THE WAYS TO ENHANCE SAFETY OF COMBINATIONS OF DRUGS PROLONGING QT INTERVAL IN THE OUT-PATIENT AND POLYCLINIC PRACTICE

Abstract

Prolongation of QT interval is a predictor of fatal disorders of cardiac rhythm and sudden death. Side effects of medications is one of the main causes of prolonged QT interval. In the clinical practice, drugs with potential and conventional risks of QT interval prolongation are combined. Threats of such a combination can be amplified if there is a potential of the drugs' interaction on the metabolic level. Materials and methods. In order to detect cases of drug-induced QT interval prolongation, 935 medical files of patients registered at the municipal polyclinic were analyzed. The website of drugs.com was used to categorize clinical significance of interaction between drugs. Results. In a municipal polyclinic, pharmacotherapy of those with coronary disease is administered without consideration of predicted drug interaction, related to changes in the activity of isoenzymes of cytochrome P450. The prescription of clinically significant potentially dangerous combination of amiodarone + torasemide makes 13.3% out of a total number of drug combinations, causing prolongation of QT interval. The potential mechanism of interaction between amiodarone and torasemide, providing impact on QT interval prolongation on the metabolic level is a competition of substrates on the level of CYP 2C8 and the result of CYP 2C9 inhibiting by amiodarone. Conclusion: The potential to predict the prolongation of QT interval resulting from drug interaction and replacement of drugs in such combinations with some other will allow enhancing the safety of combined pharmacotherapy with drugs with potential and conventional risks of QT interval prolongation.

Keywords

• safety
• qt interval
• ventricular cardiac rhythm disorders
• sudden death
• drug interaction
• cytochrome p450