Drugs Affecting the Endocrine System PDF 2024

Drugs Affecting the Endocrine System OBJECTIVE 4.3 PART 1 PHARMACOLOGY PN 1290 WINTER 2024 This Photo by Unknown Author is licensed under CC BY-SA-NC Learner Objectives 4.3 Discuss the main actions and adverse effects of drugs affecting the endocrine system. 4.3.1 Discuss the purpose of commonly use...

Drugs Affecting the Endocrine System OBJECTIVE 4.3 PART 1 PHARMACOLOGY PN 1290 WINTER 2024 This Photo by Unknown Author is licensed under CC BY-SA-NC Learner Objectives 4.3 Discuss the main actions and adverse effects of drugs affecting the endocrine system. 4.3.1 Discuss the purpose of commonly used medications for the endocrine system. 4.3.2 Describe the therapeutic and adverse effects of commonly used medications for the endocrine system. 4.3.3 Discuss examples of commonly used medications for the endocrine system. 4.3.4 Discuss common drug interactions related to medications for the endocrine system. 4.3.5 Discuss nursing interventions when administering these medications across the life span. Thyroid & Antithyroid Medications CHAPTER 32 Thyroid Function The thyroid gland secretes three hormones essential for proper regulation of metabolism: Thyroxine (T4) Tri-iodothyronine (T3) Calcitonin The thyroid is located close to the parathyroid glands, which lie just behind it. These are responsible for maintaining calcium levels in the blood. TSH (thyroid stimulating hormone) is secreted by the anterior pituitary in response to low T3 & T4 Hypothyroidism: Deficiency in Thyroid Hormones Primary: Abnormality in the thyroid gland itself Secondary: Results when the pituitary gland is dysfunctional and does not secrete thyroid-stimulating hormone (TSH) Tertiary: Results when the hypothalamus gland does not secrete thyrotropinreleasing hormone, which in turn, reduces TSH and thyroid hormones Congenital hypothyroidism (Cretinism): Hyposecretion of thyroid hormone during youth which leads to a low metabolic rate, short stature, severely delayed sexual development, and possible intellectual disabilities. Myxedema: Hyposecretion of thyroid hormone during adulthood may lead to decreased metabolic rate, loss of mental and physical stamina, weight gain, loss of hair, firm edema, yellow dullness of the skin. Goiter: Enlargement of the thyroid gland. Results from overstimulation of the gland by elevated levels of TSH Levothyroxine (synthroid) Synthetic thyroid hormone T4 Thyroid Replacement Medications Liothyronine (cytomel) Synthetic thyroid hormone T3 Desiccated thyroid (thyroid) Natural thyroid hormone T3 and T4 Used to replace what the thyroid gland itself cannot produce to achieve a euthyroid condition (levothyroxine). Thyroid Replacement Drugs: Indications Increase metabolism to normal levels, excess causes symptoms of hyperthyroidism as well as other adverse effects. Used for prevention or treatment of various types of goiters. Replacement hormonal therapy for patients whose thyroid glands have been surgically removed or destroyed by radioactive iodine in the treatment of thyroid cancer or hyperthyroidism. Hypothyroidism of pregnancy Thyroid Replacement Drugs: Adverse Effects/Interactions Cardiac dysrhythmia is the most significant adverse effect. May also cause: Table 32.2 Tachycardia Palpitations HTN Insomnia Tremors Headache Anxiety Diarrhea/cramps Menstrual irregularities Weight loss Sweating Heat intolerance Fever Interactions May enhance anticoagulants, the activity of oral Taking with digoxin may decrease serum digoxin levels. Cholestyramine binds to thyroid hormone in the gastrointestinal (GI) tract, which possibly reduces the absorption of both drugs. Patients with diabetes taking a thyroid drug may require increased dosages of their hypoglycemic drugs. The use of thyroid preparations with epinephrine in patients with coronary disease may induce coronary insufficiency. Hyperthyroidism: Excess Thyroid Hormones Caused by several diseases: Graves’ disease: An autoimmune disease that leads to a generalized overactivity of the entire thyroid gland. Multinodular goiter disease. Thyroid storm (induced by stress or infection): A severe and potentially life-threatening complication of hyperthyroidism. Affects multiple body systems, resulting in overall increase in metabolism Diarrhea Flushing Increased appetite Muscle weakness Sleep disorder Altered menstrual flow Palpitations Nervousness Heat intolerance Irritability Treatment of Hyperthyroidism Radioactive iodine: works by