Medicine monitoring

Medicine monitoring measures the level of a medicine in the blood. This makes sure the dose of medicine is correct and that it is producing the desired effect (therapeutic level). Figuring out the correct dosage of a medicine for each person can be hard, because the dose needed to produce a therapeutic level in the blood varies from person to person.

Many things affect medicine level in the blood. These include age, weight, and activity level. Also, medicine level is affected by the speed at which the body breaks down the medicine, the way the medicine was taken (such as by mouth, patch, or shot), and the 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).

Current as of: May 1, 2026

Author: WebMD Ignite Staff

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