Comparative Pharmacology
Head-to-head clinical analysis: LORATADINE versus PROMETHAZINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: LORATADINE versus PROMETHAZINE.
LORATADINE vs PROMETHAZINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Loratadine is a long-acting tricyclic antihistamine with selective peripheral H1-receptor antagonist activity. It inhibits histamine-induced vasodilation and bronchoconstriction.
Promethazine is a phenothiazine derivative that acts as a potent histamine H1 receptor antagonist, thereby blocking the effects of histamine. It also has central anticholinergic, antiemetic, and sedative properties, likely mediated through antagonism at muscarinic, dopamine D2, and serotonin receptors in the brain.
10 mg orally once daily
12.5-25 mg IM or IV every 4-6 hours; also 25 mg PO or PR every 6-8 hours. Maximum 100 mg/day.
None Documented
None Documented
Loratadine: 8-14 hours (mean ~10 hours). Active metabolite descarboethoxyloratadine: 17-24 hours (mean ~20 hours). Clinically, duration supports once-daily dosing.
Clinical Note
moderateLoratadine + Fluticasone propionate
"The risk or severity of adverse effects can be increased when Loratadine is combined with Fluticasone propionate."
Clinical Note
moderateLoratadine + Teriflunomide
"The metabolism of Teriflunomide can be decreased when combined with Loratadine."
Clinical Note
moderateLoratadine + Haloperidol
"The metabolism of Haloperidol can be decreased when combined with Loratadine."
Clinical Note
moderatePromethazine + Risedronic acid
Terminal elimination half-life 9-16 hours; may be prolonged in hepatic impairment.
Approximately 40% excreted in urine as metabolites (primarily descarboethoxyloratadine) and 40% in feces as metabolites; <1% excreted unchanged.
Renal (70-80% as metabolites, <1% unchanged); biliary/fecal minor.
Category A/B
Category A/B
Antihistamine
Antihistamine / Antiemetic
"Promethazine can cause an increase in the absorption of Risedronic acid resulting in an increased serum concentration and potentially a worsening of adverse effects."