Basic Profile / Key Facts
Drug Category
- Anti-bacterial Agents
- Aminoglycosides
Dosage Forms
Indications
For the treatment of bacteremia, septicaemia, respiratory tract infections, skin and soft-tissue infection, burns, wounds, and peri-operative infections caused by susceptible strains.
Pharmacology
Netilmicin is a semisynthetic, water soluble antibiotic of the aminoglycoside group, produced by the fermentation of Micromonospora inyoensis, a species of actinomycete. Aminoglycosides are useful primarily in infections involving aerobic, Gram-negative bacteria, such as Pseudomonas, Acinetobacter, and Enterobacter. It is active at low concentrations against a wide variety of pathogenic bacteria including Escherichia coli, bacteria of the Klebsiella-Enterobacter-Serratia group, Citrobacter sp., Proteus sp. (indole-positive and indole-negative), including Proteus mirabilis, P. morganii, P. rettgrei, P. vulgaris, Pseudomonas aeruginosa and Neisseria gonorrhoea. Netilmicin is also active in vitro against isolates of Hemophilus influenzae, Salmonella sp., Shigella sp. and against penicillinase and non-penicillinase-producing Staphylococcus including methicillin-resistant strains. Some strains of Providencia sp., Acinetobacter sp. and Aeromonas sp. are also sensitive to netilmicin. Many strains of the above organisms which are found to be resistant to other aminoglycosides, such as kanamycin, gentamicin, tobramycin and sisomicin, are susceptible to netilmicin in vitro. Occasionally, strains have been identified which are resistant to amikacin but susceptible to netilmicin. The combination of netilmicin and penicillin G has a synergistic bactericidal effect against most strains of Streptococcus faecalis (enterococcus). The combined effect of netilmicin and carbenicillin or ticarcillin is synergistic for many strains of Pseudomonas aeruginosa. In addition, many isolates of Serratia, which are resistant to multiple antibiotics, are inhibited by synergistic combinations of netilmicin with carbenicillin, azlocillin, mezlocillin, cefamandole, cefotaxime or moxalactam. Aminoglycosides are mostly ineffective against anaerobic bacteria, fungi and viruses.
Mechanism of Action
Aminoglycosides like netilmicin "irreversibly" bind to specific 30S-subunit proteins and 16S rRNA. Specifically netilmicin binds to four nucleotides of 16S rRNA and a single amino acid of protein S12. This interferes with decoding site in the vicinity of nucleotide 1400 in 16S rRNA of 30S subunit. This region interacts with the wobble base in the anticodon of tRNA. This leads to interference with the initiation complex, misreading of mRNA so incorrect amino acids are inserted into the polypeptide leading to nonfunctional or toxic peptides and the breakup of polysomes into nonfunctional monosomes, leaving the bacterium unable to synthesize proteins vital to its growth.
Absorption
Rapidly and completely absorbed after IM administration, peak serum levels were achieved within 30-60 minutes. Aminoglycosides are poorly absorbed from the gastrointestinal tract.
Toxicity
Netilmicin has the potential to cause disturbances in balance and a hearing loss.
Biotrnasformation / Drug Metabolism
No evidence of metabolic transformation, typically 80% is recoverable in the urine within 24 hours
Contraindications
Patients with a history of hypersentivity to aminoglycosides or those with impaired
renal function should avoid this medication.
Drug Interactions
Netilmicin should not be administered concomitantly with potent loop diuretics such as
furosemide and ethacrynic acid as the potential for ototoxicity is enhanced by the combination.
|
