Comparative Pharmacology
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus HYDROXYZINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus HYDROXYZINE.
BENADRYL PRESERVATIVE FREE vs HYDROXYZINE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Diphenhydramine competitively antagonizes histamine at H1-receptors on effector cells, leading to relief of allergic symptoms. It also possesses anticholinergic, antiemetic, sedative, and local anesthetic effects.
Hydroxyzine is a first-generation antihistamine that acts as a competitive antagonist at histamine H1 receptors in the gastrointestinal tract, blood vessels, and respiratory tract. It also exhibits sedative, anxiolytic, and antiemetic properties, possibly through central nervous system depression and anticholinergic effects.
25-50 mg IV/IM every 4-6 hours as needed; maximum single dose 100 mg, maximum daily dose 400 mg.
25-100 mg orally 3-4 times daily; 50-100 mg IM every 4-6 hours as needed. Maximum oral dose: 600 mg/day in divided doses.
None Documented
None Documented
Clinical Note
moderateHydroxyzine + Venlafaxine
"The risk or severity of adverse effects can be increased when Hydroxyzine is combined with Venlafaxine."
Clinical Note
moderateHydroxyzine + Nefazodone
"The risk or severity of adverse effects can be increased when Hydroxyzine is combined with Nefazodone."
Clinical Note
moderateHydroxyzine + Mifepristone
"Hydroxyzine may increase the QTc-prolonging activities of Mifepristone."
Clinical Note
moderateHydroxyzine + Fesoterodine
Terminal elimination half-life: 4-8 hours (mean ~5 hours). Prolonged in hepatic impairment (up to 2-fold) and elderly (7-12 hours).
Terminal elimination half-life: 14-25 hours (mean ~20 h). In elderly or hepatic impairment, may be prolonged; antihistamine effect persists beyond half-life due to active metabolite.
Primarily renal (90% as metabolites and unchanged drug); ~1% excreted in feces via bile. Unchanged diphenhydramine accounts for <5% of urinary recovery.
Renal: approximately 70% as metabolites, less than 1% unchanged. Fecal/biliary: minor. Cetirizine (active metabolite) also renally eliminated.
Category C
Category A/B
Antihistamine
Antihistamine
"The serum concentration of the active metabolites of Fesoterodine can be increased when Fesoterodine is used in combination with Hydroxyzine."