destroying the thyroid gland, called “ablation”. Surgery to remove all or part of the thyroid gland. Lifelong thyroid hormone replacement will be needed. Antithyroid Drugs: Impede the process required to make thyroid hormones Prevent surge of thyroid hormones that occurs during radioactive iodine therapy or after surgical removal of thyroid Thioamide derivatives – Thiamozole (Tapazole), Propylthiouracil Adverse Effects: Liver and bone marrow toxicity are the most serious. Other common effects – Table 32.4 Nursing Implications Cautious use is advised for those with cardiac disease or HTN and for pregnant women. During pregnancy, treatment for hypothyroidism should continue. Fetal growth may be stunted if maternal hypothyroidism is untreated during pregnancy. Take in the morning to prevent insomnia. Report any unusual symptoms, chest pain, or heart palpitations. Teach patients that therapeutic effects may take several weeks to occur. Best taken before breakfast on an empty stomach. Teach patients the importance of alerting health care providers of thyroid medication use. Never stop abruptly. Avoid foods high in iodine for those on antithyroid treatment (tofu, iodized salt, seafood). Caution use in older adults – more sensitive to therapy, and have more adverse effects due to decreased liver/kidney functions Interactions: Enhance anticoagulants, decrease serum digoxin levels, decrease effectiveness of hypoglycemics Antidiabetic Medications CHAPTER 33 Insufficient insulin secretion from the pancreas A high level of self management is key to successful diabetes treatment Diabetes S/S include: Elevated blood sugar Polyuria Polydipsia Polyphagia Glucosuria Weight loss Fatigue Blurred vision Type 1: Lack of insulin production by the pancreas beta cells - requires exogenous insulin. Diabetes Table 33.2 Type 2: Most common type. Caused by insulin deficiency and/or insulin resistance. Several comorbid conditions: Obesity, Coronary heart disease, Dyslipidemia, HTN, Increased risk for thrombotic (blood clotting) events Gestational: Hyperglycemia that develops during pregnancy. Insulin must be given to prevent birth defects. Usually subsides after delivery Type 1: Always requires insulin therapy Diabetes Treatment Type 2: Lifestyle changes and oral drug therapy. Insulin when oral meds no longer provide glycemic control. Weight loss Improved dietary habits Smoking cessation Reduced alcohol consumption Regular physical exercise Functions as a substitute for the endogenous hormone Restores the diabetic patient’s ability to: Antidiabetic Drugs: Insulins Metabolize carbohydrates, fats, and proteins. Store glucose in the liver. Convert glycogen to fat stores. Goal: Tight glucose control,and a reduction of long term complications (Table 33.1) Four major classes for insulin Rapid acting Short acting Intermediate acting Long acting Insulins Rapid Acting Short-Acting Onset: average of 10 to 15 minutes Peak: 1 to 2 hours Duration: 3 to 5 hours Patient must eat a meal after injection or there will be a high risk of hypoglycemia. Example: Insulin lispro (Humalog®), Insulin aspart (NovoRapid®) Regular insulin (Humulin R, Novolin ge Toronto) Onset (SQ): 30 – 60 minutes Peak (SQ): 2 to 3 hours Duration (SQ): 6.5 hours Patients should eat a meal after injection with regular insulins as well. Insulins Intermediate-Acting Insulin NPH - Cloudy appearance Often combined with regular insulin to reduce number of injections needed per day Onset: 2-4 hours Peak: 4-10 hours Duration: up to 12-18 hours Others: Humulin N, Novolin Long-Acting Insulin glargine (Lantus) Clear, colourless solution Constant level of insulin in the body, usually dosed once daily. Onset: 90 minutes Peak: none Duration: ~20-24 hours Insulin detemir (Levemir) Duration of action is dose dependent. Lower doses require twice-daily dosing. Higher doses may be given once daily. Lantus and Levemir must be given alone. Fixed combinations FixedCombination Insulins Humulin 30/70 Novolin 30/70, 40/60, 50/50 NovoMix® 30 Humalog Mix25® Humalog Mix50® Each contains two different insulins in fixed combinations. One intermediate and one rapid acting. You can also mix insulins manually (Table 33.4 Compatibilities, pg 556-557 mixing of insulins) Bolus prior to meals Sliding scale insulin: Dosing Methods Dosage is ordered in a “sliding” amount that increases as blood glucose increases. Basal-bolus insulin: Mimics a healthy pancreas by delivering basal insulin (long acting glargine). Bolus’ are