[Study of the relations between prazosin administration schedule for patients with subacute myocardial infarction and the type of central hemodynamics based on pharmacokinetic data]. / Zavisimost' rezhima naznacheniia prazozina bol'nym podostrym infarktom miokarda ot tipa ikh tsentral'noi gemodinamiki na osnove farmakokineticheskikh dannykh.

The model-independent pharmacokinetics and hemodynamics were studied in 48 patients (35 males and 13 females; mean age, 60.0 +/- 1.3 years) with primary myocardial infarction of various sites. After a single dose of 2-5 mg prazosin, the mean prazosin molecule retention time, systemic clearance and distribution were found to be substantially different from those in the groups formed by the central hemodynamic types recorded before the drug administration. The interval between the maintenance doses was recommended to be 8 hours for the hypokinetic type, 7 hours for the hypovolemic type and 6 hours for the congestive and eukinetic types. In the models with "saturated" effects it was calculated that the optimal therapeutic effect of prazosin in patients with myocardial infarction was seen in the plasma concentration range of 50-80-100 ng/ml, whose attainment required its single dose of 3-5 mg 3-4 times a day during its course monotherapy.

[Prazosin pharmacodynamics and pharmacokinetics in patients with myocardial infarct complicated by heart failure in the subacute period]. / Farmakodinamika i farmakokinetika prazozina u bol'nykh infarktom miokarda, oslozhnennym v podostrom periode serdechnoi nedostatochnost'iu.

Central hemodynamic parameters were monitored by invasive procedures (pulmonary arterial catheterization), and prazosin kinetics following the administration of a single 5 mg dose were determined in 69 patients with subacute myocardial infarction, complicated by heart failure. The response to prazosin was dependent on pretreatment hemodynamic parameters and differed between patients with early and manifest heart failure. There was a correlation between the peaks of hemodynamic change and drug concentration.

[The pharmacokinetics and the concentration-and-effect relationship of prazosin in patients at the beginning of the subacute period of myocardial infarct complicated by the development of heart failure]. / Farmakokinetika i vzaimosviaz' kontsentratsii i éffekta prazozina u bol'nykh v nachale podostrogo perioda infarkta miokarda, oslozhnennogo razvitiem serdechnoi nedostatochnosti.

The pharmacokinetics of prazosin was studied in 16 patients in the early subacute period of myocardial infarction complicated with heart failure following a single and 10-day administration. The increase of the half-life of the drug (6.6 +/- 1.6 h) and the elevation of the blood plasma concentration 1-2.5 h after administration (87 +/- 33 ng/ml) were found. After 10-day administration the increase of the apparent total clearance of the drug was established. The blood plasma levels of prazosin significantly correlated with the change of the hemodynamic parameters measured invasively after a single administration of 2-5 mg of the drug. After 10 days of treatment the correlation weakened and the regression line angle reduced that reflected the development of tolerance to the drug. On the basis of the calculated effective concentrations, there were determined the optimal intervals of the drug dosage.