Patient Care Endocrinology & Cardiology - December 2007 - (Page 7)

Options for managing diabetes Three types of basal insulin therapy Ideally, basal insulin therapy should provide adequate and reproducible steady-state plasma insulin levels without causing hypoglycemia. Our expert reviews the current basal insulin options when patients fail oral antidiabetic drugs. AUTHOR NASSER MIKHAIL, MD, MSc, Associate Clinical Professor of Medicine UCLA School of Medicine; and Chief, Endocrinology Division, OliveView-UCLA Medical Center, Sylmar, Calif. U Article at a glance I I I NPH (neutral protamine Hagedorn) insulin given once or twice daily is the traditional form of basal insulin, which is increasingly replaced by newer types of basal insulin. Insulin glargine (Lantus) has a duration of action lasting 20 to 24 hours without a pronounced peak effect. Compared with NPH insulin, insulin glargine has similar effect on hemoglobin A1c (HbA1c ) values, but is associated with less nocturnal hypoglycemia. The duration of action of insulin detemir (Levemir) ranges from 12 to 20 hours. It is similar to NPH insulin in decreasing HbA1c levels. However, the use of insulin detemir is generally associated with less hypoglycemia (mainly nocturnal), less weight gain, and less variation of blood glucose. nder physiologic conditions, insulin secretion is formed of 2 components—a chronic low basal release in the fasting state that suppresses lipolysis and hepatic glucose production, and much higher insulin surges to control hyperglycemia following meals.1 In patients with insulin deficiency, the goal of basal and bolus insulin therapy is to mimic the physiologic patterns of the basal and postprandial insulin release, respectively. Basal insulin therapy, like pancreatic basal insulin secretion, should provide adequate and reproducible steady-state plasma insulin levels without a peak action and without causing hypoglycemia. This article discusses the currently available basal insulin regimens: neutral protamine Hagedorn (NPH) insulin (Humulin N, Novolin N), insulin glargine (Lantus), and insulin detemir (Levemir). This article does not discuss lente and ultralente insulins, the production of which has been discontinued.2 NPH INSULIN NPH insulin was named after Hans Christian Hagedorn who first reported in 1936 that the absorption of human regular insulin was delayed and its action prolonged after the addition of protamine.3 In 1946, Krayenbuhl and Rosenberg observed that protamine and insulin mixed in the presence of zinc in equivalent amounts at physiologic pH (a condition that they described as “isophane”) produced crystals of protamine insulin.4 Hence, the resultant insulin was called neutral protamine Hagedorn or isophane insulin. The onset of action of NPH insulin is therefore delayed because of the addition of protamine and starts within 2 to 4 hours compared with about 30 to 60 minutes with human regular insulin.5 NPH insulin has become the most widely used basal insulin. However, it has several limitations: • First, its duration of action ranges only from 12 to 16 hours. 5 • Second, it exhibits a peak effect 4 to 10 hours after injection that may virtually precipitate hypoglycemia. Therefore, nocturnal hypoglycemia can occur if NPH insulin is injected at dinnertime. Switching the injection of NPH insulin from dinnertime to bedtime may decrease DECEMBER 2007 PATIENT CARE ENDOCRINOLOGY & CARDIOLOGY 7

Table of Contents Feed for the Digital Edition of Patient Care Endocrinology & Cardiology - December 2007

Patient Care Endocrinology & Cardiology - December 2007 Research Digest Contents Medicine in the News Options for Managing Diabetes: Three Types of Basal Insulin Therapy Using the New AHA Guidelines for Preventing Coronary Heart Disease in Women Cardiovascular and Metabolic Implications of Polycystic Ovary Syndrome Case & Comment Classified Advertising Clinical Clips

Patient Care Endocrinology & Cardiology - December 2007

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.