Peaks and Troughs

How to Subscribe
MLS & MLT Comprehensive CE Package
Includes 176 CE courses, most popular
$109Add to cart
Pick Your Courses
Up to 8 CE hours
$55Add to cart
Phlebotomy CE Package$59Add to cart
Individual course$25Add to cart
Need multiple seats for your university or lab? Get a quote
The page below is a sample from the LabCE course Special Topics in Phlebotomy. Access the complete course and earn ASCLS P.A.C.E.-approved continuing education credits by subscribing online.

Learn more about Special Topics in Phlebotomy (online CE course)
Peaks and Troughs

As the prescribed drug is used or metabolized by the body, the drug level decreases. 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.
To assess peak levels, the time for drawing depends on the route of administration:
  • Intravenous (IV): 15 - 30 minutes after injection/infusion
  • Intramuscular (IM): 30 minutes - one hour after injection
  • Oral: One hour after drug is taken (assumes a half-life of > two hours)