Endocrine Drugs Study Notes

Endocrine Drugs

Drug List

  • Desmopressin (DDAVP)
  • Levothyroxine
  • Methimazole
  • Glucocorticoids
  • Insulin
    • Rapid-acting
    • Short-acting
    • Intermediate-acting
    • Long-acting
    • Combination
  • Sulfonylureas
    • Glipizide
    • Glimeperide
  • Biquanides
    • Metformin
  • Meglitinides
    • Repaglinide
    • Nateglinide
  • Incretin Agents
    • GLP1
      • Exenatide
      • Liraglutide
    • DPP-4
      • Sitagliptin
      • Saxagliptin
  • SGLT2 Inhibitors
    • Canagliflozin
    • Dapagliflozin
    • Empagliflozin

Pituitary Gland

  • Stores hormones made by the hypothalamus.
  • Hormones are responsible for a number of functions.
  • Anterior Pituitary Hormones:
    • Growth hormone
    • Prolactin
    • Luteinizing hormone (LH)
    • Follicle-stimulating hormone (FSH)
    • Adrenocorticotropic hormone (ACTH)
    • Thyroid-stimulating hormone (TSH)
  • Posterior Pituitary Hormones:
    • Vasopressin (ADH)
    • Oxytocin

Pituitary Gland: Desmopressin (DDAVP)

  • Antidiuretic hormone
  • Desmopressin (DDAVP) is administered IV or PO.
  • Mechanism of action:
    • Produced endogenously to promote renal conservation of water.
    • This synthetic analog exerts an antidiuretic effect.
  • Place in therapy:
    • Useful in the treatment of diabetes insipidus (DI), a disease where the pituitary cannot produce or secrete ADH.
    • Related to brain injuries.
    • Associated with large amounts of dilute urine.
    • DDAVP can also be used to treat nocturnal enuresis.
  • Adverse Effects:
    • Hyponatremia
    • Hypertension

Nursing Process: Pituitary Disorders

  • Assessment:
    • Obtain baseline vital signs for future comparison.
    • Report abnormal results.
    • Determine patient's urinary output and weight (strict I’s and O’s).
  • Planning:
    • Patient will be free from pituitary disorder with appropriate drug regimen.
  • Nursing Interventions/Evaluation:
    • Monitor vital signs.
    • Record urinary output.
    • Monitor electrolytes.

Thyroid Gland

  • Thyroid gland hormones
    • Thyroxine (T4) inactive (precursor to T3)
    • Triiodothyronine (T3) active
  • Functions
    • Regulate metabolism controlling how the body uses energy, effects processes such as heart rate, body temperature, and calorie burning.

Thyroid Function Tests

  • Serum thyroid-stimulating hormone (TSH)
    • Screening and diagnosis of hypothyroidism
    • Elevated TSH is indication of hypothyroidism
  • Serum T4 test
    • Can measure total T4 or free T4
  • Serum T3 test
    • Can measure total T3 or free T3

Thyroid Gland: Hypothyroidism

  • Hypothyroidism
    • Decrease in thyroid hormone secretion
  • Etiology
    • Primary: Lack of thyroid hormone based on thyroid gland disorder
      • Common causes include the following
        • Thyroid gland inflammation/Hashimoto’s Thyroiditis
        • Iodine deficiency
        • Surgery
    • Secondary: lack of thyroid hormone based on pituitary gland or hypothalamus
  • Common Symptoms:
    • Thickened, dry skin
    • Hair loss
    • Constipation
    • Lethargy
    • Hypothermia
    • Bradycardia

Drug Therapy: Hypothyroidism

  • Levothyroxine sodium (Synthroid)
    • Place in therapy
      • Drug of choice for replacement therapy for the treatment of hypothyroidism
    • Mechanism of action
      • Increases the levels of T3 and T4
      • Increase metabolism, body growth
    • Contraindications
      • MI, acute
      • Hypersensitivity to drug or ingredient
    • Interactions
      • Increased effects of anticoagulants, TCAs, decongestants
      • Decreased effects of insulin and antidiabetics
      • Decreased effects of digoxin
      • Decreased efficacy when taken with food
      • Should be taken on an empty stomach
    • Side effects/adverse reactions
      • Nervousness, insomnia, weight loss
      • Tremors, headache
      • Nausea, vomiting, diarrhea, cramps
      • Tachycardia, palpitations, hypertension
      • Dysrhythmias, angina

