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 trough and peak levels be drawn for therapeutic drug monitoring?
For peak samples, that would typically be
2 to 3 hours after an oral dose
, 30 to 60 minutes after an intravenous dose, 2 to 4 hours after an intramuscular dose, or 1 to 1.5 hours after an intranasal dose. Trough samples are drawn just before administration of the next scheduled dose.
When should peak and trough levels be drawn for gentamicin?
Patients who require treatment with gentamicin often require monitoring, which includes peak and trough levels. Peak levels are typically evaluated 30 minutes after completion of the infusion.
Trough levels should be drawn immediately before the dose is administered
.
Why do we draw peak and trough levels?
To adequately evaluate the appropriate dosage levels of many drugs, the collection and testing of specimens for trough and peak levels is necessary. 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.
When should trough levels be drawn for vancomycin?
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.
What does peak and trough mean?
The lowest level of the drug in the patient’s body is called the trough level. The peak for a drug is
when the level of the drug in the patient’s body is the highest
. To assess drug concentrations during the trough phase, blood should be drawn immediately before the next dose.
What medications require blood level monitoring?
| Drug Category Drugs | Immunosuppressants Cyclosporine, tacrolimus, sirolimus, mycophenolate mofetil, azathioprine | Anti-cancer drugs Methotrexate, all cytotoxic agents | Psychiatric drugs Lithium, valproic acid, some antidepressants (imipramine, amitriptyline, nortriptyline, doxepin, desipramine) |
|---|
Why would blood levels be closely monitored for a patient being treated with gentamicin?
Serum levels are monitored
to reduce the risk of significant accumulation and nephrotoxicity
. Dose is adjusted according to age and renal function.
What is a normal Vanco trough level?
The reference range for vancomycin trough levels is
5-15 mcg/mL
. The reference range for vancomycin peak levels is 20-40 mcg/mL.
What antibiotics require 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.
When should trough levels be taken?
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).
What is peak to trough ratio?
An important consideration for drugs that treat hypertension. The
ratio of blood pressure lowering by the drug
, at the maximum and minimum blood pressures in a 24-hour period.
How is peak and trough performed?
Based upon dosing intervals, a peak drug
level is measured at a specified time following the last dose
, while a trough level is measured at a specified interval before the next dose. The dose is adjusted to maintain the drug level within defined peak and trough ranges.
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.
How often is Vanco trough 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 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.
