Usage
Netilmicin is an aminoglycoside antibiotic primarily used to treat serious bacterial infections caused by susceptible gram-negative bacteria, especially those resistant to gentamicin. These infections may include:
- Respiratory tract infections (e.g., pneumonia, bronchitis)
- Urinary tract infections (UTIs), including complicated UTIs and pyelonephritis
- Skin and soft tissue infections
- Intra-abdominal infections
- Septicemia
- Bone and joint infections
- Gynecological infections
- Bacterial meningitis
- Endocarditis (in combination with other antibiotics)
It can also be used for surgical prophylaxis. Netilmicin exerts its bactericidal effect by inhibiting bacterial protein synthesis.
Alternate Names
- Generic Name: Netilmicin Sulfate
- Brand Names: Netromycin, Netspan, Netilcin, Netilmac, Internet (regional variations exist)
How It Works
Pharmacodynamics: Netilmicin irreversibly binds to the 30S ribosomal subunit of susceptible bacteria. This binding interferes with the initiation complex formation between messenger RNA (mRNA) and the 30S subunit, leading to misreading of the genetic code on the mRNA template. Consequently, protein synthesis is inhibited, resulting in bacterial cell death.
Pharmacokinetics:
- Absorption: Netilmicin is not absorbed orally and is administered parenterally (IM or IV). After IM administration, absorption is rapid and complete.
- Distribution: Widely distributed in extracellular fluids, reaching therapeutic levels in various tissues and organs. It can cross the placental barrier and is found in breast milk.
- Metabolism: Not significantly metabolized.
- Elimination: Primarily excreted unchanged by the kidneys through glomerular filtration. Dose adjustment is necessary in patients with renal impairment.
Dosage
Standard Dosage
Adults:
- Serious systemic infections: 4-6 mg/kg/day, divided into two or three equal doses every 8 or 12 hours, or as a single daily dose. Maximum daily dose: 7.5 mg/kg.
- Urinary tract infections: 150 mg as a single daily dose for 5 days (uncomplicated UTI), or 3-4 mg/kg/day in divided doses every 12 hours (complicated UTI).
Children:
- Neonates <1 week: 6 mg/kg/day, divided every 12 hours.
- Neonates >1 week and infants: 7.5-9 mg/kg/day, divided every 8 hours.
- Older children: 6-7.5 mg/kg/day, divided every 8 hours.
- Alternative regimen (Neonates <6 weeks): 4-6.5 mg/kg/day, divided every 12 hours.
- Alternative regimen (Older infants and children): 5.5-8 mg/kg/day, divided every 8 or 12 hours.
Special Cases:
- Elderly Patients: Dose adjustment based on renal function is crucial.
- Patients with Renal Impairment: Reduce dose or prolong dosing interval based on creatinine clearance. Hemodialysis requires 50% of the initial loading dose after dialysis.
- Patients with Hepatic Dysfunction: No dose adjustment is typically required.
- Patients with Comorbid Conditions: Careful monitoring is required, particularly for those with myasthenia gravis, parkinsonism, or pre-existing hearing or kidney problems.
Clinical Use Cases
Dosing for clinical use cases such as intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations should be determined by individual assessment and consideration of the severity of infection and patient’s condition. Usual recommendations for systemic infections apply as a starting point.
Dosage Adjustments
Dosage adjustments are required in patients with renal impairment based on creatinine clearance:
- CrCl 20-40 mL/min: Administer the usual dose every 24 hours.
- CrCl 40-60 mL/min: Administer the usual dose every 12 hours.
Adjustments should also be made for patients with burns or other conditions affecting drug pharmacokinetics.
Side Effects
Common Side Effects
- Nausea, vomiting
- Headache
- Skin rash or itching
- Pain and inflammation at the injection site
- Weakness
Rare but Serious Side Effects
- Nephrotoxicity (kidney damage)
- Ototoxicity (hearing loss, vestibular toxicity)
- Neuromuscular blockade (respiratory paralysis, especially with concurrent use of neuromuscular blocking agents)
- Neurotoxicity (seizures, confusion)
- Allergic reactions
Long-Term Effects
- Permanent hearing loss or kidney damage with prolonged high-dose therapy
Adverse Drug Reactions (ADR)
- Anaphylaxis
- Stevens-Johnson syndrome
Contraindications
- Hypersensitivity to netilmicin or other aminoglycosides.
- Myasthenia gravis
Drug Interactions
- Other nephrotoxic/ototoxic drugs: (e.g., loop diuretics, vancomycin, cisplatin, amphotericin B) – Increased risk of nephrotoxicity/ototoxicity.
- Neuromuscular blocking agents: (e.g., succinylcholine, pancuronium) – Enhanced neuromuscular blockade, potentially leading to respiratory paralysis.
- Cephalosporins, penicillins: In vitro inactivation. Administer separately.
- Other aminoglycosides: Avoid concomitant use.
Pregnancy and Breastfeeding
- Pregnancy: Category D. Not recommended due to potential fetal harm.
- Breastfeeding: Netilmicin is excreted in breast milk. Not recommended due to the potential risk for neonatal toxicity.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.
- Side Effects: Nephrotoxicity, ototoxicity, nausea, vomiting, weakness.
- Contraindications: Hypersensitivity to aminoglycosides, myasthenia gravis.
- Drug Interactions: Other nephrotoxic/ototoxic drugs, neuromuscular blocking agents, cephalosporins, penicillins.
- Pregnancy & Breastfeeding: Not recommended.
- Dosage: Refer to dosage section above.
- Monitoring Parameters: Renal function (serum creatinine, creatinine clearance), auditory function (audiometry), vestibular function, peak and trough serum netilmicin levels.
Popular Combinations
Netilmicin is sometimes used in combination with beta-lactam antibiotics for synergistic effects against certain bacterial infections.
Precautions
- Monitor renal, auditory, and vestibular function.
- Maintain adequate hydration.
- Patients with renal impairment require dose adjustment.
- Use with caution in neonates, children, elderly, and patients with neuromuscular disorders.
- Avoid concurrent use of other nephrotoxic or ototoxic drugs.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Netilmicin?
A: See detailed dosage section above.
Q2: What are the most serious side effects of Netilmicin?
A: Nephrotoxicity (kidney damage) and ototoxicity (hearing loss or balance problems) are the most serious side effects.
Q3: Can Netilmicin be used during pregnancy or breastfeeding?
A: No, it’s generally contraindicated due to the risk of fetal/neonatal harm.
Q4: How is Netilmicin administered?
A: Intramuscularly (IM) or intravenously (IV).
Q5: What should be monitored during Netilmicin therapy?
A: Renal function, auditory and vestibular function, and netilmicin serum levels.
Q6: What infections is Netilmicin commonly used to treat?
A: Serious gram-negative infections, including respiratory, urinary tract, skin/soft tissue, intra-abdominal, and bloodstream infections.
Q7: What if a dose of Netilmicin is missed?
A: Administer the missed dose as soon as remembered, unless it’s almost time for the next dose. Do not double the dose.
Q8: What are the signs of an allergic reaction to Netilmicin?
A: Rash, itching, swelling, difficulty breathing, dizziness. Seek immediate medical attention if these occur.
Q9: Can Netilmicin be used in patients with kidney disease?
A: Yes, but with careful dose adjustment based on creatinine clearance.
