aminoglycosides

1. AMINOGLYCOSIDES

2.  Waksman in 1944 – discovered Streptomycin
 Source :
Streptomyces – ‘ mycins’ ( e.g. Streptomycin)
Micromonospora – ‘micins’ (e.g. Gentamicin)

3. Classification
Systemic aminoglycosides
• Streptomycin
• Gentamicin
• Kanamycin
• Tobramycin
• Amikacin
Topical aminoglycosides
• Neomycin
• Framycetin

4. Common properties of aminoglycosides
1. Consists of two or more amino sugars joined
to a hexose nucleus by glycosidic linkage.
2. Highly polar – administered parenterally for
systemic effect.
3. Distributed extracellularly , do not penetrate
brain or CSF.
4. Excreted unchanged in urine by glomerular
filtration (t1/2 – 2 to 3 hrs).

5. 5. Bactericidal action – aerobic gram negative bacilli.
6. Acts by inhibiting bacterial protein synthesis.
7. There is partial cross-resistance among them.
8. Exhibits ototoxicity & nephrotoxicity.
9. Transport of aminoglycosides into the bacterial cell
requires oxygen – anaerobes are resistant.
10. Exhibits synergism when combined with β-lactam
antibiotics.

6. Therapeutic uses
 Urinary tract infections
 Bacterial endocarditis
 Tuberculosis
 Plague
 Tularemia
 Brucellosis
Topical use
Gentamicin, tobramycin, neomycin, framycetin
– gram –ve skin, eye and ear infections

7. Adverse effects
1.Ototoxicity
Cochlear & vestibular damage
2. Nephrotoxicity – reversible
3.Neuromuscular blockade
• inhibits Ach release from the motor nerve
endings
• apnoea, paralysis

8. 4.Hypersensitivity reactions
5.Local irritation
pain, paresis, respiratory depression,
nystagmus & convulsions
6. Superinfection

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