Buxton2 Flashcards
When should you use vancomycin?
Vancomycin is indicated for the treatment of serious or severe infections caused by susceptible strains of methicillin-resistant (beta-lactam-resistant) staphylococci.
Vancomycin is primarily effective against gram-positive cocci. Staphylococcus aureus and Staphylococcus epidermidis, including both methicillin-susceptible (MSSA & MSSE) or resistant-species (MRSA & MRSE), are usually sensitive to vancomycin with minimum inhibiting concentrations (MIC) less than 1.5 mcg/ml. Most strains of streptococcus are sensitive to vancomycin.
What is the mechanism of vancomycin?
it inhibits proper cell wall synthesis in Gram positive bacteria
Describe 2 bad side effects/syndromes that can occur with vancomycin use.
ototoxicity in 2%: associated w/ high peak & trough levels
red man syndrome: upper body rash, hypotension, associated with IV admin that is too fast.
nephrotoxicity possible with really high doses, high trough levels & long duration of use.
Vancomycin when given by IV infusion over 1 hour exhibits characteristics of which compartment model?
2 compartment model
alpha distribution: 2 hours
beta elimination
T/F Vd for vancomycin is highly variable (0.2 – 1.5 L/Kg) making treatment difficult.
True.
Is vancomycin clearance roughly equivalent to creatinine clearance?
Yes.
What are aminoglycosides used to treat?
Aminoglycosides have bactericidal activity against most gram-negative bacteria including Acinetobacter, Citrobacter, Enterobacter, E. Coli, Klebsiella, Proteus, Providencia, Pseudomanas, Salmonella, Serratia and Shigella.
**tobramycin & gentamicin are both aminoglycosides
What are some possible negative side effects with aminoglycosides?
Aminoglycosides are associated with nephrotoxicity and ototoxicity, both of which are associated with elevated trough levels and sustained elevated peak levels.
When patients have ascites or Cystic Fibrosis they have increased ECF…this leads to what changes in Vd of aminoglycosides?
The Vd increases.
How does the elimination rate of aminoglycosides relate to creatinine clearance?
it has a strong linear correlation
What happens to the elimination rate of aminoglycosides when patients have cystic fibrosis? When patients have a major body burn? When patients are in the ICU?
CF: 50% faster elimination
Body Burn: Increased Elimination (faster metabolic rate)
ICU: faster metabolism–elimination of aminoglycosides
Aminoglycosides can cause ototoxicity. What are factors that increase this risk?
Factors associated with otoxicity include increasing age, duration of therapy, elevated peak and trough levels, concurrent loop diuretics or vancomycin, underlying disease states and previous exposure to aminoglycosides.
**also causes bilateral vestibulopathy
The A1555G mutation in the mitochondrial 12S ribosomal RNA gene is associated with what?
an increased risk of ototoxicity if you use aminoglycosides
When aminoglycosides are given by IV infusion over a 30 minute period they exhibit a 3 compartment model. What is the 3rd compartment?
gamma: tissue release–a little released over time. If not released–could cause toxicity after a bunch of accumulation.
What are the factors associated with nephrotoxicity following aminoglycoside use?
Factors associated with nephrotoxicity include duration of treatment, increasing age, compromised renal function, volume depletion, elevated peak and trough levels, concurrent nephrotoxic drugs (NSAIDs, loop diuretics, Vancomycin) and previous exposure to aminoglycosides.
