Aminolgycosides

Question 1

How does ahminoglycosides work ?

Answer 1

bind irreversibly to bacterial ribosomes: Active against gram-negative aerobe; P. aeruginosa
- Broad spectrum+ bactericidal

Question 2

What are the uses of aminoglycosides ?

Answer 2

severe sepsis
pyelonephritis
complicated UTI
endocarditis

Question 3

Why aminglycosides are given via parenteral injection ?

Answer 3

not absorbed by the gut

Question 4

Name all aminoglycosides available ?

Answer 4

gentamicin
tobramycin
streptomycin
neomycin
amikacin

Question 5

If patient has gentamicin resistant, gram negative bacilli infection, which aminoglycoside can be given?

Answer 5

Amikacin

Question 6

Which 3 aminoglycosides are active against P. aeruginosa ?

Answer 6

Gentamicin, amikacin, tobramycin

Question 7

In what infection is tobramycin given as inhaler and how long are the course ?

Answer 7

• Chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis
• For 28 days, subsequent courses repeated after 28-day interval without tobramycin nebuliser solution.

Question 8

What to do if a patient missed dose of inhaled tobramycin ?

Answer 8

if a dose is more than 6 hours late, the missed dose should not be taken and the next dose should be taken at the normal time.

Question 9

Which aminoglycoside is parenterally toxic ?

Answer 9

neomycin and it is used for bowel sterilisation

Question 10

Streptomycin is reserved for what infection ?

Answer 10

TB: active against Mycobacterium tuberculosis

Question 11

When gentamicin is given for blind therapy which other antibiotics are also given ?

Answer 11

amoxicillin and metronidazole

Question 12

How should maintenance and loading dose of gentamicin should be calculated ?

Answer 12

on the basis of the patient’s weight and renal function

Question 13

What is the recommended treatment duration of gentamicin ?

Answer 13

7 days

Question 14

A once-daily, high-dose regimen of an aminoglycoside should be avoided in which patient groups ?

Answer 14

patients with endocarditis due to Gram-positive bacteria, HACEK endocarditis, burns of more than 20% of the total body surface area, or creatinine clearance less than 20 mL/minute

Question 15

In which patient aminoglycoside serum concentrations must be determined ?

Answer 15

in the elderly, in obesity, and in cystic fibrosis, or if high doses are being given, or if there is renal impairment.

Question 16

In patients with normal renal function, how should aminoglycoside concentrations be measured ?

Answer 16

after 3 or 4 doses of a multiple daily dose regimen and after a dose change.

Question 17

What is a peak concentration ?

Answer 17

1 hour after dose

Question 18

What is a ‘trough’ concentration ?

Answer 18

measured before next dose, pre-dose

Question 19

If ‘trough’ concentration is high, what action should be taken ?

Answer 19

the interval between doses must be increased.

Question 20

If peak concentration is high, what action should be taken ?

Answer 20

the dose must be decreased

Question 21

Gentamicin, one-hour (‘peak’) serum concentration should be what ?

Answer 21

5–10 mg/litre
Serum-gentamicin concentration should be measured after 3 or 4 doses, then at least every 3 days and after a dose change (more frequently in renal impairment).

Question 22

Gentamicin (‘trough’) concentration should be what ?

Answer 22

less than 2 mg/litre

Question 23

In endocarditis, Gentamicin one-hour (‘peak’) serum concentration should be what ?

Answer 23

3–5 mg/litre

Question 24

In endocarditis, Gentamicin one hour (‘trough’) concentration should be what ?

Answer 24

less than 1 mg/litre

Question 25

How does renal impairment affect gentamicin doses ?

Answer 25

If there is impairment of renal function, the interval between doses must be increased; if the renal impairment is severe, the dose itself should be reduced as well.

Question 26

What are the patient monitoring parameters for aminoglycosides ?

Answer 26

Renal function should be assessed before starting an aminoglycoside and during treatment.

Auditory and vestibular function should also be monitored during treatment.

Question 27

What are the contraindications of aminoglycosides ?

Answer 27

Myasthenia gravis (aminoglycosides may impair neuromuscular transmission)

Question 28

Doctor tells you they are going to put patient on gentamicin, however you are aware that the patient is dehydrated, what advise should you provide to the doctor ?

Answer 28

dehydration should be corrected before starting an aminoglycoside

Question 29

What is the risk of using aminoglycosides in the second and third trimester and which aminoglycosides have lowest and highest risk of causing these risks ?

Answer 29

risk of auditory or vestibular nerve damage in the infant

The risk is greatest with streptomycin. The risk is probably very small with gentamicin and tobramycin,

Question 30

What are important side effects of aminoglycosides ?

Answer 30

Irriversible Ototoxicity and nephrotoxicity

Question 31

Which concomitant nephrotoxic drugs should be avoided with gentamicin ?

Answer 31

ciclosporin, tacrolimus, vancomycin

Question 32

Because aminoglycoside can cause irreversible ototoxicity, what counselling advice should you give to the patient ?

Answer 32

report hearing loss, tinnitus, vertigo (dizziness)

Question 33

Which drugs should not be given together with aminoglycosides due to increased risk of ototoxicity ?

Answer 33

loop diuretics, cisplatin

Question 34

If the Dr decides that patient should still be on loop diuretics while taking aminoglycosides, what advise should you provide in order to minimise the risk of ototoxicity ?

Answer 34

separate by long period as possible

Question 35

What are other side effects of aminoglycosides apart from ototoxicity and nephrotoxicity ?

Answer 35

• peripheral neuropathy
• impaired neuromuscular transmission
• electrolytes: hypoK, Ca and Mg

Question 36

What is MHRA advice regarding some batches of aminoglycosides ?

Answer 36

potential for histamine related adverse drug reactions
monitor patients for signs of histamine related reactions
take caution if concomitant drugs known to cause histamine release are given as well as caution in children, and severe renal impairment