETHAZINE DM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LORATADINE REDIDOSE versus PROMETHAZINE DM.
LORATADINE REDIDOSE vs PROMETHAZINE DM
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.
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 mg orally once daily
2 teaspoonfuls (10 mL) orally every 4-6 hours, not to exceed 8 teaspoonfuls (40 mL) per 24 hours.
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.
16-19 hours (terminal); note: effect may last longer due to active metabolites and tissue binding
Renal (approximately 40% as metabolites), biliary/fecal (approximately 60% as metabolites). Less than 1% excreted unchanged in urine.
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal (20-30%)
Category A/B
Category A/B
Antihistamine
Antihistamine / Antiemetic