Aminolgycosides Flashcards
How does ahminoglycosides work ?
bind irreversibly to bacterial ribosomes: Active against gram-negative aerobe; P. aeruginosa
- Broad spectrum+ bactericidal
What are the uses of aminoglycosides ?
severe sepsis
pyelonephritis
complicated UTI
endocarditis
Why aminglycosides are given via parenteral injection ?
not absorbed by the gut
Name all aminoglycosides available ?
gentamicin tobramycin streptomycin neomycin amikacin
If patient has gentamicin resistant, gram negative bacilli infection, which aminoglycoside can be given?
Amikacin
Which 3 aminoglycosides are active against P. aeruginosa ?
Gentamicin, amikacin, tobramycin
In what infection is tobramycin given as inhaler and how long are the course ?
- Chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis
- For 28 days, subsequent courses repeated after 28-day interval without tobramycin nebuliser solution.
What to do if a patient missed dose of inhaled tobramycin ?
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.
Which aminoglycoside is parenterally toxic ?
neomycin and it is used for bowel sterilisation
Streptomycin is reserved for what infection ?
TB: active against Mycobacterium tuberculosis
When gentamicin is given for blind therapy which other antibiotics are also given ?
amoxicillin and metronidazole
How should maintenance and loading dose of gentamicin should be calculated ?
on the basis of the patient’s weight and renal function
What is the recommended treatment duration of gentamicin ?
7 days
A once-daily, high-dose regimen of an aminoglycoside should be avoided in which patient groups ?
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
In which patient aminoglycoside serum concentrations must be determined ?
in the elderly, in obesity, and in cystic fibrosis, or if high doses are being given, or if there is renal impairment.
In patients with normal renal function, how should aminoglycoside concentrations be measured ?
after 3 or 4 doses of a multiple daily dose regimen and after a dose change.
What is a peak concentration ?
1 hour after dose
What is a ‘trough’ concentration ?
measured before next dose, pre-dose
If ‘trough’ concentration is high, what action should be taken ?
the interval between doses must be increased.
If peak concentration is high, what action should be taken ?
the dose must be decreased
Gentamicin, one-hour (‘peak’) serum concentration should be what ?
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).
Gentamicin (‘trough’) concentration should be what ?
less than 2 mg/litre
In endocarditis, Gentamicin one-hour (‘peak’) serum concentration should be what ?
3–5 mg/litre
In endocarditis, Gentamicin one hour (‘trough’) concentration should be what ?
less than 1 mg/litre
