There are some medications that we give our patients that require close monitoring through testing the blood for levels of the drug. The goal is to make sure the drug is at therapeutic levels in the system so that it produces the optimum effect with minimal side effects. This also applies to some drugs that can cause toxicity at higher levels. For drugs like Vancomycin, we draw these drug levels with what we call a trough level. This means we draw the blood right before a dose is due. The provider or pharmacist will tell you which dose to draw a trough before. Others, like digoxin, lithium, and phenytoin, are drawn at specific intervals after the medication is started. These timings are based on the half-life of the drug, so it’s important that you draw the level at the time it is ordered. If you notice results that show a drug is non-therapeutic (below range) or supratherapeutic (above range), notify the provider immediately.
Date Published - Jul 26, 2018
Date Modified - May 22, 2018