Aminoglycosides Flashcards
1
Q
What is an example of an aminoglycoside?
A
• Gentamicin (Cidomycin)
2
Q
What is the method of action of aminoglycosides?
A
- Severe infections with gram –ve aerobes (inc. pseudomonas aeruginosa)
- Gram –ve aerobic bacteria, staphylococci and mycobacteria
- Enter bacterial cells via oxygen dependent transport system
- Binds irreversibly to bacterial ribosome 30S subunit
- Inhibits protein synthesis
- Kill bacteria via a additional unknown mechanism
- Cannot be given orally due to it being highly polarised so does not cross the lipid membranes
3
Q
What are the indications for aminoglycosides?
A
- Severe sepsis – inc. when source is unidentified. Lacks activity against streptococci and anaerobes so should be combined with penicillin and/or metronidazole when organism is unknown
- Pyelonephritis
- Complicated UTI’s
- Biliary and intra-abdominal sepsis
- Endocarditis
4
Q
What are the contraindications with aminoglycosides?
A
- Neonates – monitor dose very carefully due to ↑ risk of side effects
- Elderly – monitor dose very carefully due to ↑ risk of side effects
- Renal impairment – monitor dose very carefully due to ↑ risk of side effects
- Myasthenia gravis – aminoglycosides impair neuromuscular transmission
5
Q
What are the side effects of aminoglycosides?
A
- Nephrotoxicity – accumulate in renal tubular epithelial cells, triggering apoptosis and cell death
- ↓ urine output
- ↑ serum creatinine/urea
- Ototoxicity – accumulate in cochlear and vestibular hair cells, triggering apoptosis and cell death
- Hearing loss
- Tinnitus
- Vertigo
6
Q
What drugs interact with aminoglycosides?
A
- Loop diuretic – ototoxicity ↑ likely
- Vancomycin – ototoxicity/ nephrotoxicity ↑ likely
- Ciclosporin – nephrotoxicity ↑ likely
- Platinum chemotherapy – nephrotoxicity ↑ likely
- Cephalosporins – nephrotoxicity ↑ likely
7
Q
What route are aminoglycosides eliminated?
A
Urine
