Therapeutic drug levels

A blood sample is needed. Most of the time, blood is drawn from a vein located on the inside of the elbow or the back of the hand.

You will need to prepare for some drug level tests. Your health care provider will tell you if you need to change the times you take any of your medicines. DO NOT stop or change your medicines without talking to your provider first.

You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.

With most medicines, you need a certain level of the drug in your blood to get the proper effect. Some medicines are harmful if the level rises too high and do not work if the levels are too low. Monitoring the amount of the drug found in your blood allows your provider to make sure the drug levels are in the proper…

Following are some of the drugs that are commonly checked and the normal target levels: Acetaminophen: varies with use Amikacin: 15 to 25 mcg/mL (25.62 to 42.70 micromol/L) Amitriptyline: 120 to 150 ng/mL (432.60 to 540.75 nmol/L) Carbamazepine: 5 to 12 mcg/mL (21.16 to 50.80 micromol/L) Cyclosporine: 100 to 400 ng/mL…

Values outside the target range may be due to minor changes or be a sign that you need to adjust your dosages. Your provider may tell you to skip a dose if the values measured are too high. Following are toxic levels for some of the drugs that are commonly checked: Acetaminophen: greater than 250 mcg/mL (1653.50…

Bluth MH, Pincus MR, Abraham NZ. Toxicology and therapeutic drug monitoring. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 24. Clarke W. Overview of therapeutic drug monitoring. In: Clarke W, Dasgupta A, eds. Clinical…