Optimal Trough Concentration for Complicated Infections
Vancomycin serum trough concentrations of 15–20 mg/L are recommended
to improve penetration
, increase the probability of obtaining optimal target serum concentrations and improve clinical outcomes.
When should trough levels be drawn?
A trough level is drawn
immediately before the next dose of the drug is administered
. A peak level is drawn 1 to several hours after the drug is administered (depending on the drug).
When should vancomycin trough be drawn?
Trough:
just before 4th dose of a new regimen
(prior to 3rd dose for dosing intervals ≥ 24 hours or changing renal function) – Trough levels should be obtained within 30 minutes before the next scheduled dose. – Weekly vancomycin levels should be obtained for long-term vancomycin use with stable renal function.
How often are vancomycin troughs drawn?
Subsequent trough levels: o With dosage change: trough should be taken at new steady state* as described above. o Once target trough achieved: trough should be taken
every 7-10 days
in hemodynamically stable patients; may need more frequently if hemo-dynamically unstable, renal function changing, or patient is on ...
What is a trough blood level?
The trough level is
the lowest concentration in the patient’s bloodstream
, therefore, the specimen should be collected just prior to administration of the drug. The peak level is the highest concentration of a drug in the patient’s bloodstream.
What is peak and trough used for?
The highest and lowest concentrations of a drug in plasma. Measurement of peak and trough drug levels are used
to determine whether an intravenously administered medication is consistently within therapeutic range
.
Why would vancomycin trough be low?
Vancomycin trough concentrations below 10 μg/mL are
associated with inadequate therapy
and an increased risk of developing bacterial resistance. Vancomycin trough concentrations above the therapeutic range may increase the risk of nephrotoxicity.
What do I do if my vancomycin trough is low?
Vancomycin level should be obtained 24 hours after the first dose is given. The patient can be re-prescribed a stat dose when the vancomycin trough concentration is below
20mg/L
. Seek specialist advice from renal/ antibiotic pharmacists for patients with end stage kidney disease and/or dialysis.
What are the adverse effects of vancomycin?
-
Black, tarry stools.
-
blood in the urine or stools.
-
continuing ringing or buzzing or other unexplained noise in the ears.
-
cough or hoarseness.
-
dizziness or lightheadedness.
-
feeling of fullness in the ears.
-
fever with or without chills.
-
general feeling of tiredness or weakness.
How fast does vancomycin work?
Clinical resolution occurred at day 10, which was, on average, only
4 days after the escalation
dose. There were 14 patients in the high-dose group treated with vancomycin 500 mg for the entire therapy course; for these patients, clinical resolution occurred after 5 days on average.
When do you draw vancomycin trough after hemodialysis?
Generally, most people wait
4-6 hours after the end of dialysis
before checking post-HD vancomycin levels to avoid falsely low results.
When do you load vancomycin?
Why administer a vancomycin loading dose? Due to the pharmacokinetics of vancomycin, a loading dose – a large dose given
once at the onset of therapy
to rapidly achieve a therapeutic drug concentration in the body – is required to ensure that vancomycin levels are not subtherapeutic at the beginning of treatment.
What is a normal trough level?
An acceptable trough is
< 10 mg/mL
. Peak levels are not necessary for patients being treated with a course of antibiotics without an identified organism. If obtained, an acceptable peak is 20 – 40 mg/mL and should be obtained 30 minutes after the infusion.
How do you calculate a trough?
To increase the therapeutic utility of an early vancomycin trough concentration, an estimate of the true trough can be determined by
extrapolating the measured value using e
− Kt
, where K = CrCl × 0.00083 + 0.0044 and t is the time difference in hours.
What are trough values?
• Trough concentration:
the concentration of drug in the blood immediately before the next dose is administered
, although this does not necessarily represent the lowest concentration during a dosing interval. • Minimum concentration (C
min
): the lowest concentration of drug in the blood following the administered dose.
What antibiotics need a peak and trough?
-
Antibiotics that Require Frequent Monitoring (Aminoglycosides)
-
35 mcg/ml Peaks 5 mcg/ml Troughs Amikacin Drugs.
-
10 mcg/ml Peaks 2 mcg/ml Troughs Gentamicin Drugs.
-
35 mcg/ml Peaks 5 mcg/ml Troughs Kanamycin Drugs.
-
16 mcg/ml Peaks 2 mcg/ml Troughs Neomycin Drugs.
