Commonly Monitored Drugs


This class of drugs, also known as anticonvulsants, is most often prescribed for the management of epilepsy, though some drugs may also be prescribed for other indications such as tic douloureux, myotonia, bipolar effective disorder, prophylaxis of certain varieties of migraine and of cardiac dysrhythmia. All antiepileptic drugs are capable of depressing abnormal neuronal discharges in the central nervous system, which may otherwise result in seizures. Other drugs in this category, such as clonazepam and sulthiame, do not require monitoring.

  • Carbamazepine
  • Phenobarbital
  • Phenytoin
  • Valproic Acid


Arrhythmia is a disorder that may result in cardiac abnormalities. They are classified as either tachycardia (fast heartbeat, > 100 bpm) or bradycardia (slow heart beat, < 60 bpm). Antiarrhythmic agents are used to control the rate and rhythm of the heart beat. This class of drugs is segregated into four subclasses based on the action of the drug. Many of the drugs in class I require frequent monitoring, and are therefore being displaced by the class II and III drugs, which require less monitoring.

  • Digitoxin
  • Digoxin
  • Lidocaine
  • NAPA
  • Procainamide


Most of the drugs in this class have wide therapeutic ranges and therefore do not require therapeutic monitoring. However, those with narrow therapeutic ranges require monitoring to avoid potentially irreversible toxicity. Still others are monitored on a case-by-case basis. Gentamicin and tobramycin are aminoglycoside antibiotics most commonly used for infections by resistant gram-negative organisms. Vancomycin is glycopeptide antibiotic used to treat life-threatening infections caused by gram-positive cocci. Due to the emergence of vancomycin-resistant organisms, it has been recommended that its use be restricted to treating methicillin-resistant Staphylococcus aureus and ampicillin-resistant enterococcal infections.

  • Gentamicin
  • Tobramycin
  • Vancomycin


Used to treat bipolar disorders or mania associated with other affective disorders.

  • Lithium


Theophylline is one of the most commonly used bronchodilators. It is primarily used to treat patients with chronic asthma. Monitoring is necessary due to the drug’s highly variable inter-individual pharmacokinetics.

  • Theophylline


TDM testing is a critical aspect of immunosuppressive drug therapy. Optimizing drug dosing is not only key to avoiding rejection, but also in reducing the severe side effects of these drugs (infections, cancer, weight gain, hypertension, and possible liver or kidney failure), which often prompt patient non-compliance. The strategy is to employ a combination of drugs in doses that prevent acute rejection and loss of graft function without compromising overall health. Transplant patients are prescribed immunosuppressive drugs as lifelong maintenance therapy and most drugs are routinely monitored.

  • Cyclosporine
  • Mycophenolic Acid
  • Sirolimus
  • Tacrolimus

More information on ISD testing