Therapeutic Drug Levels

What do Abnormal Results Mean?

Following are some of the drugs that are commonly checked, and their toxic levels:

• acetaminophen: greater than 250 mcg/ml
• amikacin: greater than 25 mcg/ml
• aminophylline: greater than 20 mcg/ml
• amitriptyline: greater than 500 ng/ml
• carbamazepine: greater than 12 mcg/ml
• chloramphenicol: greater than 25 mcg/ml
• desipramine: greater than 500 ng/ml
• digitoxin: greater than 25 ng/ml
• digoxin: greater than 2.4 ng/ml
• disopyramide: greater than 5 mcg/ml
• ethosuximide: greater than 100 mcg/ml
• flecainide: greater than 1.0 mcg/ml
• gentamicin: greater than 12 mcg/ml
• imipramine: greater than 500 ng/ml
• kanamycin: greater than 35 mcg/ml
• lidocaine: greater than 5 mcg/ml
• lithium: greater than 2.0 mEq/L
• methotrexate: greater than 10 mcmol over 24-hours
• nortriptyline: greater than 500 ng/ml
• phenobarbital: greater than 40 mcg/ml
• phenytoin: greater than 30 mcg/ml
• primidone: greater than 15 mcg/ml
• procainamide: greater than 16 mcg/ml
• propranolol: greater than 150 ng/ml
• quinidine: greater than 10 mcg/ml
• salicylate: greater than 300 mcg/ml
• theophylline: greater than 20 mcg/ml
• tobramycin: greater than 12 mcg/ml
• valproic acid: greater than 100 mcg/ml

• mcg/ml = microgram per milliliter
• ng/ml = nanogram per milliliter
• mEq/L = milliequivalents per liter
• mcmol = micromole