Therapeutic Drug Monitoring Lecture 5: Vancomycin

1. Treat severe gram-positive infections due to organisms resistant to other antibiotics, such as methicillin-resistant staphylococci and ampicillin-resistant enterococci. 2) Treat infections caused by other sensitive gram-positive organisms in patients allergic to penicillins.

Vancomycin is bactericidal and exhibits time-dependent or concentration-independent bacterial killing, meaning it kills bacteria most effectively when drug concentrations are 3-5 times the minimum inhibitory concentration (MIC) for the bacteria.

Vancomycin is administered as a short-term (1-1.5 hour) intravenous infusion. A peak vancomycin concentration is obtained after 1.5 hours, after allowing a 0.5-1 hour waiting period for distribution to finish before measuring the peak.

<p>A 0.5-1 hour waiting period is allowed before measuring peak vancomycin concentrations because vancomycin exhibits a distribution phase, where the drug in the blood and tissues are not yet in equilibrium.</p> Signup and view all the answers

<p>Vancomycin's time-dependent or concentration-independent bacterial killing means it is most effective at killing bacteria when its concentrations are 3-5 times the minimum inhibitory concentration (MIC) for the bacteria.</p> Signup and view all the answers

<p>Vancomycin is used to treat methicillin-resistant staphylococci and ampicillin-resistant enterococci.</p> Signup and view all the answers

<p>Vancomycin is used to treat gram-positive infections in patients allergic to penicillins because it is an alternative antibiotic option for these patients.</p> Signup and view all the answers

<p>Vancomycin's bactericidal activity means it kills bacteria, rather than just inhibiting their growth.</p> Signup and view all the answers

<p>2 hours or longer</p> Signup and view all the answers

<p>Vancomycin is almost completely eliminated unchanged in the urine primarily by glomerular filtration (≥90%).</p> Signup and view all the answers

<p>20-40 μg/mL</p> Signup and view all the answers

<p>Clinicians should consider measuring peak concentrations when large doses are given (&gt;1500 mg/dose) or for infections that require high peak concentrations (such as central nervous system infections) in order not to have a steady-state peak concentration that would be above the accepted toxic range (&gt;80 μg/mL) in which could developed ototoxicity while receiving vancomycin.</p> Signup and view all the answers

<p>40-60 μg/mL or direct administration into the cerebral spinal fluid</p> Signup and view all the answers

<p>When high vancomycin concentrations are needed for therapeutic reasons, the recommended trough concentration is &gt;15 μg/mL, and the recommended peak concentration is &gt;40 μg/mL.</p> Signup and view all the answers

<p>Ototoxicity can become permanent</p> Signup and view all the answers

<p>Intramuscular administration is usually avoided because this route has been reported to cause tissue necrosis at the site of injection.</p> Signup and view all the answers

<p>Trough concentrations (pre-dose or minimum concentrations)</p> Signup and view all the answers

<p>Because vancomycin follows time-dependent bacterial killing</p> Signup and view all the answers

<p>Vancomycin can cause allergic symptoms such as chills, fever, skin rashes, and anaphylactoid reactions.</p> Signup and view all the answers

<p>Since nephrotoxicity is related to high trough concentrations, measurement of this value should ensure therapeutic, non-nephrotoxic drug concentrations.</p> Signup and view all the answers

<p>3 to 5 times the organism's MIC</p> Signup and view all the answers

<p>Oral bioavailability is poor.</p> Signup and view all the answers

<p>Ototoxicity</p> Signup and view all the answers

<p>When high vancomycin concentrations are needed for therapeutic reasons (trough &gt;15 μg/mL, peak &gt;40 μg/mL), assessment of renal function and auditory/vestibular function should be conducted on a daily basis.</p> Signup and view all the answers

<p>10-15 μg/mL</p> Signup and view all the answers

<p>Due to the presence of MRSA with higher MIC values</p> Signup and view all the answers

<p>Vancomycin penetrates into lung tissue poorly, with an average serum:tissue ratio of 6:1</p> Signup and view all the answers

<p>15-20 μg/mL</p> Signup and view all the answers

<p>Increased incidence of nephrotoxicity</p> Signup and view all the answers

<p>Hypotension or other nephrotoxic drug therapy (such as aminoglycosides, amphotericin B, or immunosuppressants)</p> Signup and view all the answers

<p>Vancomycin is usually considered to have less nephrotoxicity potential than aminoglycoside antibiotics</p> Signup and view all the answers

<p>Vancomycin-related nephrotoxicity is usually reversible with a low incidence of residual damage if the antibiotic is withdrawn or doses appropriately adjusted soon after renal function tests change</p> Signup and view all the answers

<p>A favorable response is indicated by decreasing white blood cell counts toward normal range, the fever curve approaching normal, and resolution of infection site tests/procedures.</p> Signup and view all the answers

<p>Vancomycin steady-state serum concentrations should be measured in 3-5 estimated half-lives, typically after the third dose which is 1-3 days after dosing commenced.</p> Signup and view all the answers

<p>Since vancomycin exhibits time-dependent bacterial killing, its efficacy is most closely related to the minimum serum concentration over the dosing interval.</p> Signup and view all the answers

<p>Current microbiologic cultures, sensitivities, and antibiograms noting pathogen resistance patterns and minimum inhibitory concentrations should be consulted.</p> Signup and view all the answers

<p>With adequate patient monitoring, transient serum creatinine increases of 0.5-2.0 mg/dL may occur as the only result of vancomycin nephrotoxicity.</p> Signup and view all the answers

<p>The trend of the patient's white blood cell count, body temperature (fever curve), and infection site test results are monitored longitudinally to assess response to treatment.</p> Signup and view all the answers

<p>Antibiograms should be consulted regularly to note changes in resistance patterns and minimum inhibitory concentrations for pathogens over time.</p> Signup and view all the answers

<p>Vancomycin exhibits time-dependent bacterial killing, where the minimum serum concentration over the dosing interval is most predictive of efficacy.</p> Signup and view all the answers