Aminoglycosides

Question 1

What are aminoglycosides active against?

Answer 1

Gram negative aerobes, Pseudomonas aeruginosa

They are broad spec

Question 2

What are aminoglycosides used for?

Answer 2

• Sepsis
• Pyelonephritis (kidney inflammation)
• Complicated UTI
• Endocarditis
• Pneumonia

Question 3

What are examples of aminoglycosides?

Answer 3

• Gentamicin
• Tobramycin
• Streptomycin (TB)
• Neomycin
• Amikacin

Question 4

In which categories must you determine serum concentrations of gentamicin in?

Answer 4

• Elderly
• Obese
• Cystic Fibrosis
• High doses
• Renal impairment

Question 5

What would you do if the post-dose ‘peak’ level of gentamicin is too high after 1 hour?

Answer 5

• Reduce the dose to 5-10mg/ml (3-5 mg/ml for endocarditis)

Question 6

What would you do if the pre-dose ‘trough’ level of gentamicin before the next dose was too high?

Answer 6

• Increase the interval to <2mg/ml (<1mg/ml for endocarditis)

Question 7

What would you do with gentamicin if the patient was renally impaired?

Answer 7

• Increase interval

Question 8

What would you do in gentamicin if the patient was severely renally impaired (<30ml/min)?

Answer 8

• Reduce dose

Question 9

What if a pregnant patient needed gentamicin?

Answer 9

• You would avoid unless it was absolutely necessary

- If necessary, serum concs must be monitored at all times

Question 10

Who should a once daily dosing regimen be avoided in?

Answer 10

• Renally impaired (<20ml/min)
• Gram positive endocarditis
• Burns covering >20% of the body

Question 11

In multiple dose regimen, which patient group requires more frequent and earlier monitoring?

Answer 11

• Renally impaired

Question 12

What are the side effects of aminoglycosides?

Answer 12

• COMMON - OTOTOXICITY
• nephrotoxicity
• peripheral neuropathy - muscle weakness
• impaired neuromuscular transmission - CI in myasthenia gravis
• Low K, Ca, Mg
• MHRA/CHM - potential for histamine related ADRs

Side effects are dose related - do not exceed 7 days

Question 13

What are signs of nephrotoxicity?

Answer 13

• Low urine output/creatinine clearance

- High serum creatinine/urea

Question 14

Ototoxicity is irreversible, what should patients be advised to report?

Answer 14

• hearing loss
• tinnitus
• vertigo

Question 15

What interacts with aminoglycosides?

Answer 15

• Ciclosporin, tacrolimus, vancomycin = increased risk of nephrotoxicity
• Loop diuretics, cisplatin = increased risk of ototoxicity (space doses further apart)