given as needed (lispro or aspart). Used for type 2 diabetes. Antidiabetic Drugs: Oral Antidiabetic Medications Effective treatment involves several elements: Lifestyle changes, blood glucose monitoring, drug therapy, trmt of comorbid conditions such as HTN. *IMP NOTE: The pancreas must be producing some insulin for an oral hypoglycemic to work. Biguanide Sulfonylureas Thiazolidinesdiones α – Glucosidase inhibitors Dipeptidyl Peptidase 4 ihibitors Sodium-glucose cotransporter 2 inhibitor Biguanide: Metformin (Glucophage). First-line drug and the most commonly used oral medication for the treatment of type 2 diabetes. Mechanism of action: decrease hepatic glucose production. Contraindications: Kidney disease, alcoholism, liver disease, HF. Adverse effects GI effects such as abdominal bloating and cramping, nausea Metallic taste, hypoglycemia, and a reduction in vitamin B12 levels after long-term use. Oral Antidiabetic Drugs: Metformin Gliclazide, glimepiride, glyburide Oral Antidiabetic Drugs: Sulphonylureas Indications: 2nd step drug used with metformin if metformin alone does not give good control. Releases insulin stores from the pancreas. Contraindications: hypoglycemia, advanced age, alcohol use. Adverse effects: hypoglycemia, weight gain, skin rash, nausea, epigastric fullness, and heartburn. Pioglitazone (Actos) Insulin-sensitizing drugs. Work to reduce insulin resistance by enhancing sensitivity of insulin receptors Third major drug category for oral treatment. Oral Antidiabetic Drugs: Thiazolidinediones Slow onset and peak – due to this they are typically only used in patients who cannot tolerate other first and second line treatments Contraindications: Heart failure, liver/kidney disease Adverse Effects: peripheral edema, weight gain, increased risk of fractures Oral Antidiabetic Medications Dipeptidyl peptidase 4 (DPP-4) inhibitors (gliptins) Sitagliptin (januvia) Saxagliptin (onglyza) Increase insulin synthesis and lower glucagon secretion. Adverse Effects: URTI, headache, & diarrhea Sodium Glucose Cotransporter 2 Inhibitors New antihyperglycemic drugs canagliflozin and dapaglifloxin. Prevent glucose reabsorption in the Kidney – voided out in urine. Adverse Effects: Vaginal yeast infections, UTI, hyperkalemia Diabetes: Hypoglycemia Abnormally low blood glucose level (below 4 mmol/L) Mild cases can be treated with diet—higher intake of protein and lower intake of carbohydrates—to prevent rebound postprandial hypoglycemia. Symptoms Anxiety, tremors, sensation of hunger, palpitations, sweating, Difficulty concentrating, confusion, weakness, drowsiness, vision changes, Used to treat hypoglycemia: below 4 mmol. S&S: anxiety, tremors, hunger, sweating, confusion, vision changes, headache, hypothermia, coma and possibly death. GlucoseElevating Drugs Oral forms: Gel, liquid, or tablet form. 50% dextrose in water (D50W) for IV Glucagon Nursing Implications V/S and current glucometer reading. Can the patient eat after administration or are they NPO or is there N/V? Trauma, pregnancy, stress, infection and steroid use may increase blood glucose levels. Assess for ability to self-administer insulin or oral drugs. Insulins must be checked by 2 nurses before administration. Oral antidiabetic drugs: Always check blood glucose levels before administering. Usually given 30 minutes before meals Metformin is taken with meals to reduce GI effects. Hold metformin if contrast dye tests are to be performed Nursing Implications: Insulins Check blood glucose level before giving insulin. Roll vials between hands instead of shaking them. Only use insulin syringes, calibrated in units. Ensure correct timing of insulin dose with meals – HYPOGLYCEMIA is a major risk once insulin is given. When drawing up two types of insulin in one syringe, always withdraw the regular or rapid-acting (clear) insulin first. Provide thorough patient education regarding self-administration of insulin injections, including timing of doses, monitoring of blood glucose levels, and injection site rotations. If hypoglycemia occurs: Administer oral form of glucose if the patient is conscious. Deliver D50W or IV glucagon if the patient is unconscious. Monitor blood glucose levels. Hypoglycemia Alcohol and hypoglycemia: while the liver is busy processing alcohol, it stops releasing stored glucose into the bloodstream, contributing to or precipitating hypoglycemia. Monitor for therapeutic response Monitor blood glucose and HbA1c Monitor for adverse effects