Smith

Question 1

What are the 3 main aminoglycosides

Answer 1

gentamicin

tobramycin

amikacin

Question 2

Adverse reactions of aminoglycosides

Answer 2

• Nephrotoxicity
  
  • begins several days after therapy started or after meds are stopped
  • first sign = INCREASE SERUM CREATININE
  • usually reversible
  • increased risk when used with VANCOMYCIN
• ototoxicity
  
  • IRREVERSIBLE
  • manifest as auditory toxicity = tinnitus, loss of acuity, feeling of fullness in ears
  • manfiest as vestibular toxicity = dizziness and nausea, poor balance
• neuromuscular blockade = inhibits acetylcholine release and paralysis results
  
  • USUALLY DUE TO RAPID ADMIN VIA IV BOLUS
    
    • need to be infused over 30 mins

Question 3

Dose and admin of aminoglycosides

Answer 3

• ALL parenteral, not absorbed in stomach
• correlation between dosing and side effects
• REQUIRES LOADING DOSE regardless of renal function
  
  • Gentamicin and tobramycin (2mg/kg)
  • Amikacin (7.5mg/kg)
• MAINTENANCE dose is calculated based on renal function
  
  • NORMAL renal function
    
    • Gentamicin and tobramycin = 3-5mg/kg/day q8-12h
    • Amikacin 15mg/kg/day q12h

Question 4

Cockcroft and gault*********

Answer 4

Creatinine clearance =

(140-age) X weight (kg) / (Serum creatinine X 72)

Women = X.85

Question 5

Aminoglycosides PEAK AND TROUGHS

Answer 5

• used to dtermine blood levels
• usually drawn after third dose
• PEAK drawn immediately after dose
  
  • peak is dose dependent
• Trough drawn 20-30 minutes BEFORE next dose
  
  • trough is TIME dependent

Question 6

Describe the next dose based on the values of PEAK AND TROUGH

Answer 6

• peak HIGH and trough NORMAL = DECREASE dose
• peak LOW and trough NORMAL = INCREASE dose
  
  • Peak = Dose = right after antibiotic is given
• Peak NORMAL and trough HIGH = INCREASE TIME
• Peak NORMAL and trough LOW = DECREASE TIME
  
  • Trough = time = right before antibiotic is given

Question 7

Post-op fever worries

Answer 7

• benign post-op fever (normal right after surgery)
• Wind = pneumonia (1 day post surgery)
• Water = UTI (2day post surgery)
• Wound = Post-op infection (3rd day post surgery)
• Walk = DVT (4th day post surgery)
• Wonder = wondering why they have a fever (often drug rxn) (5th day post surgery)

Question 8

Radiographic contrast agents and ARF

Answer 8

• increases plasma volume
• osmotic diuresis
• increases in uric acid and oxalate excretion
• ARF can occur in 24-48h after diuresis in some pts after a contrast study
• creatinine peaks 3-5 days and returns to normal in 10-14 days

Question 9

Contrast induced ARF risk FACTORS

Answer 9

• Definite risk factors
  
  • pre-existing insufficiency
  • diabetes mellitus
• Probable risk factors
  
  • dehydration
  • prior contrast induced ARF
• Possible risk factors
  
  • large contrast load
  • advanced age
  • CHF
  • vascular disease
  • proteinuria
  • hyperuricemia

Question 10

TX/prevention of contrast induced ARF

Answer 10

• Tx is unsuccessful in pts who develop ARF
• Emphasis placed on prevention
  
  • Identify patient at risk
  • avoid study if feasible
  • hydrate –> does not really prevent, but may minimize severity
  • minimize contrast load
  • avoid repeated studies