Oral antidiabetic medications - Biguanides and thiazolidinediones: Nursing pharmacology

Biguanides and thiazolidine diions are medications primarily used to treat type 2 diabetes mellitus. Type 2 diabetes is characterized by insulin resistance, which is when tissue cells have trouble responding to insulin in order to use glucose from the blood.

As a result, tissue cells starve for energy despite having high blood glucose levels, which is called hyperglycemia. Now, the most commonly used by guanite is metformin, whereas commonly used thiazolidine diions are medications that end with the suffix glitazone, like pioglitazone and rosaglitazone.

These medications can be taken orally. Once administered, they decrease insulin resistance by increasing insulin sensitivity, and thus the uptake of glucose by muscle and fat cells.

In addition, these medications inhibit gluconeogenesis, or glucose production in the liver. The combination of these two mechanisms ultimately leads to a decrease in blood glucose.

All right, now the good news about biguanides and thiazolidine diions is that they never cause hypoglycemia when used alone as monotherapy.

However, both groups have several other side effects. Clients taking biguanites can often present with gastrointestinal disturbances, such as anorexia, nausea, vomiting, and diarrhea.

In addition, they might experience dizziness, fatigue, and a characteristic bitter or metallic taste. As a boxed warning, biguanites can lead to lactic acidosis, which can be a life-threatening complication.

Lastly, prolonged use of biguanites decreases absorption of vitamin B12 and folic acid, which can cause deficiency. On the other hand, thiazolidine ions can increase the risk of fractures and can also lead to bladder cancer.

Thiazolidine diions also have a box warning for heart failure, while only rosaglitazone has a box warning about an increased risk of myocardial infarction.

As far as contraindications go, both biguanides and thiazolidine ions should not be used in clients with hepatic disease, as well as in clients experiencing diabetic acidosis or DKA and should be used with caution in clients with type one diabetes mellitus as adjunct therapy to insulin.

Additional precautions include pregnancy and breastfeeding, as well as elderly clients. Finally, these medications should be used with caution in clients with thyroid, cardiopulmonary, or renal disease.

Now, biguanides in particular should also be avoided in clients with renal failure or alcoholism. Additionally, biguanites should be stopped 48 hours before and after the client undergoes radiographic contrast administration, since it increases the risk of developing acute renal failure or lactic acidosis.

On the other hand, thiazolidine ions should not be used in clients with osteoporosis, polycystic ovary syndrome, and bladder cancer or secondary malignancy.

OK, before administering an oral diabetic medication like biguanide or thiazolidine diione, be sure to review their most recent laboratory test results, including blood glucose, hemoglobin A1C, renal and hepatic function.

Explain how the medication works to improve their body's sensitivity to insulin and ultimately lower their blood glucose level.

Be sure to remind them that these medications are most effective when used along with an anti-diabetic regimen, which includes following a low-carbohydrate and high fiber diet, regular physical activity, and frequent blood glucose monitoring.

Also review with your client the symptoms of hyperglycemia, such as fatigue, blurred vision, as well as increased thirst, appetite, and urination.

Now, if your client is prescribed metformin, teach them to take immediate release tablets twice daily along with their morning and evening meals.

If they're prescribed an extended release tablet, instruct them to take it just once daily with their evening meal. Next, be sure to teach your client about side effects they may experience while taking metformin, such as gastrointestinal disturbances like diarrhea, nausea, vomiting, or a metallic taste in their mouth.

Also, remind them that metformin can cause decreased absorption of vitamin B12 and folic acid. So encourage them to consume foods that are high in these vitamins, such as leafy green vegetables, low-fat dairy products, legumes, salmon, and chicken.

Also caution your client to avoid alcohol while taking metformin. Lastly, prompt them to contact their healthcare provider immediately if they experience symptoms of lactic acidosis, such as malaise, myalgia, and hyperventilation.

If your client is prescribed a thiazolidine dione like pioglitazone, teach them to take their medication once daily with or without food.

Next, be sure to review with your client the side effects that could signal the beginning of heart failure, such as edema, weight gain, and dyspnea, as well as early signs of liver damage, such as fatigue, abdominal pain, anorexia, and dark urine.

And symptoms associated with bladder cancer, such as urinary urgency or blood in the urine. If your client develops any of these symptoms, they should notify their healthcare provider right away.

Lastly, teach your client how to reduce the risk of fractures by engaging in regular weight-bearing exercises, and including foods high in calcium and Vitamin D in their diet, such as spinach, broccoli, low-fat dairy products, as well as fortified foods like cereals, juices, soy drinks, and tofu.

Finally, evaluate for the therapeutic effect of improved glucose control. Keep a close eye on their renal and hepatic function during treatment, and monitor for the development of side effects.

Alright, as a quick recap, biguanides and thiazolidine diions are oral medications primarily used to treat type 2 diabetes mellitus.

Both of these classes of medications increase insulin sensitivity, while also inhibiting gluconeogenesis in the liver. Side effects of biguanides include gastrointestinal disturbances and can cause a metallic taste in the mouth, and can increase the risk of lactic acidosis.

Thiazolidine diions can increase the risk of heart failure, fractures, and bladder cancer. Nursing considerations are focused on monitoring blood glucose levels, renal and hepatic function, as well as side effects.

Finally, client teaching includes safe self-administration, continuation of their anti-diabetic regimen and dietary modifications, and recognition of side effects.