Dose and Administration

1. Intravenous bolus over 2-3 minutes, or IM.
2. Loading dose of 4mg/kg.

Indications

1. Empirical therapy for those VLBW infants with risk factors for perinatal sepsis in the first week of life.
2. Proven neonatal sepsis (pneumonia, septicaemia, urinary tract infections, CNS infections, skin, bone and soft tissue infection), with bacteria known to be sensitive (note: Staph epidermidis is resistant).

Contraindications and Precautions

1. Known hypersensitivity to gentamicin/other aminoglycosides.
2. Use in treatment of minor infections.
3. Extreme caution in neonates with renal dysfunction.
4. Caution in concurrent therapy with cephalosporins, potent diuretics such as furosemide, and neuromuscular blocking agents.
5. Concurrent administration with other ototoxic and/or nephrotoxic drugs.

Clinical Pharmacology

Bacteriocidal aminoglycoside antibiotic which inhibits bacterial protein synthesis. Active against a wide variety of pathogenic gram negative and gram positive bacteria, including Escherichia coli, Enterbacter spp, Pseudomonas aeruginosa, Proteus spp, Serratia spp, Staphylococcus spp (including penicillin and methicillin resistant strains).

Poorly absorbed by the oral route, variable absorption from intramuscular injection sites. Diffuses through the plasma and interstitial fluid volumes. Does not penetrate the CSF to any significant extent. Low binding (25-30%) to human plasma protein. Thought to be excreted unchanged, eliminated mainly by the kidney. Renal clearance of gentamicin appears to be slightly less than that of endogenous creatinine. Reduction in serum concentrations can be achieved by peritoneal dialysis or haemodialysis.

Possible Adverse Effects

1. Venous irritation, soft tissue injury at IV injection site.
2. Pain, soft tissue injury at IM injection site.
3. Gastrointestinal disturbance (nausea, vomiting, diarrhoea).
4. Nephrotoxicity.
5. Ototoxicity (vestibular injury irreversible).
6. Neurotoxicity (lethargy, muscle twitching).
7. Blood dyscrasias (rare).
8. Hypersensitivity (rash, urticaria, fever, laryngeal oedema).

Special Considerations

1. May be used in combination with other antibiotics if infused separately. Synergistic effect against several organisms when used with penicillin.
2. Adjust dose and/or dose interval in infants with suspected/proven renal impairment, or reduced renal clearance due to extreme immaturity.
3. Monitoring:
   • For infants who are likely to have their antibiotics ceased at 48 hours, levels are not necessary unless there is concern about renal impairment.
   • For other infants, obtain trough and peak serum levels on the 3^rd dose.
   • Repeat if dose changed.
   • Repeat every 3-5 days.
   • Desired peak level 60 minutes after completion of drug infusion 5-8 mg/L.
   • Trough level immediately prior to the next dose should be 1-2 mg/L.