The article considers clinical and pharmacological approaches to rational pharmacotherapy with direct oral anticoagulants (DOAC). The main issues of the mechanism of action, pharmacodynamics, and interaction of these medicines, as well as adverse reactions and, consequently, risks associated with taking DOAC, and the principles of selecting direct oral anticoagulants are discussed. The materials are presented on the basis of modern data from domestic and foreign literature.

The article considers a clinical case of an adverse drug reaction with simultaneous use of amiodarone and warfarin, manifested by hemorrhagic syndrome. It also provides an overview of data available from domestic and foreign sources regarding the drug interaction of warfarin and amiodarone, as well as the features of pharmacotherapy in elderly patients, including the features of pharmacodynamics in this group of patients. The main result of the presented literature review is the conclusion that doctors in their practice should take into account the possibility of drug interaction and pay attention to this section in the instruction leaflets of medicinal products, especially in the treatment of an elderly patient.

The use of drugs during pregnancy and breastfeeding remains one of the least studied, but important issues in pharmacology today. When choosing medicinal products during pregnancy, one of the crucial principles is to ensure the safety of the embryo and fetus. Among the generally accepted rules aimed at eliminating fetal risk, a decrease in the dosage of the drug to the lower limit of the therapeutic range is usually named. However, one should take into account the changes that occur in the body of a pregnant woman: the body weight and the volume of circulating blood rise, the excretion of drugs is accelerated (the clearance increases), which, on the contrary, requires an increase in the dosages of individual drugs to maintain therapeutic efficacy. Antibacterial drugs (ABD) are the most difficult group of drugs to use, since they require taking into account not only the mechanism of action of drugs, but also the basics of clinical microbiology. ABD occupy a special place in clinical practice, as they are one of the most frequently prescribed classes of drugs.