What is the proper use and dosage of Neomycin (antibiotic) for pre-surgical prophylaxis and treating bacterial infections?

Neomycin: Proper Use and Dosage

Neomycin is primarily indicated for bowel preparation before elective colorectal surgery at 1 gram orally combined with erythromycin base 1 gram at 1:00 p.m., 2:00 p.m., and 11:00 p.m. on the day before surgery, and should never be used systemically due to severe nephrotoxicity and irreversible ototoxicity risks. 1

Pre-Surgical Prophylaxis for Colorectal Surgery

Standard Bowel Preparation Regimen

• Administer neomycin 1 gram orally plus erythromycin base 1 gram orally at three specific times on the day before surgery: 1:00 p.m., 2:00 p.m., and 11:00 p.m. 1
• This oral antibiotic regimen is given in conjunction with mechanical bowel preparation using magnesium sulfate and bisacodyl 1
• The patient should be on clear liquid diet the day before surgery with supplemental IV fluids as needed 1

Alternative Bowel Preparation Dosing

• Neomycin may be dosed at 1-2 grams orally with variable timing as part of bowel preparation protocols 2
• This is typically combined with metronidazole 1-2 grams orally or erythromycin base 1-2 grams orally 2

Critical Safety Warnings

Absolute Contraindications for Systemic Use

Neomycin should NEVER be used intravenously, intramuscularly, or for wound irrigation due to life-threatening toxicity. The evidence is unequivocal:

• Nephrotoxicity and permanent ototoxicity are the most hazardous side effects, occurring even with topical or irrigant use 3, 4
• Profound, irreversible hearing loss has been documented following topical neomycin application to wounds, with toxic serum levels persisting for days after discontinuation 3, 5, 4
• Patients with renal impairment are at extremely high risk for permanent deafness even with topical use 5, 6

Monitoring Requirements for Oral Use

• Limit oral neomycin treatment to the shortest possible duration—bowel preparation should not exceed the single-day protocol 1
• For hepatic coma (the only other FDA-approved indication), treatment should not exceed 5-6 days, with mandatory frequent monitoring for toxicity 1
• Serum neomycin concentrations must be monitored if extended use beyond bowel preparation is required 1

NOT Recommended for Urinary Tract Infections

• While historical data from 1956 showed neomycin could treat gram-negative urinary infections at 0.5 grams every 12 hours for 5 days, this is obsolete practice 7
• Modern urologic surgery guidelines explicitly state fluoroquinolones have no place in urologic prophylaxis except for prostate biopsy, and neomycin is only listed for bowel preparation 2
• Safer alternatives (fluoroquinolones, cephalosporins, aminoglycosides IV) are available for genitourinary procedures 2

Common Pitfalls to Avoid

• Never use neomycin for wound irrigation or topical application to large open wounds—systemic absorption causes irreversible ototoxicity 3, 4
• Never extend oral neomycin beyond the single-day bowel preparation protocol unless treating hepatic coma with intensive monitoring 1
• Never use neomycin in patients with renal impairment even for bowel preparation—the risk of permanent deafness is unacceptably high 5, 6
• Do not confuse neomycin with other aminoglycosides (gentamicin, tobramycin, amikacin) that can be given IV for surgical prophylaxis at appropriate doses 2