Нетилмицин

Описание

This is a semisynthetic derivative of sisomicin, which was developed by ethylation of the 1-N position of the deoxystreptamine ring of sisomicin . Clinically, netilmicin is used as a sulfate. Netilmicin has a similar in vitro antibacterial spectrum to that of gentamicin but, unlike sisomicin, it is active against a proportion of gentamicin-resistant Gram-negative bacilli. However, netilmicin is not active against as wide a range of gentamicin-resistant Gram-negative bacilli as amikacin. Nevertheless, it may be occasionally indicated as an alternative to amikacin for the treatment of infections caused by gentamicin-resistant but netilmicin-susceptible Gram-negative organisms. The following details apply only to netilmicin

Антимикробная активность

It is active against a wide range of enterobacteria as well as many Acinetobacter, Pseudomonas, Citrobacter, Proteus and Serratia spp. Staphylococci, including methicillin-resistant and coagulase-negative strains, are usually susceptible. Nocardiae are inhibited by 0.04–1 mg/L. Providencia spp. and anaerobic bacteria are generally resistant.
It is active against some gentamicin-resistant strains, particularly those that synthesize ANT(2″) or AAC(3)-I. It exhibits typical aminoglycoside properties: bactericidal activity at or close to the MIC; greater activity at alkaline pH; depression of activity against Pseudomonas by divalent cations; and synergy with β-lactam antibiotics. Bactericidal synergy can be demonstrated regularly with benzylpenicillin against viridans streptococci and E. faecalis, but seldom against E. faecium, which characteristically synthesizes AAC(6′), to which netilmicin is susceptible.

Приобретенная устойчивость

It is resistant to ANT(2), AAC(3)-I and AAC(3)-III, but sensitive to AAC(6). AAC(3)-II confers resistance, but generally to a lesser degree than to gentamicin.
Resistance rates are generally about the same as, or a little lower than, those for gentamicin.

Фармаколо?гия

Netilmicin is also highly effective with respect to Gram-negative microorganisms (blue-pus and colon bacilli, rabbit fever, serratia, providencia, enterobacteria, proteus, salmonella, shigella), as well as a few Gram-positive microorganisms (staphylococci and a few strains of streptococci).
It is used for severe bacterial infections that are caused by microorganisms sensitive to the drug. Synonyms of this drug are netillin, zetamycin, and others.

Клиническое использование

Severe infections (including septicemia, lower respiratory tract infections, urinary tract infections, peritonitis, endometritis) caused by susceptible strains of Gram-negative bacilli and staphylococci

Побочные эффекты

It is considered to be less nephrotoxic than gentamicin, a difference not easily explained since the renal clearance and renal and medullary concentrations of the drugs appear to be similar. Both vestibular and cochlear toxicity appear to be low and vestibular toxicity without audiometric abnormality is rare. In some patients, plasma concentrations up to 30 mg/L over periods exceeding 1 week have not resulted in ototoxicity. Evidence of some renal toxicity in the excretion of granular casts has occurred fairly frequently in patients receiving 7.5 mg/kg per day, and is more likely to occur in the elderly and in those receiving higher doses or longer courses. In patients treated for an average of 35 days with 2.4–6.9 mg/kg per day, there was no effect on initially normal renal function, even in the elderly. Long-term treatment led to an increase in elimination half-life from 1.5 to 1.9 h. Nephrotoxicity has been observed in some diabetic patients. Overall estimates of the frequency of nephrotoxicity have ranged from 1% to 18%. Increases in serum transaminase and alkaline phosphatase concentrations have been seen in some patients without other evidence of hepatic impairment.
Once-daily dosing is thought to be safer than twice or three times daily dosing.

взаимодействия лекарств

Netilmicin is inactivated less than gentamicin and tobramycin by high concentrations of various penicillins . At the highest penicillin concentration studied (500 mg/ml), inactivation of netilmicin was a little higher than amikacin. The in vivo inactivation of netilmicin was compared with gentamicin in patients with end-stage renal disease. The terminal elimination half-life for gentamicin decreased from 60 to 25 hours, whereas the values for netilmicin remained essentially the same at 42 to 40 hours. Such patients receiving combinations of netilmicin and various penicillins will not require further dose adjustment. Netilmicin differed from other aminoglycosides by reducing T3 or triiodothyroxime levels in serum.