What is Amikacin?

Amikacin is a semisynthetic aminoglycoside antibiotic. It was derived by the addition of the (S)-4-amino-2-hydroxybutyryl (AHB) side-chain into the 1-amino position of the deoxystreptamine moiety of kanamycin A.  Clinically, the drug is used as the sulfate. The drug is almost identical with kanamycin in its physical, chemical, pharmacologic, and toxicologic properties. The presence of the AHB side-chain gives amikacin stability against most of the bacterial plasmid-mediated enzymes, which are responsible for resistance to aminoglycosides. For this reason, amikacin is active against many gentamicin- and tobramycin-resistant Gramnegative bacilli.

Mechanism  Of Drug Action

This is probably similar to that of other aminoglycosides, such as gentamicin, that inhibit protein synthesis by binding to the 30S ribosome. Exposure of Gram-negative bacilli to amikacin shows initially a reduction in the number of ribosomes in the center of the cell and an aggregation of nuclear material in a concentric pattern. This is followed in a few hours by rupture of the cytoplasmic membrane, damaged cell walls, and even complete loss of cellular shape. Thus, cell death induced by amikacin appears to be due to lysis.

Drug interactions 

Amikacin is the most stable of the aminoglycoside antibiotics to inactivation by various penicillins. The drug also appears to be very stable to inactivation by penicillins in vivo. The elimination half-life of amikacin in patients with end-stage renal impairment was the same when amikacin was administered alone (66.0 hours) and administered simultaneously with carbenicillin (64.5 hours). In contrast, gentamicin elimination half-life was significantly shortened by concomitant dosing of carbenicillin.

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