Therapeutic drug monitoring (TDM) is a department of clinical chemistry and clinical pharmacology that specializes in measuring drug concentrations in the blood. The main focus here is on drug preparations with a narrow therapeutic “window”. TDM improves patient care by correction of drug doses.
There are many factors affecting the results of the drug concentration: time of drugs delivery, pathway, dosage form, blood samples collection and processing, storage conditions, sensitivity and accuracy of the analytical method, the pharmacokinetics of drugs and their effects on each other.
Failure to comply with any of the components seriously reduces the effect of the drug concentration used to optimize treatment. Therefore, the organized approach to the common process is important.
A priori therapeutic drug monitoring
A priori TDM is determining the first dose regimen given to a patient.
A posteriori therapeutic drug monitoring
Preanalitic, analytical, post-analytic stages are based on accurate and timely detection of active or toxic forms of the drug in the biological samples collected at appropriate times.
Indications for Therapeutic Drug Monitoring are as follows:
- Relationship between drug concentration and pharmacological effects in plasma;
- Narcotic drug management;
- Drugs with a narrow therapeutic “window”;
- Patient’s drug compatibility problem;
- The drug dose cannot be optimized only with clinical observation
Analyzed drug samples by therapeutic monitoring:
- Aminoglycosides (gentamicin);
- Antiepileptics (carbamazepine, phenytoin and valproic acid);
- Antidepressant stabilizers (especially lithium citrate);
- Antipsychotic drugs (pimazide and clozapine);
- Immunosuppressive agents (cyclosporine, tacrolimus);
- Biological monoclonal antibodies (such as adalimumab, certolizumab pegol and infliximab);
- Cannabinoids (marijuana), opiates (morphine, codeine, tebain, heroin)