P.3. Basic Science, Sudden Death Risk Stratification and Ventricular Arrhythmias: P.3.2 The Analysis of Pharmacological Effects on Ionic Currents

In connection with that antiarrhythmic drugs blocking voltage dependent Na-channels frequently possess arrhythmic effect, in clinic the drugs influencing on K-channels are used more often. Amiodarone (Cordaron, Sanofi) and sotalol (Sotahexal, Hexal) are the drugs most frequently used all over the world. Hydroxyzine hydrochloride (Atarax, USB-Pharma) is a tranquilizer, however, it has been noticed that it helps to reduce an accompanying arrhythmia.

The single-pipette, whole-cell neuron, voltage-clamp technique was used for recording membrane currents. The measurement was started after superfusion with solution of amiodarone, sotalol and hydroxyzine hydrochloride in concentration: 1, 10, 100 and 1000 mkmol/L.

Amiodarone renders active on slow K currents (Iks) biphase action. Under influence of a drug in low concentration there is an increase in an ionic currents, and suppression begins with concentration 100 mkmol/L, reaching 56% at action in concentration 1000 mkmol/L. Sotalol in a range of action of concentration from 1 up to 500-700 mkmol/L tended to increase slow K current and in concentration 1000 mkmol/L authentically reduced it almost on 12%. Under influence of hydroxyzin hydrochloride there is only a suppression of an ion current down to 1000 mkmol/L full at concentration.

At action amiodarone restoration of a current after washing up of a drug occured up to 82% from the initial level. Restoration of an ionic current after action sotalol occured slowly (for 5-7 min) and only up to 90% from the initial level. Under influence of hydroxyzine hydrochloride convertibility of K currents suppression is small: in 15 minutes of washing up of all up to 35% from the initial level.

Sotalol has less expressed membrane action, and its effect at action in low concentration, most likely, is caused by known beta-blocking action, and in higher concentration - membrane action is possible. Hydroxyzine hydrochloride possesses an expressed action on Iks that specifies an opportunity of its application for cardiological patients, and detection of this effect demands further investigation.