NEOMYCIN:
A component of neomycin that is produced by Streptomyces fradiae. On hydrolysis it yields neamine and neobiosamine B. (From Merck Index, 11th ed). Neomycin is a bactericidal aminoglycoside antibiotic that binds to the 30S ribosome of susceptible organisms.
Binding interferes with mRNA binding and acceptor tRNA sites and results in the production of non-functional or toxic peptides.
Pharmacology:
Indication : Topical uses include treatment for superficial eye infections caused by susceptible bacteria (used in combination with other antiinfectives), treatment of otitis externa caused by susceptible bacteria, treatment or prevention of bacterial infections in skin lesions, and use as a continuous short-term irrigant or rinse to prevent bacteriuria and gram negative rod bacteremia in abacteriuric patients with indwelling catheters. May be used orally to treat hepatic encephalopathy, as a perioperative prophylactic agent, and as an adjunct to fluid and electrolyte replacement in the treatment of diarrhea caused to enteropathogenic E. coli (EPEC).
Pharmacodynamics:Neomycin is an aminoglycoside antibiotic. Aminoglycosides work by binding to the bacterial 30S ribosomal subunit, causing misreading of t-RNA, leaving the bacterium unable to synthesize proteins vital to its growth. Aminoglycosides are useful primarily in infections involving aerobic, Gram-negative bacteria, such as Pseudomonas, Acinetobacter, and Enterobacter.
In addition, some mycobacteria, including the bacteria that cause tuberculosis, are susceptible to aminoglycosides. Infections caused by Gram-positive bacteria can also be treated with aminoglycosides, but other types of antibiotics are more potent and less damaging to the host. In the past the aminoglycosides have been used in conjunction with penicillin-related antibiotics in streptococcal infections for their synergistic effects, particularly in endocarditis.
Aminoglycosides are mostly ineffective against anaerobic bacteria, fungi and viruses.
Absorption:Poorly absorbed from the normal gastrointestinal tract. Although only approximately 3% of neomycin is absorbed through intact intestinal mucosa, significant amounts may be absorbed through ulcerated or denuded mucosa or if inflammation is present.
Protein bindin :Protein binding studies have shown that the degree of aminoglycoside protein binding is low and, depending upon the methods used for testing, may be between 0% and 30%.
Metabolism :Neomycin undergoes negligible biotransformation after parenteral administration.
Route of elimination:The small absorbed fraction is rapidly distributed in the tissues and is excreted by the kidney in keeping with the degree of kidney function.
Half life :2 to 3 hour
Drug Drug interactions:
Amoxicillin+Neomycin=The serum concentration of Neomycin can be decreased when it is combined with Amoxicillin.
Ampicillin+Neomycin=The serum concentration of Neomycin can be decreased when it is combined with Ampicillin.
Avibactam+Neomycin=Avibactam may increase the nephrotoxic activities of Neomycin.
Azidocillin+Neomycin=The serum concentration of Neomycin can be decreased when it is combined with Azidocillin.
Therapeutic Uses:
>Reducing bacteria in the intestines.
>Neomycin is an aminoglycoside antibiotic. It kills sensitive bacteria by stopping the production of essential proteins needed by the bacteria to survive.
Side effects:
>Diarrhea
>nausea.
>Severe allergic reactions
> bloody stools; dizziness; hearing loss; muscle twitching; ringing in ears
>seizures; skin tingling or numbness
>vaginal irritation or discharge; stomach pain/cramps.
REFERENCE:-Tripathi K D"Essential of medical pharmacology",7th edition ,page no743,750.
No comments:
Post a Comment