Hyperthyroidism

  • Increase in circulating T4 and T3 levels
    • Graves disease, or thyrotoxicosis
      • Most common type of hyperthyroidism caused by hyperfunction of the thyroid gland
      • Characterized by tachycardia, palpitations, excessive perspiration, heat intolerance, nervousness, irritability, exophthalmos (bulging eyes), and weight loss
  • Treatment
    • Surgical removal of a portion of the thyroid gland
    • Radioactive iodine therapy
    • Antithyroid drugs, which inhibit either synthesis or release of thyroid hormone

Drug Therapy: Hyperthyroidism

  • Methimazole
    • Effective antithyroid drug
      • Mechanism of action
        • Inhibits thyroid hormone synthesis
      • Place in therapy
        • Useful for treating thyrotoxic crisis and in preparation for subtotal thyroidectomy
      • Interactions
        • Increase effect of anticoagulants
        • Decrease effect of antidiabetics
        • Digoxin and lithium increase action of thyroid drugs.
        • Phenytoin increases T3 level.
      • Adverse effects
        • Rash
        • Bradycardia
        • Thrombocytopenia
        • Leukopenia

Nursing Process: Thyroid Hormone Replacement Drugs

  • Assessment
    • Determine baseline vital signs for future comparison
    • Check serum T3, T4, and TSH levels
    • Obtain history of drugs patient currently takes. Be aware that thyroid drugs enhance action of oral anticoagulants, antidepressants and decrease action of insulin, oral hypoglycemics, and digitalis preparations
  • Nursing diagnoses
  • Planning
    • Patient's signs and symptoms of hypothyroidism will be alleviated within 2 to 4 weeks with prescribed thyroid drug replacement
  • Nursing interventions
    • Monitor vital signs, weight
    • Administer thyroid replacement drug before breakfast
    • Check labels before using OTCs
    • Advise reporting of symptoms of hyperthyroidism
  • Evaluation
    • Evaluate effectiveness of thyroid drug and drug compliance
    • Continue monitoring for side effects from drug accumulation or overdosing

Nursing Process: Antithyroid Drugs

  • Assessment
    • Determine baseline vital signs for future comparison
    • Check serum T3, T4, and TSH levels
    • Assess for signs and symptoms of thyroid crisis (thyroid storm), including tachycardia, cardiac dysrhythmias, fever, flushed skin, confusion, behavioral changes.
  • Nursing diagnoses
  • Planning
    • Patient's signs and symptoms of hyperthyroidism will be alleviated in 1 to 3 weeks with prescribed antithyroid drug
  • Nursing interventions
    • Administer antithyroid drugs with meals
    • Warn of iodine effects and presence in iodized salt, shellfish, and over-the-counter cough medications
    • Do not abruptly stop antithyroid drugs.
    • Advise reporting of symptoms of hypothyroidism
  • Evaluation
    • Evaluate effectiveness of antithyroid drug in decreasing signs and symptoms of hyperthyroidism

Hypothyroidism vs. Hyperthyroidism: Visual Comparison

  • Hypothyroidism (LOW & SLOW)
    • Dry hair
    • Cold intolerance
    • Puffy face
    • Goiter
    • Slow Heartbeat
    • Weight gain
    • Constipation
    • Possible infertility & risk of miscarriage along with irregular periods
    • Periods can occur less often or with longer cycles
  • Hyperthyroidism (HOT & HIGH)
    • Hair loss
    • Bulging eyes
    • Goiter
    • Heat intolerance
    • Fast Heartbeat
    • Weight Loss
    • Diarrhea

