Sulfonylureas

Sulfonylureas are another group of agent used to control blood glucose level. These drugs are only effective in patients who have functioning beta cells. They are not effective for all diabetics and may lose their effectiveness over time with others.

Sulfonylureas are further classified as first-generation or second-generation sulfonylureas.

Use of first-generation sulfonylureas is declining as more effective drugs have become available. Also, they are now thought to possibly cause an increase in cardiovascular death.

Use of second-generation sulfonylureas have several advantages over first-generation, including: safer for patients with renal dysfunction as they are excreted in urine and bile, absence of interaction to many protein-bound drugs, and longer duration of action.

All of sulfonylureas can cause hypoglycemia.

Sulfonylureas: Generic and Brand Names

Here is a table of commonly encountered sulfonylureas, their generic names, and brand names:

• First-generation sulfonylureas:
  • chlorpropamide (Diabinese)
  • tolazamide (Tolinase)
  • tolbutamide (Orinase)
• Second-generation sulfonylureas:
  • glimepiride (Amaryl)
  • glipizide (Glucotrol)
  • glyburide (Diabeta, Micronase)

Therapeutic Action

The desired and beneficial action of sulfonylureas:

• Sulfonylureas stimulate insulin release from the beta cells in pancreas. They improve insulin binding to insulin receptors and may actually increase the number of insulin receptors.
• They are also known to increase the effect of antidiuretic hormone on renal cells.

Indications

Sulfonylureas are indicated for the following medical conditions:

• Sulfonylureas are used as adjunct to diet and exercise for the treatment of type 2 diabetes older than 10 years of age; extended release form for patients older than 17 years of age; adjunct treatment with polycystic ovary syndrome.

Pharmacokinetics

Here are the characteristic interactions of sulfonylureas and the body in terms of absorption, distribution, metabolism, and excretion:

Route	Onset	Peak	Duration
Oral	Slow	2-2.5 h	10-16 h

Half-life (T1/2)	Metabolism	Excretion
6.2-17 h	Liver	Urine

Contraindications and Cautions

The following are contraindications and cautions for the use of sulfonylureas:

• Allergy to sulfonylureas. Avoid hypersensitivity reactions
• Type 1 diabetes. These patients do not have functioning beta cells and would have no benefit from the drug.
• Pregnancy and lactation. Potential adverse effect on the fetus or neonate.

Adverse Effects

Use of sulfonylureas may result to these adverse effects:

• Hypoglycemia (most common)
• GI distress (nausea, vomiting, epigastric discomfort)
• Allergic skin reactions

Interactions

The following are drug-drug interactions involved in the use of sulfonylureas:

• Decreased excretion with drugs that acidify urine

Nursing Considerations

Here are important nursing considerations when administering agents to control blood glucose level:

Nursing Assessment

These are the important things the nurse should include in conducting assessment, history taking, and examination:

• Assess for contraindications or cautions (e.g. history of allergy to the drugs, pregnancy and lactation status, severe renal or hepatic dysfunction, etc.) which are contraindications in the use of these agents.
• Perform a complete physical assessment to establish baseline status before beginning therapy and to evaluate effectiveness and any potential adverse effects during therapy.
• Assess orientation and reflexes; baseline pulse and blood pressure; adventitious breath sounds; abdominal sounds and function, to monitor effects of altered glucose levels.
• Assess body systems for changes suggesting possible complications associated with poor blood glucose control.
• Investigate nutritional intake, noting any problems with intake and adherence to prescribed diet, to help prevent adverse reactions to drug therapy.
• Assess activity level, including amount and degree of exercise, which can alter serum glucose levels and dosage needs for these drugs.
• Monitor blood glucose levels as ordered to evaluate effectiveness of drug and glycemic control.
• Monitor results of laboratory tests, including urinalysis, for evidence of glycosuria, and renal and liver function tests, to determine the need for possible dose adjustment and evaluate for signs of toxicity.

Nursing Diagnoses and Care Planning

Here are some of the nursing diagnoses that can be formulated in the use of this drug for therapy:

• Risk for unstable blood glucose related to ineffective dosing of antidiabetic agents
• Imbalanced nutrition: less than body requirements related to metabolic effects
• Disturbed sensory perception: kinesthetic, visual, auditory, and tactile related to glucose levels

Implementation with Rationale

These are vital nursing interventions done in patients who are taking sulfonylureas:

• Administer the drug as prescribed in the appropriate relationship to meals to ensure therapeutic effectiveness.
• Ensure that patient has dietary and exercise regimen and using good hygiene practices to improve the effectiveness of the insulin and decrease adverse effects of the disease.
• Monitor nutritional status to provide nutritional consultation as needed.
• Monitor response carefully; blood glucose monitoring is the most effective way to evaluate dose. Obtain blood glucose levels as ordered to monitor drug effectiveness.
• Monitor patients during times of trauma, pregnancy, or severe stress, and arrange to switch to insulin coverage as needed.
• Provide comfort measures to help patient cope with drug effects.
• Provide patient education about drug effects and warning signs to report to enhance patient knowledge and to promote compliance.

Evaluation

Here are aspects of care that should be evaluated to determine effectiveness of drug therapy:

• Monitor patient response to therapy (stabilization of blood glucose levels).
• Monitor for adverse effects (hypoglycemia and gastrointestinal distress).
• Evaluate patient understanding on drug therapy by asking patient to name the drug, its indication, and adverse effects to watch for.
• Monitor patient compliance to drug therapy.

Recommended Resources

Our recommended nursing pharmacology resources and books:

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See Also

Here are other nursing pharmacology study guides:

• Nursing Pharmacology – Study Guide for Nurses
  Our collection of topics related to nursing pharmacology
• Pharmacology Nursing Mnemonics & Tips
  These nursing mnemonics aim to simplify the concepts of pharmacology through the use of a simple, concise guide.
• Generic Drug Name Stems Cheat Sheet
  Learn about these generic drug name stems to help you make sense of drugs easier!
• Common Drugs and Their Antidotes
  A guide to drug antidotes that nurses should be familiar about.
• IV Fluids and Solutions Guide & Cheat Sheet
  Get to know the different types of intravenous solutions or IV fluids in this guide and cheat sheet.
• Drug Dosage Calculations NCLEX Practice Questions (100+ Items)
  Care to take the challenge? This quiz aims to help students and registered nurses alike grasp and master the concepts of medication calculation.

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References and Sources

References and sources for this pharmacology guide for Sulfonylureas:

• Karch, A. M., & Karch. (2011). Focus on nursing pharmacology. Wolters Kluwer Health/Lippincott Williams & Wilkins. [Link]
• Katzung, B. G. (2017). Basic and clinical pharmacology. McGraw-Hill Education.
• Lehne, R. A., Moore, L. A., Crosby, L. J., & Hamilton, D. B. (2004). Pharmacology for nursing care.
• Smeltzer, S. C., & Bare, B. G. (1992). Brunner & Suddarth’s textbook of medical-surgical nursing. Philadelphia: JB Lippincott.