Hyperinsulinemia, insulin resistance, and the treatment of hypertension.

Treatment with beta-blockers and diuretics has been associated with an increased risk of developing diabetes mellitus in three prospective cohort studies. Prospective, randomized studies with antihypertensive drugs have demonstrated differences between different classes of drugs regarding effects on insulin sensitivity. Thus, treatment with beta-blockers or diuretics is associated with impairment in insulin sensitivity, whereas most modern calcium channel blockers and angiotensin converting enzyme (ACE) inhibitors are neutral. However, there are exceptions within the different classes. Captopril seems to differ from the other ACE inhibitors and results in improvement of insulin sensitivity. The most pronounced improvements have been obtained with alpha 1-blockers. In populations at high risk for diabetes mellitus, it may be justified to select drugs that improve insulin sensitivity when treating hypertension in insulin resistant individuals.