Comparative Pharmacology
Head-to-head clinical analysis: BENADRYL versus PROMETHAZINE HYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BENADRYL versus PROMETHAZINE HYDROCHLORIDE.
BENADRYL vs PROMETHAZINE HYDROCHLORIDE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Antihistamine; inverse agonist at histamine H1 receptors, blocking histamine-induced vasodilation, increased capillary permeability, and bronchoconstriction; also anticholinergic and sedative.
Promethazine is a phenothiazine derivative that acts as a histamine H1 receptor antagonist, blocking the effects of histamine at H1 receptors. It also has anticholinergic, antiemetic, sedative, and antidopaminergic properties.
25-50 mg orally every 4-6 hours as needed; maximum 300 mg per day. Alternatively, 10-50 mg intramuscularly or intravenously once, maximum 100 mg per dose (IV route preferred).
25-50 mg intramuscular or intravenous injection every 4-6 hours as needed; also 12.5-25 mg orally every 4-6 hours.
None Documented
None Documented
Terminal elimination half-life 4-8 hours; prolonged in hepatic impairment (up to 20 hours).
Terminal elimination half-life is 10-19 hours in adults; prolonged in hepatic impairment (up to 30+ hours) and in elderly.
Renal (90% as metabolites, <5% unchanged); minimal biliary/fecal.
Primarily hepatic metabolism; renal excretion of metabolites accounts for <1% of unchanged drug; biliary/fecal excretion of metabolites ~70-80%.
Category C
Category A/B
Antihistamine
Antihistamine / Antiemetic