Comparative Pharmacology
Head-to-head clinical analysis: BETHKIS versus NEOMYCIN AND POLYMYXIN B SULFATES BACITRACIN ZINC AND HYDROCORTISONE.
Peer-Reviewed Evidence
Head-to-head clinical analysis: BETHKIS versus NEOMYCIN AND POLYMYXIN B SULFATES BACITRACIN ZINC AND HYDROCORTISONE.
BETHKIS vs NEOMYCIN AND POLYMYXIN B SULFATES, BACITRACIN ZINC AND HYDROCORTISONE
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Tobramycin, an aminoglycoside antibiotic, binds to the 30S ribosomal subunit, causing misreading of mRNA and inhibiting protein synthesis, leading to bacterial cell death.
Neomycin, polymyxin B, and bacitracin are topical antibiotics that inhibit bacterial protein synthesis (neomycin and bacitracin) or disrupt bacterial cell membrane permeability (polymyxin B). Hydrocortisone is a corticosteroid that suppresses inflammation by inhibiting phospholipase A2, reducing prostaglandin and leukotriene synthesis.
4 IU/kg (1 mg/kg) intramuscularly or subcutaneously once weekly for 4 weeks, then a maintenance dose of 2 IU/kg (0.5 mg/kg) once weekly.
Apply a thin layer to the affected area 2 to 4 times daily. Ophthalmic: 1-2 drops or a small amount (1/2 inch ribbon) into the conjunctival sac every 4 hours, or more frequently in severe infections. Otic: 4 drops into the affected ear(s) 3-4 times daily. Topical: Apply 2-4 times daily. Route: Topical, ophthalmic, otic.
None Documented
None Documented
Terminal elimination half-life 2-3 hours in patients with normal renal function; prolonged to 20-40 hours in severe renal impairment (CrCl <30 mL/min).
Neomycin: 2-3 hours for absorbed fraction (extensive variability). Polymyxin B: 6-7 hours (prolonged in renal impairment). Bacitracin: 1.5 hours (intramuscular data; topical: negligible). Hydrocortisone: 1.5-2 hours (topical absorption limited).
Primarily renal excretion of unchanged drug via glomerular filtration; ~90% of absorbed dose excreted in urine within 24 hours; biliary/fecal elimination <5%.
Neomycin is primarily excreted unchanged in feces (97%) after oral administration; absorbed fraction is renally excreted. Polymyxin B is mainly eliminated via renal tubular secretion (60-70% unchanged in urine). Bacitracin is predominantly excreted renally (90% unchanged). Hydrocortisone is metabolized hepatically and metabolites are excreted renally. For topical ophthalmic/otic use: negligible systemic absorption; any absorbed drug follows the respective systemic routes.
Category C
Category A/B
Aminoglycoside Antibiotic
Aminoglycoside Antibiotic