Comparative Pharmacology
Head-to-head clinical analysis: HISTAFED versus ISOCLOR.
Peer-Reviewed Evidence
Head-to-head clinical analysis: HISTAFED versus ISOCLOR.
HISTAFED vs ISOCLOR
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
HISTAFED is a combination of pseudoephedrine, a sympathomimetic amine that acts as a decongestant by stimulating alpha-adrenergic receptors in the nasal mucosa causing vasoconstriction, and triprolidine, a first-generation antihistamine that competes with histamine for H1-receptor sites on effector cells in the gastrointestinal tract, blood vessels, and respiratory tract, thereby preventing histamine-mediated effects.
Chlorpheniramine is an antihistamine (H1-receptor antagonist) that blocks the action of histamine, reducing allergy symptoms. Pseudoephedrine is a sympathomimetic amine that acts as a decongestant by stimulating alpha-adrenergic receptors, causing vasoconstriction in the nasal mucosa.
60 mg orally every 4 to 6 hours as needed; maximum 360 mg per day.
Oral: 1 tablet (chlorpheniramine 4 mg / pseudoephedrine 60 mg) every 4-6 hours, not to exceed 4 tablets per 24 hours.
None Documented
None Documented
3-4 hours for pseudoephedrine component; shorter in children (2-3 h), prolonged in renal impairment
Approximately 2-4 hours in patients with normal renal function; prolonged to 8-12 hours in renal impairment (CrCl <30 mL/min).
Renal (approximately 65% as unchanged drug and metabolites), biliary/fecal (35%)
Primarily renal; approximately 60-70% of a dose excreted unchanged in urine within 24 hours. Biliary/fecal excretion accounts for <10%.
Category C
Category C
Antihistamine/Decongestant Combination
Antihistamine/Decongestant Combination