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 the purpose of a trough level?
In medicine and pharmacology, a trough level or trough concentration (C
trough
) is
the concentration reached by a drug immediately before the next dose is administered
, often used in therapeutic drug monitoring.
When should a trough level 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).
What is a trough blood test?
A trough
level is the lowest concentration reached by a drug before the next dose is administered
. For example, if cyclosporine is given twice a day, a blood sample is usually drawn 12 hours after the last dose, before a new dose is given.
How do you find peak and trough?
To assess drug concentrations during the trough phase, blood should be drawn immediately before the next dose. To assess peak levels, the time for drawing depends on the route of administration:
Oral: One hour after drug is taken
(assumes a half-life of > two hours) IV: 15-30 minutes after injection/infusion.
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.
What the body does to drug?
Pharmacokinetics
, sometimes described as what the body does to a drug, refers to the movement of drug into, through, and out of the body—the time course of its absorption.
Why do we draw peak and trough levels?
A peak drug level is drawn at the time when the medication is being administered and is known to be at the highest level in the bloodstream. A trough level is drawn
when the drug is at its lowest in the bloodstream right before the next dose is given
.
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.
How do you calculate trough levels?
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.
How much blood do you need for a Vanco trough?
VANCOMYCIN TROUGH
Serum or plasma. Specimen required: 2 mL aliquot serum or plasma ;
minimum 0.2 mL
.
What do you do when Vanco trough is high?
If the high trough level appears genuine, use the
vancomycin dose adjustment
calculator to obtain a new dosage regime. Consider omitting dose based on the level: – If vancomycin trough level is 20-25mg/L, give new dosage regime without omitting any doses. Take a level before the 4th new dose.
When do you draw a phenytoin trough?
In these situations of routine monitoring (unlike the emergency situation of breakthrough seizures in scenario two), it is preferable to draw the phenytoin level just prior to the next dose (a trough level) or
at least eight hours after the last dose10,11
.
What does peak and trough mean?
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 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.
What is the peaks and troughs of a wave?
Peak – the highest point above the rest position
. Trough – the lowest point below the rest position. Amplitude – the maximum displacement of a point of a wave from its rest position. Wavelength – distance covered by a full cycle of the wave.
