Neomycin: Uses, Dosage, Side Effects, and Precautions

Neomycin

Description:
Neomycin is an aminoglycoside antibiotic that is primarily used to prevent or treat bacterial infections in the intestines, skin, and eyes. It works by inhibiting bacterial protein synthesis, leading to the death of the bacteria. Neomycin is not absorbed well in the gastrointestinal tract, making it useful for infections within the GI tract, but it can be toxic when used systemically.

Available Brand Names (examples include):

1. Neosporin (combined with other antibiotics like polymyxin and bacitracin)
2. Mycifradin
3. Neo-Tab
4. Neo-Rx
5. NeoDecadron (with dexamethasone)

Available Forms and Strengths:

• Oral Tablets: 500 mg
• Topical Cream/Ointment: 0.5%
• Eye/Ear Drops: 0.35%, 0.5%
• Oral Solution: 125 mg/5 mL
• Topical Powder

Uses:

• Prevention of bacterial infections in the intestines before surgery.
• Treatment of hepatic encephalopathy (to reduce ammonia-producing bacteria in the gut).
• Topical application for minor skin infections (wounds, burns, cuts).
• Treatment of eye and ear infections (as eye/ear drops).
• Used in combination with other antibiotics (e.g., in Neosporin) to treat skin infections and wounds.

Side Effects:

• Nephrotoxicity (kidney damage) when used in large or prolonged doses.
• Ototoxicity (hearing loss), especially with long-term use.
• Contact dermatitis (skin irritation from topical application).
• Diarrhea, nausea, and vomiting (when used orally).
• Superinfection (overgrowth of non-susceptible bacteria or fungi).
• Neuromuscular blockade (muscle weakness, rare but serious).

Dosage:

• Oral (for bowel preparation):
• Adults: 1 gram (1000 mg) every 6 hours for 3-4 days before surgery.
• Hepatic encephalopathy:
• Adults: 4-12 grams/day divided into 3-4 doses for up to 2 weeks.
• Topical (skin infections):
• Apply to affected areas 1-3 times daily.
• Eye/Ear drops:
• Apply 1-2 drops every 2-4 hours depending on the severity of the infection.

Contraindications:

• Hypersensitivity to neomycin or other aminoglycosides.
• Patients with pre-existing kidney disease (due to potential nephrotoxicity).
• Myasthenia gravis (can worsen muscle weakness).
• Pregnancy (use with caution due to potential ototoxicity for the fetus).
• Patients with intestinal obstruction (if used orally).

Drug Interactions:

• Other nephrotoxic drugs (e.g., vancomycin, NSAIDs) – increased risk of kidney damage.
• Loop diuretics (e.g., furosemide) – increased risk of ototoxicity.
• Neuromuscular blocking agents – may increase the risk of muscle paralysis.
• Oral anticoagulants – may enhance their effect and increase bleeding risk.

Warnings/Precautions:

• Kidney function should be monitored in patients receiving oral neomycin, particularly if used long-term or at high doses.
• Regular hearing tests should be performed if neomycin is used for extended periods to detect early signs of ototoxicity.
• Prolonged use may lead to bacterial resistance or superinfection with non-susceptible organisms.
• Avoid prolonged or excessive topical use to prevent skin irritation and absorption leading to toxicity.

Doctor’s Advice:

• Do not use neomycin for more than the recommended duration, as prolonged use increases the risk of side effects.
• Report any signs of hearing loss, dizziness, or kidney problems to your doctor.
• For skin infections, apply only to small areas to minimize absorption.
• Avoid using other nephrotoxic or ototoxic medications unless advised by a healthcare provider.

Would you like more detailed information on its use for specific conditions, or its combination with other drugs (e.g., in Neosporin)?