Comparative Pharmacology
Head-to-head clinical analysis: DIPHEN versus OLOPATADINE HYDROCHLORIDE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: DIPHEN versus OLOPATADINE HYDROCHLORIDE.
DIPHEN vs OLOPATADINE HYDROCHLORIDE
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.
Olopatadine hydrochloride is a selective histamine H1 receptor antagonist and mast cell stabilizer. It inhibits histamine release from mast cells and prevents histamine-induced effects such as increased vascular permeability and pruritus.
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.
One drop of 0.1% or 0.2% ophthalmic solution in each affected eye twice daily (every 6-8 hours) for 0.1%; once daily for 0.2%.
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.
Terminal elimination half-life of 8–12 hours in healthy adults; prolonged in hepatic impairment (up to 18 hours)
Primarily hepatic metabolism; renal excretion of inactive metabolites accounts for ~70% of eliminated drug; biliary/fecal excretion accounts for ~30%.
Primarily renal excretion (60-70% unchanged), with minor biliary/fecal elimination (~30% as metabolites)
Category C
Category A/B
Antihistamine
Antihistamine / Mast Cell Stabilizer
Diphenoxylate + Bumetanide
"The risk or severity of adverse effects can be increased when Diphenoxylate is combined with Bumetanide."