Comparative Pharmacology
Head-to-head clinical analysis: DESLORATADINE versus PROMETHAZINE W DEXTROMETHORPHAN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DESLORATADINE versus PROMETHAZINE W DEXTROMETHORPHAN.
DESLORATADINE vs PROMETHAZINE W/ DEXTROMETHORPHAN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Desloratadine is a long-acting tricyclic histamine antagonist selective for the H1 receptor, inhibiting histamine release from mast cells and basophils. It reduces allergic inflammation by decreasing cytokine and chemokine release.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist and antiemetic; dextromethorphan is a non-opioid antitussive that acts as an NMDA receptor antagonist and sigma-1 receptor agonist.
5 mg orally once daily.
5 mL (containing promethazine 6.25 mg and dextromethorphan 15 mg) orally every 4-6 hours as needed, not to exceed 30 mL (promethazine 37.5 mg, dextromethorphan 90 mg) per 24 hours.
None Documented
None Documented
Clinical Note
moderateDesloratadine + Venlafaxine
"The risk or severity of adverse effects can be increased when Desloratadine is combined with Venlafaxine."
Clinical Note
moderateDesloratadine + Nefazodone
"The risk or severity of adverse effects can be increased when Desloratadine is combined with Nefazodone."
Clinical Note
moderateDesloratadine + Stiripentol
"The risk or severity of adverse effects can be increased when Desloratadine is combined with Stiripentol."
Clinical Note
moderateTerminal half-life 27 hours (range 21–30 h) in healthy adults; supports once-daily dosing.
Promethazine: 9-16 h; dextromethorphan: 3-5 h (extensive metabolizers), 30-50 h (poor metabolizers). Clinical context: dosing interval typically 4-6 h for dextromethorphan; promethazine accumulates with repeated dosing.
Primarily renal (87% as metabolites, ~41% unchanged) and fecal (~9%). Metabolized to active 3-hydroxydesloratadine.
Renal: promethazine ~6% unchanged, dextromethorphan ~0.5% unchanged; metabolites primarily renal. Biliary/fecal: minor routes for both.
Category A/B
Category A/B
Antihistamine
Antihistamine / Antiemetic
Desloratadine + Fesoterodine
"The serum concentration of the active metabolites of Fesoterodine can be increased when Fesoterodine is used in combination with Desloratadine."