Today ' s Treatment Use of antibiotics Aminoglycosides

Aminoglycosides are an important group of antibiotics whose basic compounds contain aminosugars. They are produced either by Streptomyces spp (streptomycin, kanamycin, tobramycin, and neomycin) or Micromonospora spp (the gentamicins and sissomicin), which accounts for the different spellings. Semisynthetic derivatives have also been produced (for example, amikacin from kanamycin and netilmicin from sissomicin), and further such compounds are under investigation. Aminoglycosides are not appreciably absorbed from the gut in normal subjects and must be administered by intravenous, intramuscular (or subcutaneous) injection to treat systemic infections, although in patients with impaired renal function prolonged oral administration (as, for example, neomycin in liver failure) may lead to toxic accumulation of the drug in the body. Aminoglycosides are well absorbed from injection sites usually, from the peritoneal space, or from large wounds and granulating areas if applied topically. They are distributed throughout the extracellular water compartment of the bodyachieving concentrations quarter to half of those attained in the serum, in pleural, ascitic, and joint fluids, in bronchial secretions, and in bile. But they pass poorly into the cerebrospinal fluid even when the meninges are inflamed. The aminoglycosides are excreted by glomerular filtration in an active form. Their antimicrobial effect is enhanced by an alkaline pH. When renal function is impaired, serum and tissue concentrations may readily increase to toxic levels. This necessitates regulating dosage carefully in such patients either by serum assay or nomogram based on the serum creatinine concentration.