In monitoring vancomycin levels, what is the trough level drawn to determine?

The trough level of vancomycin is measured to determine the lowest concentration of the drug in the bloodstream just before the next dose is administered. This is crucial in ensuring that the drug stays within a therapeutic range, which is effective in treating the infection while minimizing the risk of toxicity.

Therapeutic drug monitoring, especially for vancomycin, aims to keep drug levels within an optimal range that provides efficacy against bacteria without causing adverse effects. If the trough level is too low, the drug may not be effective enough to combat the infection; conversely, if it is too high, there may be a risk of toxicity, particularly to the kidneys.

The other options refer to different concepts altogether. Measuring the highest toxic level would be more relevant to peak levels rather than trough levels. The average level in the bloodstream does not pertain specifically to trough measurements, which are time-point specific. Lastly, total elimination time isn’t directly related to trough measurement, as troughs are focused on the concentration just prior to dosing rather than the time it takes for the drug to be completely cleared from the body.