Doxazosin effects on insulin and glucose in hypertensive patients. The Finnish Multicenter Study Group. This study investigates the effects of prolonged doxazosin treatment on serum lipids, glucose, serum insulin, and blood pressure in hypertensive patients. Following 26 weeks of treatment with doxazosin, supine and standing blood pressures were significantly decreased at a final mean daily dose of 6.4 mg. Blood glucose levels were significantly lower at 26 weeks than after the initial placebo period (p less than 0.05) or after 4 weeks' treatment with doxazosin (p less than 0.001). There was a significant (p less than 0.05) decrease in serum insulin levels following 4 weeks of treatment, and a highly significant (p less than 0.001) decrease after 26 weeks. In addition, doxazosin produced a significant reduction in total cholesterol (p less than 0.05) and low-density lipoprotein (LDL) cholesterol (p less than 0.01) after 26 weeks, although the levels of high-density lipoprotein (HDL) cholesterol, very-low-density lipoprotein (VLDL) cholesterol, and triglycerides showed no significant change. There was a tendency for the ratio of HDL: total cholesterol to increase. The combined changes in blood pressure, blood glucose levels, serum insulin, and serum lipids favorably affect the probability of developing coronary heart disease (CHD). 