Effects of a low-sodium high-potassium salt in hypertensive patients treated with metoprolol: a multicentre study.

A multicentre study, involving 358 subjects, was carried out to evaluate the effects of a low-Na/high-K dietary salt in hypertensive patients receiving beta-blocker monotherapy. At the end of a 4-week treatment period with 200 mg slow-release metoprolol patients were randomly divided into two groups: one group was given common salt and the other the dietary salt. Both salts were given at table, in double-blind conditions over a period of 4 weeks. The dietary salt group showed a systolic and diastolic blood pressure (BP) reduction (4.2 and 3.0 mmHg, respectively, in the supine position and 4.0 and 2.5 mmHg in the standing position), which was virtually absent in the common salt group. A statistically significant difference between the two groups was found only between the systolic values (P less than 0.05). Twenty-four-hour urinary sodium excretion did not change in either group, while the excretion of 24-h urinary potassium increased significantly in the dietary salt group. It is concluded that in mild or moderately hypertensive patients already receiving a beta-blocker, ancillary treatment with a low-Na/high-K salt can be expected to lead to a further, slight reduction in systolic BP, probably due to the daily potassium load (around 20 mmol).

Effects of moderate salt restriction in hypertensive patients treated with oxprenolol or chlorthalidone.

Ninety-five hypertensive out-patients, whose lying diastolic blood pressure was still greater than or equal to 95 mm Hg after a 4-week treatment with oxprenolol slow release 160 mg/day or chlorthalidone 25 mg/day, restricted their daily sodium intake for a 4-week period, while continuing to receive the previous pharmacological therapy. The dietary intervention, appositely formulated to moderately restrict sodium intake, resulted in a high patient compliance as assessed by the significant (p less than 0.01) reduction in the 24-hour urinary sodium excretion. At the end of the 4-week dietary period, a significant (p less than 0.01) decrease in lying and standing systolic and diastolic blood pressure was observed in both the oxprenolol and chlorthalidone treated groups. These results suggest that a moderate reduction in sodium intake, obtained from a low sodium diet characterized by high patient compliance and easily followed in everyday life, is effective in lowering blood pressure in hypertensive patients who don't respond satisfactorily to pharmacological therapy alone.

Comparison of three different methods of monitoring unwanted effects during antihypertensive therapy.

In a double-blind, randomized, crossover, multicenter study performed in 227 hypertensive outpatients, two antihypertensive drugs, oxprenolol and chlorthalidone, were investigated to determine unwanted effects. Three main methodologic procedures were applied: the conventional evaluation of unwanted effects by the physician and involving the whole patient population, the checklist, and the free questionnaire. The latter two were assigned by randomization to the patients themselves. The study showed that unwanted effects seem to be frequently overreported when a checklist is used, whereas the free questionnaire gives more information about the symptoms of the disease than about the tolerance of the drug. The conventional method, when physicians are well-informed and sensitized to the problem, seems to provide more reliable information about unwanted effects of a drug.

Plasma lipid and lipoprotein changes in hypertensive patients treated with propranolol and prazosin.

The effects of propranolol and prazosin on plasma lipoproteins in patients with essential hypertension were evaluated according to a crossover protocol of two 8-week periods with a washout of 4 to 6 weeks. Eleven patients with moderate hypertension (greater than 90 but less than or equal to 144 mm Hg, diastolic) and slightly overweight (+10% to +/- +30%, according to Metropolitan Life Insurance tables) were selected. No dietary changes were prescribed. Plasma cholesterol, triglycerides (TG), and lipoprotein changes were monitored at the beginning of each sequence and at 2-, 4- and 8-week intervals. Prazosin, when given first, did not essentially modify any of the metabolic parameters, except for a slight elevation in plasma apoprotein AI levels, i.e., the main protein component of high density lipoprotein (HDL); propranolol caused a significant rise in total TG and very low density lipoprotein TG (VLDL-TG) levels (+37.3% and +23.9%, respectively). Somewhat lower total TG (+19.6%) and vLDL (17.8%) TG elevations were noted when propranolol was given first; plasma glucose was also significantly raised (+12.8%). Triglyceride and glucose levels returned to normal upon changing to prazosin. Total plasma- and lipoprotein-associated cholesterol levels were essentially unchanged with either drug; similarly, no significant changes were detected in total plasma apoprotein B (the main protein component of LDL and also VLDL), a component of apoprotein AI levels. Uric acid levels were slightly raised on propranolol. There was an 8.8% reduction in uric acid levels when the medication changed from propranolol to prazosin.