Drugs affecting blood glucose levels

Diane S. Aschenbrenner

Research output: Chapter in Book/Report/Conference proceedingChapter


• Diabetes is primarily a disorder of carbohydrate metabolism, although it is associated with derangements of protein and fat metabolism and a series of vascular disorders. • The patient with type 1 diabetes has an absolute insulin defi ciency, cannot maintain a normal blood glucose level, and depends on exogenous insulin for survival. Combinations of short- or rapid-acting and longer-acting insulins may be administered to fully manage and control glucose levels. Basal and preprandial doses may be required to control glucose levels. During times of physiologic stress, when glucose levels are elevated (such as after surgery), the patient with diabetes may require additional monitoring and control. Critically ill patients may need to receive an insulin drip to maintain glucose levels as close to normal as possible. • The patient with type 2 diabetes has a developed insulin resistance. Although insulin is produced, it is not effective in moving glucose into the cells. Oral antidiabetic agents are used to improve glucose control. Occasionally, this patient may also need insulin to achieve glucose balance during times of stress, such as illness, or to achieve maximum control of blood glucose levels. • All insulins manage hyperglycemia by promoting cellular glucose uptake and metabolism. Insulins vary in peak, onset, and duration of action; they are similar in absorption, distribution, metabolism, and excretion. • Hypoglycemia is the most common adverse effect of insulin therapy. Severe hypoglycemia may produce loss of consciousness and is termed insulin shock. • Regular insulin has a quick onset and peak, and a short duration of therapy. Because of these pharmacokinetic features, it can be used multiple times a day, usually before meals and at bedtime. Regular insulin can be used in addition to long-acting insulin. The dose of regular insulin is often variable and based on the current blood glucose reading. This approach is known as correctional or supplemental dosing (previously referred to as slidingscale insulin). • Rapid-acting insulins, lispro, aspart, and glulisine, have a more rapid onset of action than regular insulin. When administered subcutaneously, they are administered closer to the time of a meal than regular insulin. These insulins can also be administered by an insulin pump. When used as prandial doses, they may be administered immediately after a meal if the dose varies, depending on the amount and type of food eaten. • Intermediate-acting insulins, such as NPH and detemir, have a slower onset with a peak effect occurring later than with regular insulin. Their effects also last longer than those of regular insulin. These longer-acting insulins are normally assigned a standard daily dosage that the patient takes once or twice a day. Intermediate- acting insulins may be used in combination with regular insulin or rapidacting insulins to meet both the current and long-term glucose levels of the patient. NPH can be mixed in a syringe with other insulins, but detemir cannot be mixed with any other insulin. Intermediate- or long-acting insulins are not administered by the IV route or by SC insulin pumps, or used as correctional-dose insulin. NPH is a suspension, and it is the only insulin that appears cloudy. • Long-acting glargine does not create the peak and trough in blood insulin levels that NPH does. It has a fl atter, sustained effect, which lasts for 24 hours. It is taken subcutaneously once daily at bedtime. • Combinations of NPH and regular insulins or rapid-acting insulins as well as rapid-acting insulins and protamine are available. The trade names of these products are very similar and may cause medication errors. Avoiding referring to these drugs by their trade names minimizes the risk of serious medication errors. • Insulins are very potent (a small dose creates a big effect). When drawing up insulin, the dose should always be double- checked by another nurse to prevent accidental overdosage, which could cause serious, even life-threatening, consequences to the patient. • Nursing care of the patient receiving insulin therapy calls for balancing diet, exercise, and insulin requirements; preventing and monitoring for complications of therapy; and teaching the patient how to do the same. • Glyburide is the prototype oral antidiabetic sulfonylureas. It is used to treat type 2 diabetes. It works by stimulating insulin release from the beta cells of the pancreas and by reducing glucose output from the liver. It also increases the sensitivity of the peripheral cells to insulin. The patient must make some endogenous insulin for glyburide to work. The most common adverse effect is hypoglycemia. • Other antidiabetic drugs work in different ways than the sulfonylureas. Metformin is the prototype for these drugs. Metformin decreases intestinal absorption of glucose and improves insulin sensitivity in type 2 diabetes. It rarely causes hypoglycemia when used alone. • Alpha-glucosidase inhibitors (acarbose and miglitol) inhibit enzymes needed to digest carbohydrates; thus, they produce a slower postprandial rise in glucose in type 2 diabetes. Because of how they work, if hypoglycemia does occur during their use, do not use dietary sugars (orange juice, cane sugar) but use glucose tablets. • The thiazolidinedione oral antihyperglycemic drugs rosiglitazone and pioglitazone are similar to those of the biguanides; they are antihyperglycemics and "insulin sensitizers" and are used in type 2 diabetes.Both drugs carry a Black Box warning that they may induce or exacerbate heart failure. Rosiglitazone now carries a Black Box warning that it may increase the risk of myocardial infarction. Its use is now restricted to those who cannot be controlled on other antidiabetic therapy. • Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) enzyme inhibitor; it works by enhancing the action of endogenous incretin hormones. Incretin hormones are released in response to glucose elevations that occur after a meal in order to maintain normal levels of glucose. These incretin hormones increase insulin synthesis and its release from pancreatic beta cells by intracellular signaling pathways as well as lowering glucagon secretion from the pancreas. Sitagliptin may be used as monotherapy or in combination with other oral antidiabetic drugs to treat type 2 diabetes. • Exenatide is an incretin mimetic drug and is used as an adjunct in treating patients with type 2 diabetes. Administered subcutaneously, it increases insulin synthesis, lowers glucagon secretion, slows gastric emptying, and promotes weight loss. Exenatide is not an insulin, and care must be used not to confuse it with insulin. • Pramlintide is an analogue of endogenous amylin, a hormone secreted like insulin from pancreatic beta cells. It is used as a subcutaneous supplement to insulin therapy in patients with type 1 or type 2 diabetes who have not been able to achieve suffi cient glucose control on insulin alone. It is not an insulin and cannot be mixed with an insulin. Like endogenous amylin, pramlintide delays gastric emptying, prevents postprandial rise in plasma glucagon, and promotes feelings of satiety so that the patient eats less. Adverse effects that can occur include hypoglycemia and GI distress. • Glucagon is a protein made by the pancreas that is used for emergency treatment of severe hypoglycemia. It regulates the rate of glucose production through glycogenolysis, gluconeogenesis, and lipolysis. • The management of type 1 and type 2 diabetes has become more complicated in recent years because of the variety of new drugs available to control elevated glucose levels, but these new therapies mean that patients who have previously been unsuccessful in controlling their glucose levels may be able to achieve glucose control. Long-term glucose control is important, as it prevents the serious sequelae that accompany uncontrolled diabetes.

Original languageEnglish (US)
Title of host publicationDrug Therapy in Nursing
PublisherWolters Kluwer Health Adis (ESP)
Number of pages36
ISBN (Electronic)9781469819174
ISBN (Print)9781451187663
StatePublished - Nov 7 2012
Externally publishedYes

ASJC Scopus subject areas

  • Nursing(all)


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