1. Chapter 38 Aminoglycosides
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2. Commonly used aminoglycosides
Gentamicin (庆大霉素)
Streptomycin (链霉素)
Amikacin （ 阿米卡星、丁胺卡那霉素）
Netilmicin (奈替米星)
Kanamycin (卡那霉素)
Tobramycin (妥布霉素)
Neomycin (新霉素)
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3. Pharmacokinetics
1. Oral absorption: poor (be given parenterally); be given orally to eradicate intestinal bacteria; 2. Excretion: rapidly excreted by the kidney; short half-lives; 3. Distribution: do not cross the blood-brain barrier, but they cross the placenta; Blood concentrations should be measured to guide dosing.
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4. Antibacterial mechanism:
Spectrum of activity:
1. Active against many Gram-negative bacteria (including Pseudomonas species ) and some Gram-positive bacteria.
2. Streptomycin: Mycobacterium tuberculosis
3. Inactive against anaerobes, which are unable to take up the aminoglycosides;
Antibacterial mechanism:
Inhibit bacterial protein synthesis (bactericidal)
假单胞菌
结核杆菌
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5. Indications: infections caused by sensitive gram-negative bacilli (urinary, respiratory, and biliary systems);
Drug resistance:
1. Production of enzymes that acetylate, phosphorylate or adenylyl aminoglycosides;
2. Reduced penetration of the drug (can be overcome by co-administration of antibacterials that disrupt cell wall synthesis , such as penicillins);
3. Changes in the ribosomal proteins in bacteria;
Streptomycin has cross-resistance with getamicin, kanamycin and neomycin
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6. Adverse reactions
Ototoxicity: disturbances of balance or deafness that are often irreversible; caused by accumulation of the aminoglycoside in the inner ear.
Nephrotoxicity: usually reversible; defect in
the concentrating ability of the kidney, with mild proteinuria followed by a reduction in the glomerular filtration rate; caused by retention of aminoglycosides in the proximal tubular cells of the kidney;
Neuromuscular blockade: usually occurs when used with anesthetic drugs;
Allergic reactions
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7. Gentamycin
[,dʒentə‘maisin] 庆大霉素
Uses: 1. Infection by gram-negative bacilli 2. Pseudomonas aeruginosa: in combination with carbencillin; 3. bacterial endocarditis: with penicillin 4. Polyinfection: with cephalosporin or carbencillin ； 5. Oral: bowel infection, helicobacter pylori ulcer.
绿脓杆菌
羧苄西林
幽门螺杆菌溃疡
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8. Streptomycin Uses: pestis , tuberculosis (second line) Amikacin Uses: Infection by gram-negative bacilli more resistant to modifying enzyme
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