The half-life of the drug and the ability of the body to metabolize or excrete the drug determine the trough (lowest) concentration of drug before the next dose. For oral ingestion, rate of absorption and distribution is important. For injection, this depends upon the volume of distribution of the drug. Depending upon the route of administration, a peak (highest) concentration occurs at an interval following administration. Unless a drug is being administered by continuous infusion, there are variations in concentration depending upon dosing intervals. In general, the ideal range between highest and lowest effective and safe level is the therapeutic range of the drug. If the level is too low, then the drug may not have efficacy. The pharmacologic effect of the drug may depend upon achieving a specific concentration. TDM is employed when clinical findings, such as vital signs, or results of other laboratory testing do not indicate whether an optimal drug concentration has been achieved. An underdose or overdose may easily occur and is undesirable. It is desirable that these drug concentrations fall within a narrow therapeutic range. Therapeutic drug monitoring (TDM) is utilized to monitor and adjust drug doses based on measured plasma concentrations. Return to the main menu Therapeutic drug monitoring Laboratory Medicine Curriculum Clinical Laboratory - Chemical Pathology and Immunology
0 Comments
Leave a Reply. |