Lec 21: Endocrine: Pituitary, Thyroid, Adrenal Drugs

Lec 21

Agonist =

Substance that activates a receptor in the body

• Typically mimicking the action of a naturally occuring substance

Antagonist =

A substance that blocks or inhibits the activity of a receptor in the body

Hypothalamic agents: uses?

• Antagonist to growth hormone releasing hormone (GHRH)

• Antagonist for gonadotropin releasing hormone (GnRH)

Anterior pituitary agents: Agonists

• S

• Hormone analogue

• Indication

• Somatotropin

• GH

• Growth failure, AIDS-related conditions

Anterior pituitary agents: Agonist

• C

• Hormone analogue

• Indications

• Cosyntropin

• ACTH
  Assess adrenal function

Anterior pituitary agents: Antagonists

• P

• Hormone target

• Indication

• Pasireotide

• ACTH/GH

• Cushing disease / Acromegaly

Anterior pituitary agents: Antagonists

• O

• Hormone target

• Indication

• Ocreotide

• GH

• Acromegaly

Posterior Pituitary agents: Agonist

• D

• Hormone Analogue

• Indications

• Desmopressin

• ADH

• Neurogenic diabetes insipidus

Posterior Pituitary agents: Antagonist

• C

• Hormone Target

• Indications

• Conivaptan

• ADH

• Hyponatremia

Somatotropin: Class

Growth hormone agonist

Somatotropin: Action

• Mimics GH effects binding to receptors on target cells (bones, skeletal muscles, liver)

• Increased protein synthesis; Increased carb metabolism; Lipid mobilization; Retention of sodium/phosphorous/potassium

• Stimulates IGF-1 production → Further stimulate cellular growth

Somatotropin: Indications?

• Growth failure in children due to deficiency of GH

• Children with short stature born small for gestational age with no catch up growth by age 2

• Children with idiopathic short stature

• GH Deficiency in adults becuase of disease / trauma

Somatotropin: Therapeutic effetcs?

Skeletal growth

Somatotropin: Side effects?

• Edema

• Hypothyroidism

• Decreased insulin sensitivity

• HA

• Upper respiratory tract infection

• Neuromuscular pain

Somatotropin: Contraindications?

• Active malignancy

• Closed growth plates inchildren

Somatotropin: Interactions?

• Glucocorticoids (decreases effects)

• Insulin (may need higher dose)

Somatotropin: Pt education?

• Rotate SUBQ injection site

• Administer in evening

• Avoid in elderly

• Monitor blood glucose + thyroid function

• Monitor growth trajectory

• Report knee / hip pain

Octreotide: Therapeutic class?

Growth hormone antagonist

Octreotide: Pharmacological class?

Somatostatin analog

Octreotide: Action?

• Suppresses GH, Insulin, Glucagon

• Suppresses secretion of serotonin and gastric enterohepatic peptides

• Increases absorption of fluid + electrolytes from the GI tract and increases transit time

Octreotide: Indications?

• Acromegaly

• Diarrhea

• Neuroendocrine tumors

Octreotide: Therapeutic effects?

Normalized GH + IGF-1

Octreotide: Side effects?

• CV: HTN, Bradycardia

• Derm: Increased sweating

• EENT: Sinusitis

• Endo: Hyperglycemia

• GI: Cholelithiasis, Ileus, Pancreatitis

• MS: Arthralgia

• Neuro: HA

Octreotide: Contraindications?

Hypersensitivity

Octreotide: Interactions?

• Decreased efficacy of hormonal contraceptives

• May increase glucose effects with any medication altering glucose

Octreotide: Pt teaching?

• Monitor bowel sounds

• Monitor glucsoe

• Monitor pulse + BP

• Report abdominal pain

• May alter absorption of fats; administer on empty stomach or 1 hour before - 2 hours after meal

Desmopressin: Therapeutic class?

Antidiuretic hormone (ADH))

Desmopressin: Pharmacological class?

Vasopressin analog

Desmopressin: Action?

• Binds to V2 receptors in renal collecting ducts to increase water reabsorption and reduce urine output (more concentrated)

  • Increase ADH levels

• Stimulates clotting factor

Desmopressin: Indications

• Diabetes insipidus

• Nocturnal enuresis

• Hemophilia A

Desmopressin: Therapeutic effects?

• Decreased urine output

• Decreased thirst

Desmopressin: Side effects?

• Dry mouth

• Hyponatremia

• DIzziness / HA

• HTN

Desmopressin: Contraindications?

• Hyponatremia

• Moderate to severe kidney impairment

• Use in older adults

Desmopressin: Interactions?

• Loop diuretics (severe risk of hyponatremia)

• Steroids (Severe risk of hyponatremia)

Desmopressin: Nursing implications?

