Carvedilol: New Considerations for Its Use in the Diabetic Patient With Hypertension

Beta blocker use improves outcomes for the diabetic patient with a history of acute myocardial infarction or coronary artery disease even more so than for the nondiabetic patient similarly afflicted. Beta blockers shift myocardial metabolism away from dependence on free fatty acids and toward greater utilization of glucose; in the process, cardiac workload drops and myocardial ischemia becomes less likely. Beta blockers also reverse the fetal gene induction program, which undoes myocardial remodeling and improves ventricular function; however, β blocker side effects in the diabetic patient can often prove their undoing. Beta blockers can deteriorate glycemic control by increasing insulin resistance. Beta blockers can also increase triglyceride levels and lower levels of high‐density lipoprotein cholesterol. In addition, vasoconstriction, caused by unopposed α activity, can worsen the symptom profile of patients with peripheral vascular disease; however, carvedilol, a combination α‐blocker/nonselective β blocker with vasodilating and insulin‐sensitizing properties, largely avoids these problems. The recently reported Glycemic Effects in Diabetes Mellitus: Carvedilol‐Metoprolol Comparison in Hypertensives (GEMINI) trial, which compared the effects of carvedilol and metoprolol tartrate on glycemic control and microalbuminuria, showed a better maintenance of glycemic control and improvement in metabolic syndrome parameters with carvedilol compared with metoprolol.