Aminoglycosides

Question 1

Give some examples of aminoglycosides.

Answer 1

Amikacin, gentamicin, neomycin, streptomycin, tobramycin.

Question 2

Describe how gentamicin is given.

Answer 2

Single or multiple daily doses. 7mg/kg/day.

Question 3

What is the mode of action of the aminoglycosides?

Answer 3

Irreversibly binding to the 30S ribosome, inhibiting proteins synthesis. Creates fissures, allowing more antibiotic in and leakage of cellular contents.

Question 4

Against which organisms are aminoglycosides active?

Answer 4

Some gram-positive and many gram-negative.

Question 5

Give some indications for which aminoglycosides may be prescribed to treat?

Answer 5

Endocarditis, septicaemia, meningitis and other CNS infections, biliary-tract infections, prostitis, pneumonia.

Question 6

Which aminoglycosides are effective against Pseudomonas aeruginosa?

Answer 6

Amikacin, gentamicin and tobramycin.

Question 7

Which aminoglycosides are effective against Mycobacterium tuberculosis (TB)?

Answer 7

Streptomycin.

Question 8

What are some side effects associated with aminoglycoside use?

Answer 8

Impairment of neuromuscular transmission, irreversible ototoxicity, nephrotoxicity, nausea, vomiting, antibiotic associated colitis, peripheral neuropathy, electrolyte disturbance.

Question 9

In which patients should aminoglycosides be used with caution?

Answer 9

Patients with conditions characterised by muscular weakness e.g. myasthenia gravis.

Question 10

Aminoglycosides should be avoided in patients who are taking other ototoxic drugs, give some examples.

Answer 10

Cisplatin, furosemide.

Question 11

What monitoring should be carried out when treating patients with aminoglycosides?

Answer 11

Serum-aminoglycoside concentrations should be measured in all patients receiving parenteral aminoglycosides. Renal function should be assessed before start and auditory and vestibular function measures.

Question 12

Are aminoglycosides absorbed from the gut?

Answer 12

No.

Question 13

Which aminoglycoside is used to reduce the bacterial population of the colon prior to bowel surgery or in hepatic failure?

Answer 13

Neomycin.

Question 14

When measuring the serum-aminoglycoside concentration, when is considered peak level?

Answer 14

One hour post dose.

Question 15

When measuring the serum-aminoglycoside concentration, when is considered though level?

Answer 15

Before the next dose.

Question 16

If serum-aminoglycoside concentration is high when measuring the peak level, what should be done?

Answer 16

Reduce next dose to ensure next peak is lower.

Question 17

If serum-aminoglycoside concentration is high when measuring trough level, what should be done?

Answer 17

Dosage interval should be increased.