The current study was designed to evaluate (a) the efficacy of long-term use of nitrendipine in blood pressure control of patients with mild to moderate hypertension (diastolic, 90 to 120 mm Hg), aged 38 to 65 years; and (b) the relative effects of the drug on blood lipids (total cholesterol, triglycerides, and high-density lipoprptein cholesterol) and glucose metabolism (fasting glucose, 2 h postprandial glucose, and glycosylated hemoglobin). Laboratory determinations were performed 30 days before, and on the 30th, 180th, and 360th days of treatment. Nitrendipine monotherapy (mean dose 39 ± 1.44 mg/day) resulted in a significant decrease of blood pressure after 4 weeks of treatment, which was maintained throughout the 12 months of the trial without observing any tolerance to the drug. No significant change in heart rate and body weight was observed after one year of treatment. Palpitations, headache, and flushing, side effects observed occasionally during the first few weeks of treatment, disappeared during chronic use of the drug. Only one patient still complains of flushing. Although no change in fasting glucose, 2 h postprandial glucose, and glycosylated hemoglobin occurred during nitrendipine therapy, a significant decrease in high-density lipoprotein cholesterol occurred after 12 months of therapy (change – 14 mg/dl, p < 0.05). An increase in total serum cholesterol and triglycerides was observed but was not significant: 220 ± 43 and 240 ± 45 mg/dl for cholesterol, at baseline and 12 months, respectively; 119 ± 81 and 159 ± 143 mg/dl for triglycerides, at baseline and 12 months, respectively. The response to a preliminary simple dose of 20 mg of nitrendipine demonstrated that, concomitant to blood pressure reduction, nitrendipine caused a notable and acute increase in urinary volume and sodium excretion while it kept potassium excretion unchanged. The mechanisms by which nitrendipine decreases levels of high-density lipoprotein cholesterol are unknown. Further studies of these lipid changes are necessary to evaluate the clinical significance of the present results. It is suggested that the natriuretic effects of nitrendipine could explain the sustained absence of tolerance to the drug.
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