Comparative Pharmacology
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus LEVOCETIRIZINE DIHYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus LEVOCETIRIZINE DIHYDROCHLORIDE.
BENADRYL PRESERVATIVE FREE vs LEVOCETIRIZINE DIHYDROCHLORIDE
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.
Levocetirizine is a selective antagonist of peripheral histamine H1 receptors, blocking histamine-induced allergic responses by inhibiting H1 receptor activation in the gastrointestinal tract, blood vessels, and respiratory tract.
25-50 mg IV/IM every 4-6 hours as needed; maximum single dose 100 mg, maximum daily dose 400 mg.
5 mg orally once daily in the evening.
None Documented
None Documented
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: 7-11 hours in adults. Clinically, this supports once-daily dosing; may be prolonged in renal impairment (creatinine clearance <30 mL/min).
Primarily renal (90% as metabolites and unchanged drug); ~1% excreted in feces via bile. Unchanged diphenhydramine accounts for <5% of urinary recovery.
Renal: 85% as unchanged drug (70%) and metabolites (15%); fecal: 13%; biliary: minimal (<2%).
Category C
Category A/B
Antihistamine
Antihistamine