Glucocorticoids

  • Endogenously secreted in times of stress to increase energy available to the body
    • Increase in glucose availability
    • Increase breakdown of protein
    • Increase in lipogenesis (formation and storage of fat in the body to be used for energy)
    • Decrease in protein formation to conserve energy
    • Decrease in immune function to conserve energy
    • Reduce inflammation
    • Anti-inflammatory properties
  • Anti-inflammatory effects
    • Inhibit the formation of phospholipase A2
    • Phospholipase A2 is a precursor to arachidonic acid
    • Arachidonic acid is a precursor to inflammatory mediators cyclooxygenase 1 and 2
  • Most often used to treat an exacerbation of a chronic disease (ex. COPD) by suppressing the immune system
  • Could be used to treat multiple inflammatory conditions
  • Therapy must be tapered to prevent adrenal insufficiency
  • Formulations
    • Dexamethasone (Decadron)
      • Oral
      • Intravenous
    • Betamethasone (Beclovent)
      • Inhaled
    • Methylprednisolone (Medrol; Solu-Medrol; Depo-Medrol)
      • Oral
      • Intravenous
      • Intra-articular
    • Triamcinolone (Aristocort)
      • Topical
    • Prednisone (Deltasone)
      • Oral
    • Prednisolone (Delta-Cortef)
      • Oral
      • Opthalamic
    • Budesonide
      • Oral (Entocort EC)
      • Intranasal (Rhinocort)
    • Hydrocortisone (Cortef)
      • Topical
      • Oral
      • Intravenous
    • Fluticasone
      • Inhaled (Flovent, part of Advair)
      • Intranasal (Flonase)
  • Indications
    • Local treatment
      • Asthma/ COPD
        • Inhaled glucocorticoids
      • Inflammatory conditions involving joints
        • Intra-articular glucocorticoids
      • Ophthalmic swelling
        • Intravitreal glucocorticoids
        • Glucocorticoid eye drops
      • Inflammatory conditions involving the nose
        • Intranasal glucocorticoids
      • Rashes/ hives
        • Topical glucocorticoids
    • Systemic treatment
      • Asthma/ COPD
        • Oral/ intravenous glucocorticoids
      • Rashes/ hives
        • Oral/ intravenous glucocorticoids
      • Cancer
        • Oral/ intravenous glucocorticoids
      • Rheumatoid arthritis
        • Oral/ intravenous glucocorticoids
      • Inflammatory disorders of the GI tract (Crohn’s, UC )
        • Oral/ intravenous glucocorticoids
      • Immune-mediated disorders of the CNS
        • Oral/ intravenous glucocorticoids
  • Side effects/adverse reactions
    • Increased appetite
    • Infection
      • Secondary to immunosuppression
    • Mood changes
    • Hyperglycemia
      • Secondary to increased glucose availability
    • Poor wound healing/ muscle wasting
      • Secondary to increase protein breakdown
    • Peptic ulcers
      • Secondary to “good” prostaglandin inhibition
  • Interactions
    • Increases effect of phenytoin, theophylline
    • Decreased effects of antidiabetics

Nursing Process: Glucocorticoids

  • Assessment
    • Note baseline vital signs for future comparison
    • Assess laboratory test results, especially serum sodium, serum potassium and blood sugar
  • Nursing diagnoses
    • Knowledge of necessity for tapering off medication
    • Excess fluid volume related to fluid retention
  • Planning
    • Patient's side effects of glucocorticoid therapy will be minimal
    • Patient's inflammatory process will decrease
  • Why tapering doses is important
    • When taking steroids over an extended time period, the body’s natural cortisol production decreases because the adrenal glands get less active due to the external supply from the steroid medication.
    • Abruptly stopping can lead to adrenal crisis as it causes suppression of the adrenals, making them unable to produce enough cortisol when needed. Potentially causing a life threatening situation.
  • Nursing interventions
    • Determine vital signs. Glucocorticoids such as prednisone can increase blood pressure via sodium and water retention
    • Monitor laboratory values, especially serum electrolytes and blood glucose
    • Patient teaching
      • Advise patient to take drug as prescribed. Caution patient not to abruptly stop drug
      • Teach patient to avoid persons with respiratory infections, because these drugs suppress immune system
  • Evaluation
    • Evaluate effectiveness of glucocorticoid therapy. If inflammation has not improved, change in drug therapy may be necessary
    • Continue monitoring for side effects, especially when patient is receiving high doses of glucocorticoids.

