PTCE: The Basics of Medications - Endocrine Agents

Review endocrine USAN stems by looking at the table below. These stems identify the most commonly prescribed medications used to treat diabetes mellitus.
Tip: Insulin is stored in the pharmacy refrigerator prior to being dispensed.

Table: USAN Stems for Endocrine Agents

Diabetes mellitus is a chronic condition resulting from abnormally high levels of glucose. This may be due to an inadequate production of insulin by the pancreas or an inability for the cells to react to the activity of insulin. Diabetes mellitus can be further subdivided into two categories based on these mechanisms. Type I diabetes is an autoimmune disease that occurs when there is little to no production of insulin. Treatment for this type of diabetes is based solely on the use of exogenous insulin. In type II diabetes, insulin is present, but the cells are not sensitive to its action. This type of diabetes is treated with oral medications with insulin therapy and other injectables reserved for chronic resistance. Acute complications include hyperglycemia (high blood glucose levels) and hypoglycemia (low blood glucose levels). Patients should perform daily glucose testing. Their practitioner should also screen for HbA1c (a test to check for the presence of glycated hemoglobin) to assess average blood sugar over a period of 3 months.
Sulfonylureas, like glimepiride (Amaryl), are used to stimulate insulin secretion from beta cells. This class of medications is noted to cause hypoglycemia and weight gain. α-glucosidase inhibitors, including acarbose (Precose), prevent the digestion of carbohydrates that are turned into simple sugars. Serious side effects include severe stomach pain, constipation, and easy bruising. Rapid insulin secretors, such as repaglinide (Prandin), increase the sensitivity of beta cells to elevated blood glucose levels. This class of medications is taken immediately before a meal to reduce postprandial hyperglycemia. Insulin-sensitizing agents, such as the thiazolidinediones and biguanides, are also used in the treatment of type II diabetes. These include medications such as pioglitazone (Actos) and metformin (Glucophage), respectively. Dipeptidyl peptidase-IV (DPP-IV) inhibitors, such as saxagliptin (Onglyza), are used in addition to diet and exercise and have been shown to improve glucose tolerance and HbA1c. Canagliflozin (Invokana) belongs to a new class of selective sodium-glucose transporter-2 (SGLT2) inhibitors indicated as adjunct therapy to diet and exercise.
Hypothyroidism is an endocrine disorder resulting from a deficiency in the production of a thyroid hormone from the thyroid gland. Thyroid levels can be examined by checking T4 (thyroxine tetraiodothyronine) and T3 (triiodothyronine). T4 is actively converted to T3, which accounts for most of the metabolic activity. A deficiency in one or more of these hormones may warrant the initiation of medication. Medications used to treat hypothyroidism target either T4 (e.g., levothyroxine) or T3 (e.g., liothyronine sodium) production. Generally, medications targeting T4 are used because of their longer half-life, leading to once-a-day dosing and the conversion to T3 in the bloodstream. These medications are taken in the morning, 30 minutes before eating. Antacids and medications that contain iron should be avoided because they may interfere with absorption.
Hyperthyroidism is a result of an excess of thyroid hormones due to an overactive thyroid gland. TRH (thyrotropin-releasing hormone) is released from the hypothalamus, which in turn sends a signal to the pituitary gland to release TSH (thyroid-stimulating hormone). This, in turn, signals the thyroid gland to release thyroid hormones T4 and T3. Overactivity of these glands may result in an increase in and potential excessive production of thyroid hormones. The antithyroid medications methimazole (Tapazole) and propylthiouracil (PTU) are used to block the production of thyroid hormones. Patients are monitored for potential agranulocytosis, a condition that occurs due to the suppression of white blood cell production.

Table: Endocrine Agents



Insulin may also be used in the treatment of diabetes. Patients with type I diabetes mellitus are unable to produce insulin due to the autoimmune destruction of beta cells in the pancreas. A lack of insulin production leads to a dangerous increase in glucose levels. Exogenous insulin is used to provide glycemic control, reducing microvascular complications and cardiovascular events and also decreasing mortality.

A diagnosis of type II diabetes may also warrant the use of insulin to supplement oral antidiabetic therapy. Insulin regimens may include a basal (long-acting) insulin given with preprandial (premeal) short-acting or rapid-acting insulin.

Table: Insulin

Tip: Some medications used to treat gastroesophageal reflux are available without a prescription.The pharmacy technician should inform the patient of any OTC medications as noted on his or her prescription. OTC medications may be covered by insurance; coverage should be verified before filling the prescription.