Comparative Pharmacology
Head-to-head clinical analysis: GENOPTIC versus NEOMYCIN AND POLYMYXIN B SULFATES AND GRAMICIDIN.
Peer-Reviewed Evidence
Head-to-head clinical analysis: GENOPTIC versus NEOMYCIN AND POLYMYXIN B SULFATES AND GRAMICIDIN.
GENOPTIC vs NEOMYCIN AND POLYMYXIN B SULFATES AND GRAMICIDIN
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Genoptic (gentamicin ophthalmic) is an aminoglycoside antibiotic that inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit, causing misreading of mRNA and production of nonfunctional proteins.
Neomycin and gramicidin are aminoglycoside and polypeptide antibiotics, respectively, that inhibit bacterial protein synthesis by binding to the 30S and 50S ribosomal subunits, while polymyxin B is a cationic detergent that disrupts bacterial cell membrane integrity by binding to lipopolysaccharides.
Instill 1-2 drops into affected eye(s) every 4-6 hours; for severe infections, every 1-2 hours initially, then reduce frequency as improvement occurs.
1-2 drops or a small amount applied to affected eye(s) every 4 hours, or more frequently if severe, for up to 7-10 days. Ophthalmic ointment: apply a 1/2-inch ribbon into conjunctival sac every 3-4 hours.
None Documented
None Documented
2-3 hours (prolonged in renal impairment to 18-24 hours); in neonates, 3-8 hours.
Neomycin: plasma half-life ~2-3 hours in patients with normal renal function, but can extend to 12-24 hours or more in renal impairment. Polymyxin B: half-life ~6 hours in normal renal function, prolonged significantly in renal failure (up to 2-3 days). Gramicidin: not systemically absorbed; half-life not applicable.
Primarily renal (70-90% unchanged) via glomerular filtration and tubular secretion; biliary/fecal <5%.
Neomycin and polymyxin B sulfates and gramicidin are poorly absorbed from intact skin or ophthalmic sites. After topical application, absorbed neomycin is excreted primarily unchanged in urine (30-50% of absorbed dose) via glomerular filtration; polymyxin B is excreted slowly via renal tubular secretion and glomerular filtration (60-70% of absorbed dose in urine); fecal elimination accounts for minor amounts. Gramicidin is not significantly absorbed.
Category C
Category A/B
Aminoglycoside Antibiotic
Aminoglycoside Antibiotic