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Biomedical subjects

L Terzoli

Publications and source records attributed to L Terzoli.

42 records · Page 3Linked to original sources
PubMed1975

Hypotensive and renin-suppressing activities of propranolol in hypertensive patients.

1. In patients with mild or moderate essential hypertension, oral propranolol, given in incremental doses, produced a moderate but significant lowering of blood pressure which was correlated with the concentration of propranolol in plasma. 2. Propranolol also reduced plasma renin activity (PRA) in the supine posture, on standing and after intravenous frusemide. However, 'supine' and 'frusemide' PRA values were markedly reduced at a plasma concentration of propranolol that had little effect on blood pressure. 3. On administration of propranolol there was little correlation between blood pressure decrease and PRA suppression, and even less between pretreatment PRA values and hypotensive response. 4. It is concluded that in patients with mild and moderate hypertension and low or normal plasma renin activity, suppression of PRA is not an important determinant of the hypotensive response to propranolol.

Administration, Oral↗
PubMedDate not supplied

Effects of single and repeated doses of the calcium antagonist felodipine on blood pressure, renal function, electrolytes and water balance, and renin-angiotensin-aldosterone system in hypertensive patients.

Doses of 10 mg b.i.d. of the new dihydropyridine calcium antagonist, felodipine, were tested for seven consecutive days in 11 hospitalized hypertensive patients. A significant reduction of both systolic and diastolic blood pressures, with patients in both the supine and upright positions, occurred immediately after the first dose and was maintained (daily average 15%) throughout the following days. An increase in heart rate was observed after the first dose (15 and 23 beats/min, in supine and upright postures), and subsequently declined to average values of 8 and 14 beats/min on the seventh day. There was a marked natriuretic response during the first and second day, during which an average negative sodium balance of 95 mmol developed; on the following days sodium output was not significantly different from control, but a negative balance averaging 135 mmol was still present on the seventh day of felodipine administration. A moderate negative potassium balance also progressively developed and reached -48 mmol on the seventh day. Glomerular filtration rate was unchanged, but renal plasma flow increased significantly during administration of felodipine. Plasma renin activity and plasma aldosterone were also increased very moderately by felodipine. Compared with previous observations by our group with higher doses of felodipine (12.5, 25, and 50 mg t.i.d.), 10 mg b.i.d. of this new calcium antagonist appear to exert a marked and prolonged blood pressure reduction, accompanied by a definite natriuretic instead of an antinatriuretic effect.

Adult↗
PubMedDate not supplied

Effects of prazosin on autonomic control of circulation in essential hypertension.

Prazosin, an antihypertensive agent that reduces blood pressure (BP) mainly through a blockade of alpha-adrenergic receptors, may, in theory, affect sympathetic control of circulation to an extent that impairs circulatory hemeostasis. This possibility was studied in subjects with essential hypertension by examining the cardiovascular effects of several stimuli that induce a powerful and diversified activation of the sympathetic noradrenergic activity (dynamic and isometric exercise, cold exposure) and of stimuli that exert a powerful inhibitory influence upon the sympathetic nervous system (carotid baroreceptor reflex). Before and after 15 days of continuous administration of prazosin (2-5 mg), 3 times a day, measurements were made of BP (intraarterial catheter), heart rate, cardiac output (thermodilution), and peripheral resistance. Prazosin reduced mean arterial pressure (10%) and peripheral resistance (9%) at rest, and it did not affect heart rate and cardiac output. Neurally mediated changes in arterial pressure, cardiac output, and peripheral resistance during dynamic or isometric exercise and cold exposure were unaffected by the drug; also unaffected were the cardiovascular responses to increase and decrease in carotid baroreceptor activity obtained by varying carotid transmural pressure through a variable neck pressure chamber device. Thus, the hypotensive and vasodilating effect of prazosin in essential hypertension is not accompanied by an impaired response to neural excitation influences upon the cardiovascular system. Also, the inhibitory influences originating from the carotid baroreflex are unchanged. These data indicate that circulatory homeostasis is largely preserved during administration of prazosin at clinically effective doses.

Adult↗
PubMedDate not supplied

Felodipine, a new vasodilating drug: blood pressure, cardiac, renal, and humoral effects in hypertensive patients.

We studied the antihypertensive action of felodipine, a new dihydropyridine vasodilator interfering with intracellular calcium mechanisms, in 11 patients with essential hypertension whose supine blood pressure averaged 181/109 mm Hg after 5 days of placebo administration. Felodipine, 12.5 mg t.i.d., for 3 days, caused a marked reduction (-39/-19 mm Hg) of supine systolic and diastolic pressures. Doses of 25 and 50 mg t.i.d., for three consecutive days, caused only a slight further reduction of blood pressure. At the highest dose tested all patients had their supine blood pressure brought down to values below 150 mm Hg systolic and 90 mm Hg diastolic at all six daily measurements. The antihypertensive effect was of the same magnitude when the patients lay supine or stood upright. Lowering of blood pressure was accompanied by tachycardia, which was quite moderate after the 12.5 mg t.i.d. dose, but more conspicuous with the two higher doses. There was some increase in plasma renin activity and in plasma aldosterone. A significant decrease in renal sodium and water excretion occurred only during administration of the highest dose of 50 mg t.i.d., when reduction in blood pressure was pronounced and there were reflex increases in plasma renin activity and plasma aldosterone.

Aldosterone↗