• Monitor serum sodium, urine + plasma osmolality + urine volume

• Assess pt for symptoms of dehydration

• Weigh pt daily + assess for edema

• Carefully monitor fluid intake

Levothyroxine: Therapeutic class

Hormones

Levothyroxine: Pharmacological class

Thyroid agent

Levothyroxine: Action

Mimic endogenous T4 hormone

Levothyroxine: Indications

• Hypothyroidism

  • Primary

  • Iatrogenic

Levothyroxine: Therapeutic effects

• Reduced hypothyroidism symptoms

  • Relieve constipation, depressed mood, dry skin, irregular periods, weight loss, fatigue

Levothyroxine: Side effects?

• HA

• Insomnia

• Nervousness

• Tachycardia/palpations

• Weight loss

• Excessive sweating/heat intolerance

• Cardiac arrest

Levothyroxine: Contraindications?

• Hyperthyroidism

• Recent MI

• Adrenal insufficiency

• Caution in pt with dysrhythmias

Levothyroxine: Interactions?

• Calcium, Iron

• Bile acid sequestrants

• Warfarin

Levothyroxine: Pt teaching?

• Take medicaion 1 hour before eating

• Takes several weeks to reach therapeutic levels

• Do not stop taking abruptly; life long therapy

• Take calcium/iron containing drugs 3-4 hours after levo

• Monitor for signs of hyperthyroidism

• Monitor TSH, T3, T4 for drug efficacy

Methimazole: Therapeutic class

Antithyroid

Methimazole: Pharmacological class

Antithyroid agent

Methimazole: Action

• Inhibits thyroid peroxidase enzyme → Blocks formation of T3/T4

• Does not affect already made T4

Methimazole: Indications?

• Hyperthyroidism

• Graves disease

Methimazole: Therapeutic effects

Reduction in hyperthyroid symptoms

Methimazole: SIde effects

• Skin rash

• HA

• GI disturbances

• Drowsiness

• More serious

  • Agranulocytosis (fever, sore throat, flu)

  • Hepatic toxicity

  • Bradycardia

Methimazole: Contraindications

• First trimester pregnancy

• Liver dysfunction

• Bone marrow suppression

• Taking with iodine

Methimazole: Interactions

• Warfarin (reduce efficacy)

• Beta blockers (effects change once thyroid function back in range)

• Foods high in iodine

Methimazole: Pt teaching

• Take same time everyday

• If considering pregnancy, medication is contraindicated in first trimester + breastfeeding

• Report unexplained fever, flu like symptoms, reduced urine output or yellowing skin

• Avoid taking with high iodine foods

• Will take 1-3 weeks to see effects

Methimazole: Monitor

• Liver enzymes

• TSH, T3, T4

• WBC

Fludrocortisone: Therapeutic class

Mineralcorticoid replacement therapy

Fludrocortisone: Pharmacological class

Mineralcorticoid

Fludrocortisone: Action

• Mimic aldosterone

  • Increase water + sodium

  • Excrete potassium

• Also has glucocorticoid effects

Fludrocortisone: Indications

• Addisons disease

• Adrenal insufficiency

Fludrocortisone: Therapeutic effects

• Improved fluid volume, sodium levels, reduced symptoms

Fludrocortisone: Side effects

• HTN

• Edema

• HA

• Insomnia

• Hypokalemia

• Cushing syndrome

• Fluid overload

Fludrocortisone: Contraindications

• Use with fungal infections

• Use with caution in elderly, diabetes, kidney disease

Fludrocortisone: Interactions

• Desmopressin (hyponatremia risk)

• Loop diuretics (hypokalemia risk)

• Thiazide diuretics (hypokalemia risk)

• Live vaccines

Fludrocortisone: Pt teaching

• Take medication as prescribes, do not stop abruptly

• Monitor for signs of fluid retention and electrolyte imbalance

• Dosage may need to be adjusted during times of illness

Fludrocortisone: Monitor

• Daily weight for fluid status

• Signs of hypokalemia

• Signs of fluid overload

Pasireotide: Therapeutic class

Pituitary hormone suppressant

Pasireotide: Pharmacological class

Somatostatin analog

Pasireotide: Action

Suppresses ACTH secretion → Decreased cortisol production

Pasireotide: Indications

• Cushings disease when surgery is not an option

• Acromegaly

Pasireotide: Therapeutic effetcs

Reduced cortisol and associated symptoms

Pasireotide: Side effetcs

• A lot

• Hyperglycemia

• DM

• Cardiac rhythm abnormality

Pasireotide: Contraindications

• Uncontrolled diabetes

• Patients at high risk for cardiac dysrhythmias

Pasireotide: Interactions

• Medications that influence blood glucose levels

• Increase risk for QT prolongation

• Cause bradycardia

Pasireotide: Pt teaching

• Monitor for signs of hyperglycemia

• Report signs of gallstones

• Monitor for signs of adrenal insufficiency

Pasireotide: Monitoring

• Cortisol levels

• Liver enzymes

• Electrolytes (potassium) to reduce risk of dysrhythmias

Pasireotide: Administration

• IM injection into gluteus muscle every 4 weeks

  • 90 degrees