Comparative Pharmacology
Head-to-head clinical analysis: ATARAX versus DIPHENHYDRAMINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: ATARAX versus DIPHENHYDRAMINE.
ATARAX vs Diphenhydramine
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Hydroxyzine is a piperazine derivative with antihistaminic (H1-receptor antagonist) and anticholinergic properties; also exhibits sedative, anxiolytic, and antiemetic effects due to suppression of activity in subcortical areas of the CNS.
Inverse agonist at histamine H1 receptors, blocking histamine-mediated effects in blood vessels, respiratory smooth muscle, and GI tract; also anticholinergic by blocking muscarinic receptors and sedative via central H1 receptor antagonism.
25 mg orally 3-4 times daily; maximum 100 mg per day. Also available as 50 mg intramuscular injection every 4-6 hours.
25-50 mg orally or intramuscularly every 4-6 hours; maximum 300 mg/day. Intravenous administration: 10-50 mg slow IV push (max 25 mg/min).
None Documented
None Documented
Clinical Note
moderateDiphenhydramine + Deferasirox
"The serum concentration of Deferasirox can be increased when it is combined with Diphenhydramine."
Clinical Note
moderateDiphenhydramine + Fluticasone propionate
"The risk or severity of adverse effects can be increased when Diphenhydramine is combined with Fluticasone propionate."
Clinical Note
moderateDiphenhydramine + Tenofovir disoproxil
"The metabolism of Tenofovir disoproxil can be decreased when combined with Diphenhydramine."
Clinical Note
moderateTerminal elimination half-life is approximately 20-25 hours in healthy adults; may be prolonged in elderly, hepatic impairment, or renal insufficiency (up to 30-40 hours); steady-state achieved within 3-4 days.
Terminal elimination half-life 4-8 hours in adults; prolonged in hepatic impairment (up to 20 hours) and elderly.
Primarily hepatic metabolism via CYP3A4 and CYP2D6; renal excretion of metabolites accounts for approximately 70-80% of the dose, with less than 1% excreted unchanged; fecal excretion is about 10-15%.
Primarily renal (90-95% as metabolites, <5% unchanged). Minor biliary/fecal elimination (<5%).
Category C
Category C
Antihistamine
Antihistamine
Diphenhydramine + Sulfisoxazole
"The metabolism of Sulfisoxazole can be decreased when combined with Diphenhydramine."