Trough level

In medicine, a trough level is the lowest level that a medicine is present in the body. In a medicine that is administered periodically, the trough level should be measured just before the administration of the next dose in order to avoid overdosing. It should be contrasted with a "peak level", which is the highest level of the medicine in the body, and the "average level", which is the mean level over time. It helps in therapeutic drug monitoring. It's widely used in clinical trials for newer medicines for its therapeutic effectiveness and safety.