Medicine monitoring

Medicine monitoring measures the level of a medicine in the blood to make sure the dosage of medicine is correct and that it is producing the desired effect (therapeutic level). Determining the correct dosage of a medicine for each person can be difficult, since the dose needed to produce a therapeutic level in the blood varies from person to person.

Factors that affect medicine levels in the blood include age, weight, activity level, the speed at which the body breaks down the medicine, how the medicine was taken (by mouth, patch, or shot), and other medicines a person is using. Sometimes the amount of medicine that helps (therapeutic level) is very close to the amount that can cause harm (toxic level).