Comparative Pharmacology
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus PBZ.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus PBZ.
BENADRYL PRESERVATIVE FREE vs PBZ
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.
PBZ (phenylbutazone) is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis. It also has uricosuric effects.
25-50 mg IV/IM every 4-6 hours as needed; maximum single dose 100 mg, maximum daily dose 400 mg.
25-50 mg orally every 4-6 hours as needed; not to exceed 300 mg/day. For severe allergies: 25 mg intramuscularly or intravenously every 4-6 hours.
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: 8-12 hours in adults; prolonged in renal impairment (up to 24 hours).
Primarily renal (90% as metabolites and unchanged drug); ~1% excreted in feces via bile. Unchanged diphenhydramine accounts for <5% of urinary recovery.
Renal excretion of unchanged drug (approximately 70-80%) with the remainder as metabolites. Biliary/fecal excretion accounts for <5%.
Category C
Category C
Antihistamine
Antihistamine