What Are Drug Levels

Definition. Therapeutic drug levels are lab tests to look for the amount of a drug in the blood.

How are drug levels measured?

Clinicians routinely monitor drug pharmacodynamics by directly measuring the physiological indices of therapeutic responses, such as lipid concentrations, blood glucose, blood pressure, and clotting. For many drugs, either no measure of effect is readily available, or the method is insufficiently sensitive [24].

What is trough and peak 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.