Diabetes Mellitus
Manual of Clinical Nutrition Management III- 29 Copyright © 2013 Compass Group, Inc.
DIABETES MELLITUS: ORAL GLUCOSE-LOWERING
MEDICATIONS AND INSULIN
Table III- 7 : Glucose-Lowering Agents (1-3)
Generic Name Trade
Name(s)a
Classification Onset (h) Duration (h)Chlorpropamideb Diabinese Sulfonylurea 1 24 - 72
Glyburideb DiaBeta,
Micronase,
Glynase
Sulfonylurea
1.5
1.5
1.512 - 24
12 - 24
24
Glipizideb Glucotrol,
Glucotrol XL
Sulfonylurea 1
112 - 16
24
Glimepirideb Amaryl Sulfonylurea 2 - 3 12 - 24
Nateglinideb Starlix Nonsulfonylurea 0.33 1 - 4
Repaglinideb Prandin Nonsulfonylurea 0.25-0.5 1
Metformin Glucophage Biguanide 1 - 3 6 - 12
Glucophage XR Biguanide 0.5- 3 12 - 24
Glyburide-Metformin
(combination drug)
Glucovance Sulfonylurea-Biguanide
Half-life, 6.2 24 - 48Pioglitazone Actos Thiazolidinedione 0.5, peak 2- 4 24
Rosiglitazone Avandia Thiazolidinedione 1 12 - 24
Acarbose Precose -glucosidase inhibitor Immediate 6
Miglitol Glyset (^) -glucosidase inhibitor Immediate 6
Sitagliptin Januvia Dipeptidyl peptidase IV
inhibitor
1 24
Exenatide Byetta Incretin mimetic 0.5- 1 6
Pramlintide Symlin Amylinomimetic 0.5 6
aAll product names are registered trademarks of their respective companies.
bThese oral hypoglycemic agents have the potential to cause hypoglycemia, since their mode of action increases the release of insulin
from the pancreas. Patients who take these oral agents may require snacks if there is more than 4 to 5 hours between meals. A bedtime
snack may also be necessary and should be evaluated as part of the individualized meal plan (4).
Discussion
Newer oral or injectable glucose-lowering medications, alone or in combination, provide numerous treatment
options for achieving glycemic control (1,2). A combination of two or three medications may be used by
persons with type 2 diabetes that is not adequately controlled by nutrition therapy (1,2). If glycemic control is
not attained, insulin, either alone or in combination with oral medication, may be necessary. The transition to
insulin often begins with long-acting insulin given at bedtime to control fasting glucose levels and glucose-
lowering medication given during the day to control daytime and postprandial glucose levels (1,2). Many
patients with type 2 diabetes require two or more insulin injections daily to achieve glycemic control (1).
Some of these patients will attain better glycemic control with three or four daily insulin injections or with an
insulin pump (1-3). An algorithm for the treatment of type 2 diabetes has been established by the American
Diabetes Association and European Association for the Study of Diabetes (4). This algorithm recommends the
initiation of metformin therapy at diagnosis, along with lifestyle intervention that includes medical nutrition
therapy (1,4,5). The algorithm calls for the addition of another oral agent or insulin if the percentage of
hemoglobin A1c goal exceeds 7% (1,5).
Glucose-Lowering Medications
Commonly used glucose-lowering medications and their onset and duration are listed in Table III-7. Each
class of drug has a different mechanism of action, as described below (1-3).
Insulin secretagogues (sulfonylureas and nonsulfonylureas): These drugs promote insulin secretion by
the beta cells of the pancreas. Sulfonylureas are metabolized by the liver and cleared by the kidney (except
glimepiride); therefore, caution is needed for patients who have impaired renal function (2). Patients should
be informed that missed meals or snacks could cause hypoglycemia (2). In addition, these medications are
associated with an increase in appetite and possible weight gain (2). Compared with sulfonylureas,
nonsulfonylureas cause less weight gain and have an earlier onset, shorter duration (1 to 6 hours), and a