Effects of antihypertensive drugs on glucose metabolism and cardiovascular events

Diuretics and beta-blockers (conventional antihypertensive therapy) may increase the level of blood glucose. Such an increase could enhance the risk of cardiovascular events and have an unfavourable effect on prognosis, but available documentation is not conclusive. The material consists of literature collected over many years, supplemented with literature retrieved through an extensive search (non-systematic) in Pubmed. Several studies, of 4-6 years duration, have shown that conventional therapy induces a small increase of blood glucose without increasing cardiovascular events. Newer antihypertensive drugs (angiotensin converting enzyme (ACE) inhibitors, angiotensin II (AII)- receptor blockers and calcium blockers) do not have this effect. Conventional therapy can also prevent cardiovascular events in patients with diabetes. Several studies on hypertension have shown that drugs' ability to reduce blood pressure is most decisive for their prevention of events. In most cases, diuretics and beta-blockers are as effective as the newer antihypertensives, but drugs with an effect on the renin-angiotensin system are usually preferred as first choice in patients with diabetes. However, when several drugs must be combined in order to achieve the blood pressure goal in diabetic patients (< 130/80 mm Hg), diuretics and beta-blockers may be administered.