Aminoglycosides Flashcards
(15 cards)
Aminoglycosides Examples?
Amikacin
Gentamicin
Neomycin
Streptomycin
Tobramycin
Key points about aminoglycosides
- All bacteriocidal and are active against some gram positive and many gram negative organisms
- Broad spectrum antibiotics
- TAG- Tobramycin,Amikacin and Gentamicin are active agents against pseudomonas aeruginosa ( which causes pneumonia)
- Streotomycin is active against mycobacterium tuberculosis (reserved almost entirely for tuberculosis)
- Not given orally( not absorbed from the gut) therefore must be given by injections for systemic infections
- Gentamicin is the most common aminoglycoside in the UK
- Used to treat serious infections (eye,ear,diabetic foot, endocarditis, septicaemia,meningitis and other CNS infections and pneumonia)
Common side effects of aminogylcosides
- Dose related ( because it has a narrow therapeutic index)
- Parenteral treatment should not exceed 7 days wherever possible
- renally excreted so minor or renal function and care with elderly patients
- signs of Ototoxicity
- Nephrotoxicity - occurs mostly in patients with renal impairment
- risk in pregnancy - auditory damage in infants
What are Ototoxicity signs
- Tinnitus or ringing in ears
- Hearing loss
- Dizziness
- Uncoordination in movement
Nephrotoxicity
- decreased urine output
- SOB
- Fluid retention( swelling in legs,ankles and feet)
- Fatigue
Important interactions of aminoglycosides
- Ototoxicity with diuretics
- Nephrotoxicity with cephalosporins, vancomycin or ciclosporin
Dose adjustment for aminoglycosides
- if renal impairment - increase dose interval
- if renal impairment is severe, reduce dose
Monitoring requirements
- plasma concentration
- renal function
- auditory and vestibular function
Specific monitoring
- serum concentration should be monitored in patients receiving parenteral aminoglycosides
- Monitored in elderly, obese,cystic fibrosis, renal impairment and higher doses
- Take blood samples approximately an hour after administration (peak concentration) and also just before next dose(trough)
- if pre dose is too high (trough) then increase the dosing interval
- if post dose is too high, decrease the dose, if within range then maintain the dose. If below the range then increase the dose
Gentamicin - For endocarditis
Monitoring:
1) For IM and IV use for multiple daily regimen
Peak concentration should be = 5-10 mg/l
Trough concentration should be = Less than 2 mg/L
2) For multiple daily dose regimen in endocarditis
Peak concentration should be between = 3-5 mg/L
Trough concentration should be less than 1 mg/L
Amikacin
Is more stable to enzyme inactivation than gentamicin and used for gentamicin resistant bacteria
Neomycin sulfate
Too toxic for parenteral admin
Tobramycin
Administered by nebuliser or inhaler
Side effects of gentamicin
- antibiotic associated colitis
- blood disorders
- depression
- neurotoxicity
- vestibular damage
- skin reactions
- tinnitus
- nausea and vomitting
- Nephrotoxicity
MHRA warning
- aminoglycosides increase the risk of deafness (toxicity) in patients that have mitochondrial mutations
- potential for histamine related adverse reactions with some batches, caution with patients on drugs which release histamine eg. Opioids w
