Comparative Pharmacology
Head-to-head clinical analysis: DIPHENHYDRAMINE HYDROCHLORIDE PRESERVATIVE FREE versus PBZ.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DIPHENHYDRAMINE HYDROCHLORIDE PRESERVATIVE FREE versus PBZ.
DIPHENHYDRAMINE HYDROCHLORIDE PRESERVATIVE FREE vs PBZ
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Competitive antagonist of histamine H1 receptors; centrally acting anticholinergic agent that inhibits acetylcholine muscarinic receptors.
PBZ (phenylbutazone) is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis. It also has uricosuric effects.
25 to 50 mg intravenously or intramuscularly every 4 to 6 hours as needed; maximum 400 mg per day.
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: 4-10 hours (mean ~8 hours); prolonged in hepatic impairment or elderly (up to 20 hours).
Terminal elimination half-life: 8-12 hours in adults; prolonged in renal impairment (up to 24 hours).
Primarily renal as inactive metabolites; ~60% of a dose appears in urine as metabolites, with <5% unchanged. Minor biliary/fecal elimination (<10%).
Renal excretion of unchanged drug (approximately 70-80%) with the remainder as metabolites. Biliary/fecal excretion accounts for <5%.
Category A/B
Category C
Antihistamine
Antihistamine