Rational use of drugs increases the effectiveness of treatment by achieving maximum effect and minimal toxicity. Rational treatment is able to manage the disease within the shortest time with the lowest financial cost accompanied minimal adverse drug reactions.
We summarized the selected drug problems arising from the variable individual reactions of patients, accompanied by inadequate therapeutic response, or by the occurrence of adverse drug reactions. To optimize drug therapy, besides choice of drug and dosage, early detection of adverse drug interactions and disturbances of hepatic and renal function are equally important.
The therapeutic drug monitoring is of indirect importance, focusing on quantitative relationships between dose, concentration and effect it increases the quality of pharmacotherapy. Recently, pharmacogenetics methods in pharmacotherapy are applied, describing the relationship between the individual genetic disposition and the effect of drugs used.
We focused in particular on examples of DNA testing, which reveals polymorphic defects in drug metabolizing enzymes. For example frequently performed test thiopurine S-methyltransferase documents the importance of metabolic phenotype for prevention of the toxicity of certain drugs.
The clinical significance of pharmacogenetic tests in oncology is well established for number new drugs. This is an example of individualized choice of treatment of oncological patients.
These findings support the development of highly efficient and targeted diagnostics accompanying therapy that improves patient outcomes and reduces side effects. Therapeutic drug monitoring and pharmacogenetic testing are complementary.