Insulin

  • Released from beta cells of islets of Langerhans in pancreas
  • Responds to increase in blood glucose
    • Function
      • Promotes uptake of glucose, amino acids, and fatty acids
      • Converts to glycogen for future glucose needed in liver and muscle
  • Diabetes ”control” is evaluated by:
    • Blood glucose (short term control)
    • Hemoglobin A1C (long term control)
      • A1C 5.7-6.4% indicates prediabetes; >6.5% indicates diabetes
  • Insulin can be given in two forms: basal and bolus.

Insulin Types

  • Rapid-acting
  • Short-acting
  • Intermediate-acting
  • Long-acting
  • Combinations
  • Rapid-acting insulin (clear; bolus insulin)
    • Insulin lispro (Humalog), Insulin aspart (NovoLog)
      • Onset of action (5 to 15 minutes)
      • Peak (30 minutes to 1 hour)
      • Duration (2 to 4 hours)
      • Given 5-15 min before meals and snacks when food is in front of patient
  • Short-acting insulin (clear; bolus insulin)
    • Regular
      • Onset of action (30 to 60 minutes)
      • Peak (2 to 3 hours)
      • Duration (3 to 4 hours)
      • Given 30 min before meals and snacks
  • Intermediate-acting (cloudy; basal insulin)
    • Insulin NPH (Humulin N, Novolin N)
      • Onset of action (2 to 4 hours)
      • Peak (4 to 12 hours)
      • Duration (18 to 24 hours)
      • Given twice daily
  • Long-acting (basal insulin)
    • Insulin glargine (Lantus)
      • Onset of action (1 hour)
      • Duration (24 hours)
      • Administered at bedtime
  • Combinations
    • Composed of short- and intermediate-acting or rapid- and intermediate- acting
    • Used to decrease administration frequency and cost
    • Examples include
      • Humulin 70/30 (NPH 70%, regular 30%)
      • Considered “basal and bolus” insulin
  • Sliding-scale insulin coverage
    • Adjusted doses dependent on individual blood glucose
    • Example: If blood sugar is between 150-200 mg/dL, 2 units of insulin would be administered
    • If blood glucose is between 201-250 mg/dL, 4 units would be administered
    • Usually done before eating meals and snacks
    • Uses rapid or short-acting insulin
  • Storage of insulin
    • Keep in refrigerator
    • Opened insulin vials can be stored outside refrigeration for 1 month
    • Remove from refrigerator 30 minutes before injection
    • Avoid storing insulin in direct sunlight or at high temperatures

Nursing Process: Insulin

  • Assessment
    • Identify the drugs patient currently takes. Some medications increase and decrease blood glucose levels
    • Assess the type of insulin and dosage. Note whether it is given once or multiple times a day
    • Note vitals including blood glucose level
    • Check for signs and symptoms of hypoglycemic reaction, hyperglycemia, or ketoacidosis
  • Nursing diagnosis
    • Risk for impaired skin integrity related to failure to rotate insulin injection sites
    • Imbalanced nutrition
  • Planning
    • Patient's blood glucose will be within normal values (70 to 110 mg/dL).
    • Patient will self-administer insulin correctly.
  • Nursing interventions
    • Monitor vital signs. Tachycardia can occur during insulin reaction (hypoglycemia).
    • Determine blood glucose levels, and report changes.
    • Monitor patient’s hemoglobin A1C
    • Patient teaching
      • Teach patient to recognize and immediately report symptoms of hypoglycemic (insulin) reaction
      • Orange juice can be used to reverse hypoglycemia
      • Teach patients to recognize hyperglycemic reaction (diabetic acidosis) characterized with thirst, increased urine output, and sweet, fruity/chemical breath odor
      • Advise patient to carry a MedicAlert card, tag, or bracelet
  • Evaluation
    • Evaluate effectiveness of insulin therapy by noting if blood sugar level is within accepted range
    • Acute glucose control is measure with serum blood sugar
    • Chronic or long term glucose control is measured with hemoglobin A1C

