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The effectiveness of hypotensive action and tolerance of Isoptin SR-240 were studied in 20 patients with primary arterial hypertension. The drug was used in doses 240-360 mg daily (mean dose 324 mg daily). Blood pressure returned to normal values in 12 (60%) out of 20 patients. In the remaining eight cases no blood pressure normalization was achieved. Side effects occurred in five patients. General worsening of wellbeing and easy tiring were most frequently observed. The results of the present work indicate that Isoptin SR-240 is an effective hypotensive drug, useful in the treatment of mild and moderate arterial hypertension.

Ketanserin, a serotonin-2-receptor antagonist, was administered to 16 patients with mild to moderate essential hypertension in randomized single-blind placebo controlled study. After 2 weeks of placebo administration ketanserin 60 mg daily was given for 3 weeks. In 7 patients the normalization of blood pressure was obtained and they were given the same daily dose of ketanserin for another 3 weeks. In the remaining 9 patients the dose of ketanserin was increased to 120 mg daily for the same period; in one additional case blood pressure decreased to normal. In the whole group the decrease of diastolic pressure was statistically significant comparing to placebo period. Ketanserin therapy did not influence serum free serotonin concentration, but the hypotensive effect was greater in patients with lower serotonin blood levels. Serum aldosterone concentration decreased in the initial period of treatment; the decrease was more pronounced in patients who responded to therapy. In this subgroup of patients diastolic blood pressure correlated positively with plasma renin activity. Ketanserin lowered serum adrenaline concentration, particularly in patients with good response to therapy. There was also decrease of total cholesterol concentration without any significant changes in HDL--cholesterol fraction. The authors conclude that oral chronic ketanserin treatment is an effective therapy in essential hypertension and that its effectiveness is greater in patients with lower serum serotonin levels. The hypotensive effect of the drug may be connected with lower sympathetic activity and with changes in renin-angiotensin-aldosterone system. Ketanserin is well tolerated and exerts beneficial effect on lipid metabolism.

An effect of the long-term prazosin therapy on sympathetic activity, renin plasma activity and beta-endorphin and lipid blood levels was investigated in 23 patients with the primary arterial blood hypertension. Group A included 18 patients treated with prazosin, and group B - 5 patients treated with prazosin combined with propranolol. Mean daily dose of prazosin in group A was 3.0-10.0 +/- 1.3 mg in different phases of therapy whereas in group B mean daily dose of prazosin was 3.0-6.5 +/- 1.8 mg and propranolol 50-80 mg. Significant decrease in diastolic and systolic blood pressure (p < 0.01) was achieved in both groups. Additionally significant decrease in pulse rate (p < 0.01) was seen in group B. It was found that prazosin produced significant increase in plasma noradrenaline in group A and decrease in 4-hydroxy-3-methoxyglycol excretion with the urine (p < 0.05) in both groups. Moreover, negative correlation between a decrease in blood pressure (diastolic) and noradrenaline excretion with the urine (p < 0.05) was noted in group A. No effect of prazosin therapy on plasma renin activity, beta-endorphin and lipids blood levels was observed in both groups. These results suggest that prazosin therapy in patients with the primary blood hypertension exerts an effect on sympathetic activity and does not change plasma renin activity or blood beta-endorphin and lipids levels.

An effect of the treatment with guanfacine on the activity of the adreno-sympathetic system, beta-thromboglobulin, beta-endorphin, and blood lipids was studied in 30 patients with the primary arterial blood hypertension. It was found that guanfacine significantly decreases plasma noradrenaline, adrenaline, and dopamine. Moreover, it decreases the excretion of noradrenaline, adrenaline and 4-hydroxy-3-methoxy-phenylglycol. These effects correlate with the drop in both systolic and diastolic blood pressure. A decrease in plasma renin activity was also observed. It correlated with the blood pressure drops. Guanfacine increased beta-endorphin levels while beta-thromboglobulin, total cholesterol and triglycerides levels remained unaffected. The authors suggest that the hypotensive effect of guanfacine is related to the decrease in adreno-sympathetic system activity and plasma renin activity and no effect on the erythrocyte activity and lipids metabolism.

An effect of enalapril maleate on the activity of renin-angiotensin-aldosterone system and sympathetic reactivity, erythrocyte prostaglandin and sodium levels as well as blood beta-endorphin was investigated in 28 patients with the essential arterial blood hypertension. It was found that enalapril maleate significantly increased plasma renin activity, decreased plasma norepinephrine and its 24-hour excretion, and decreased erythrocyte beta-endorphin and sodium levels. Blood epinephrine and aldosterone levels and their daily excretion remained unchanged similarly to prostaglandins. The above results suggest that a decrease in sympathetic system activity and intracellular sodium concentration may play a role in the hypotensive action of enalapril maleate related to the inhibition of angiotensin II formation.