Comparative Pharmacology
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus CETIRIZINE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BENADRYL PRESERVATIVE FREE versus CETIRIZINE.
BENADRYL PRESERVATIVE FREE vs Cetirizine
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.
Cetirizine is a selective second-generation H1-receptor antagonist that inhibits histamine release from mast cells and basophils, thereby reducing allergic symptoms.
25-50 mg IV/IM every 4-6 hours as needed; maximum single dose 100 mg, maximum daily dose 400 mg.
10 mg orally once daily; 5 mg orally once daily for mild symptoms
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).
Clinical Note
moderateCetirizine + Fluticasone propionate
"The risk or severity of adverse effects can be increased when Cetirizine is combined with Fluticasone propionate."
Clinical Note
moderateLevocetirizine + Sulfisoxazole
"The metabolism of Sulfisoxazole can be decreased when combined with Levocetirizine."
Clinical Note
moderateLevocetirizine + Erythromycin
"The metabolism of Erythromycin can be decreased when combined with Levocetirizine."
Clinical Note
moderateLevocetirizine + Cyclosporine
Terminal elimination half-life is approximately 8.3 hours in healthy adults; extended to 20 hours in elderly and patients with renal impairment
Primarily renal (90% as metabolites and unchanged drug); ~1% excreted in feces via bile. Unchanged diphenhydramine accounts for <5% of urinary recovery.
Primarily renal (60% unchanged in urine); minor biliary/fecal (10%)
Category C
Category A/B
Antihistamine
Antihistamine
"The metabolism of Cyclosporine can be decreased when combined with Levocetirizine."