Therapeutic drugs are used to heal, control, or prevent certain diseases and conditions, and are often required throughout a person’s lifetime to treat chronic conditions.
Most therapeutic drugs have a narrow therapeutic index and require regular monitoring to ensure correct levels of the drug in the blood are maintained. Therapeutic index refers to the difference in the amount that causes a therapeutic effect, and the amount that causes toxicity.
Toxic levels may occur as a result of a person’s ability to absorb the drug i.e. change in health, additional medication that may be reacting with the drug, and, overdose. In addition, sub-therapeutic levels may occur where the patient’s level of the drug is inadequate for their treatment.
Therapeutic drugs which may require monitoring include:
Monitoring Dosage is Key
Therapeutic drugs are monitored upon initial dosage to evaluate dosage suitability for the individual, as each person absorbs, metabolises and eliminates drugs at different rates. Depending upon test results, drug dosage may be increased or decreased, and monitored until the blood level reaches the therapeutic range.
Testing may be required in situations where a patient is experiencing side effects to determine if the dose needs to be adjusted; if a patient has experienced a change in health i.e. kidney function, thyroid problems, cancer, or stomach or intestinal issues; if a patient begins taking another medication; if a doctor suspects the patient is not taking the recommended dose of medication; and, if an overdose is suspected.