[The relationship between the isosorbide-5-mononitrate concentration and its antianginal effect following the administration of regular and prolonged-action drug forms in patients with stenocardia of effort].

Isosorbide-5-mononitrate (IMN) concentration-antianginal effect relationships were studied in 14 coronary heart diseases patients with stable exertion-induced angina after administration of Efox (Schwarz-Pharma) as two dosage forms: routinely acting tablets (20 mg) and long-acting capsules (50 mg). The antianginal effect index was an increase of treadmill exercise duration (sec) as compared with placebo, the concentration and effect were measured in points 0, 1, 3, and 7 hours after administration, in some patients, investigations were conducted 12 and 24 hours. The two formulations were found to be highly effective drugs whose action lasted 7 hours, by that time the effect of the tablets substantially decreased, which was associated with decreases in drug concentrations. The efficiency of the capsules at this point was significantly higher than that of the tablets. The use of the capsules resulted in tachyphylaxis--rapid decreasing responses to IMN. Following 7 hours of their administration there is a significant decrease in their effect with an increase in IMN concentrations.