Oral Antidiabetic Drugs

  • First-second- and third generation sulfonylureas
    • Differences in generations
      • Potency (3rd > 2nd > 1st )
      • Presence of cardiovascular side effects (1st >2nd > 3rd )
    • First-generation sulfonylureas
      • Short-acting: tolbutamide (Orinase)
      • Intermediate-acting: tolazamide (Tolinase)
      • Long-acting: chlorpropamide (Diabinese)
    • Second-generation sulfonylurea
      • Glipizide (Glucotrol, Glucotrol XL)
    • Third-generation sulfonyurea
      • Glimepiride (Amaryl)

Sulfonylureas

  • Mechanism of action:
    • Stimulates release of insulin from the beta cells of pancreas
  • Therapeutic use:
    • Type II diabetes
  • Adverse effects:
    • Hypoglycemia
      • Must be given if patients consuming routine amount of calories
      • If intake is less, dose should be held
    • Cardiovascular toxicity (1st generation)…no longer in use

Oral Antidiabetic Drugs: Nonsulfonylureas

  • Biguanide: Metformin (Glucophage)
    • Action
      • Decreases hepatic production of glucose from stored glycogen
      • Decreases the absorption of glucose from the small intestine
      • Diminishes the increase in serum glucose following a meal, thereby blunting the degree of postprandial hyperglycemia
      • Increases insulin receptor sensitivity.
      • Hypoglycemia is rare due to mechanism of action
  • Therapeutic uses:
    • Type II diabetes treatment
  • Adverse effects:
    • Mild – GI intolerance(diarrhea), bitter aftertaste (low and slow)
    • Severe - Lactic acidosis associated with accumulation
  • Contraindications
    • Use should be avoided in patients with kidney injury (based on GFR)
    • Use should be avoided in patients >80 years of age due to decreased renal function
    • Hold before and after imaging with contrast.
  • Drug interactions
    • Contrast
  • Monitoring
    • Blood glucose; A1C
    • Lactic acid level
    • Serum creatinine

Meglitinides

  • Examples include:
    • Repaglinide (Prandin)
    • Nateglinide (Starlix)
  • Mechanism of action:
    • Short acting agent to stimulate beta cells to produce insulin when glucose is elevated
    • Works best when taken with food!
  • Therapeutic use:
    • Type II diabetes
  • Duration of action:
    • 3 hours
    • Take with or before meals, skip if no meal
  • Adverse effects:
    • Hypoglycemia
    • N/V/D
    • Myalgias
    • Headache
  • Monitoring parameters:
    • Should only be administered during mealtimes

Incretin Agents

  • Mechanism of action
    • Activate glucagon like peptide-1 (GLP-1) receptor which then increases insulin secretion and decreases glucagon secretion. Also they delay gastric emptying.
    • Insulin stimulating effect is strictly glucose dependent

GLP-1 Agonists

  • Examples include (given subcutaneously)
    • Exenatide (Byetta)
    • Liraglutide (Victoza)
  • Adverse effects
    • Common
      • Hypoglycemia, GI upset.
    • Serious
      • Acute kidney injury, pancreatitis, cholecystitis
  • Drug-drug interactions
    • May increase INR in patients receiving warfarin
    • May increase acetaminophen levels

Incretin Modifiers: DPP 4 Inhibitor

  • Examples include the following:
    • Sitagliptin phosphate (Januvia)
    • Saxagliptin (Onglyza)
  • Mechanism of action
    • Similar to GLP 1 but initiates its action by inhibiting dipeptidyl peptidase 4 (enzyme that inacives GLP-1)
    • Increase the level of incretin hormones thereby increasing insulin secretion, and decreasing glucagon secretion.
  • Adverse effects
    • Hypoglycemia
    • GI upset
    • Rare increased risk of pancreatitis
    • Respiratory tract infection (may suppress the immune system?)

SGLT2 Inhibitors

  • Mechanism of action
    • SGLT2- inhibits sodium-glucose cotransporter (SGLT2); reducing glucose and sodium reabsorption, increasing urinary glucose excretion and sodium delivery back to distal tubules
  • Examples include the following:
    • Canagliflozin (Invokana)
    • Dapagliflozin (Farxiga)
    • Empagliflozin (Jardiance)
  • Adverse effects
    • Common-genital yeast infection, increased cholesterol, UTI
    • Serious-acute kidney injury, UTI-serious, pancreatitis