Comparative Pharmacology
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus BENYLIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus BENYLIN.
BENADRYL PRESERVATIVE FREE vs BENYLIN
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.
BENYLIN (diphenhydramine) is a first-generation antihistamine that competitively antagonizes histamine at H1 receptors, thereby alleviating allergic symptoms. It also crosses the blood-brain barrier and acts as a central nervous system depressant via inhibition of histamine and acetylcholine, producing sedative, antiemetic, and antitussive effects.
25-50 mg IV/IM every 4-6 hours as needed; maximum single dose 100 mg, maximum daily dose 400 mg.
Oral: 10-20 mL (25-50 mg diphenhydramine) every 4-6 hours; maximum 100 mg per day.
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: 4-6 hours in adults; extended to 10-12 hours in hepatic impairment, increasing risk of accumulation.
Primarily renal (90% as metabolites and unchanged drug); ~1% excreted in feces via bile. Unchanged diphenhydramine accounts for <5% of urinary recovery.
Renal: ~80% as unchanged drug and glucuronide conjugates; fecal/biliary: ~20%.
Category C
Category C
Antihistamine
Antihistamine