Aminoglycosides Flashcards
Give 4 examples of aminoglycosides
- Gentamicin
- Amikacin
- Neomycin
- Tobramycin
What is the mechanism of action of aminoglycosides?
Inhibit bacterial synthesis by irreversibly binding to the 30d subunit on the ribosome, preventing elongation of the bacterial protein chain
Are aminoglycosides broad spectrum or narrow spectrum?
Narrow
What bacteria are aminoglycosides effective against?
Gram +ve and some -ve bacteria
Not effective against anaerobes
What are the routes of delivery of aminoglycosides?
- IV
- I’m
- Topical, e.g. Eye/ear drops
Why are aminoglycosides not given orally?
They are not well-absorbed in the gut
How long can you give parenteral antibiotic treatment for?
Avoid giving for more than 7 days
What are the indications for aminoglycosides?
- Meningitis
- Sepsis
- Hospital acquired pneumonia
- Biliary tract infections
- Acute pyelonephritis and prostatitis
- Endocarditis
- Pseudomonas aeruginosa infections
What are the contraindications to aminoglycosides?
- Myasthenia gravis
- Grommets in situ (for intra-aural use)
What are the cautions for aminoglycosides?
- Severe renal impairment or renal failure
- 2nd and 3rd trimester of pregnancy
Why should aminoglycosides not be given in patients with myasthenia gravis?
They are known to impair neuromuscular transmission
Why should caution be taken when using aminoglycosides in severe renal impairment or renal failure?
Aminoglycosides undergo renal excretion
Why should aminoglycoside use be avoided in the 2nd and 3rd trimester?
Due to risk of causing auditory or vestibular nerve damage in infant
What monitoring is required with aminoglycosides?
- Check renal function at baseline and during review appointments as per local guidelines
- Serum aminoglycoside levels should be monitored as per local protocols
Why is it important to check renal function before starting aminoglycosides?
Avoids excessive or sub-therapeutic treatment
What are the target serum gentamicin levels?
5-12mg/L at peak, <2mg/L trough
What might interact with aminoglycosides?
- Loop diuretics
- Vancomycin
- NSAIDs
- Cephalosporins
- Ciclosporins
- Aciclovir
- Cisplatin
- Trimethoprim
- Digoxin
What might happen if you give loop diuretics with aminoglycosides?
Increased risk of ototoxicity
What might happen if you give vancomycin with aminoglycosides?
Increased risk of otoxicity
What might happen if you give NSAIDs with aminoglycosides?
Increased risk of nephrotoxicity
What might happen if you give cephalosporins with aminoglycosides?
Increased risk of nephrotoxicity
What might happen if you give ciclosporins with aminoglycosides?
Increased risk of nephrotoxicity
What might happen if you give cisplatin with aminoglycosides?
Increased risk of nephrotoxicity
What might happen if you give aciclovir with aminoglycosides?
Increased risk of nephrotoxicity
What might happen if you give trimethoprim with aminoglycosides?
Increased risk of nephrotoxicity
What might happen if you give digoxin with aminoglycosides?
Potential increase in serum digoxin concentration
What are the side effects of aminoglycosides?
- Antibiotic associated colitis
- Electrolyte disturbances
- Hypocalcaemia
- Hypokalaemia
- Hypomagnesaemia
- Nausea
- Peripheral neuropathy
- Nephrotoxicity
- Ototoxicity
- Neurotoxicity
What counselling needs to be given to patients on aminoglycosides?
- Complete antibiotic course
- Report problems with hearing or balance and stop drug
What counselling needs to be given regarding hearing and balance to patients on aminoglycosides?
Aminoglycosides may cause ototoxicity, hence patients should be advised to stop taking drug if hearing loss, tinnitus, or problems with balance develop, and to inform their doctor of these changes
