Comparative Pharmacology
Head-to-head clinical analysis: DIPHEN versus HISTAFED.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DIPHEN versus HISTAFED.
DIPHEN vs HISTAFED
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Diphenhydramine is a first-generation antihistamine that competitively antagonizes histamine at H1 receptors. It also exhibits anticholinergic, sedative, antiemetic, and local anesthetic effects.
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.
50 mg IV/IM every 4 hours as needed for nausea/vomiting; 25-50 mg PO every 4-6 hours as needed for nausea/vomiting or motion sickness; 25 mg PO 3-4 times daily for vertigo; 15.6-25 mg IM/IV for antiemetic in surgery; maximum 300 mg/day.
60 mg orally every 4 to 6 hours as needed; maximum 360 mg per day.
None Documented
None Documented
Clinical Note
moderateDiphenoxylate + Torasemide
"The risk or severity of adverse effects can be increased when Diphenoxylate is combined with Torasemide."
Clinical Note
moderateDiphenoxylate + Etacrynic acid
"The risk or severity of adverse effects can be increased when Diphenoxylate is combined with Etacrynic acid."
Clinical Note
moderateDiphenoxylate + Furosemide
"The risk or severity of adverse effects can be increased when Diphenoxylate is combined with Furosemide."
Clinical Note
moderateTerminal elimination half-life is 22–72 hours (mean 30–40 hours); increases with hepatic disease or enzyme inhibitors.
3-4 hours for pseudoephedrine component; shorter in children (2-3 h), prolonged in renal impairment
Primarily hepatic metabolism; renal excretion of inactive metabolites accounts for ~70% of eliminated drug; biliary/fecal excretion accounts for ~30%.
Renal (approximately 65% as unchanged drug and metabolites), biliary/fecal (35%)
Category C
Category C
Antihistamine
Antihistamine/Decongestant Combination
Diphenoxylate + Bumetanide
"The risk or severity of adverse effects can be increased when Diphenoxylate is combined with Bumetanide."