Summary Nur 354 Exam 4 Study Guide

MODEL 7
NUR354
CHAPTERS 44 & 45

CHAPTER 44
Endocrine System
oMaintains homeostasis using hormones as chemical messengers
Secreted in response to changes in internal environment
oHormone release commonly controlled by negative feedback
oOne hormone may control another
Negative Feedback
oMECHANISM
oCommon for last hormone in a pathway to provide feedback
oExample
As serum calcium levels fall, PTH Is released
PTH causes an increase in serum calcium
Hormone Effects
oParathyroid
Stimulates osteoclasts
Raises serum calcium levels
Releases calcium from bones to circ
Increases absorption in GI tract
Calcitonin
Decreases calcium levels
Selected endocrine disorders and their pharmacotherapy
oGland: Parathyroid
Hormone: parathyroid hormone
Disorder: hypersecretion- hyperparathyroidism
oDrug therapy example: surgery (no drug therapy)
Disorder: hyposection- hypoparathyroidism
oHuman parathyroid hormone (Natpara), vitamin D and
calcium supplements
oGland: pituitary
Hormone: antidiuretic hormone
Disorder: hyposection: diabetes insipidus
oDrug therapy examples: desmopressin
Disorder: hypersection: syndrome of inappropriate antidiuretic
hormone (SIADH)- TOO MUCH ADH
Acromegaly
Octreotide (sandostatin)
Diabetes Insipidus
oDeficiency in ADH
oCharacterized by production of LARGE AMOUNTS OF VERY DILUTE URINE

, oIncreased thirst
oPolyuria
Pharmacotherapy of Diabetes Insipidus
oADH (antidiuretic hormone)
Conserves water in body
oDiabetes insipidus is caused by deficiency of ADH
Most common form of ADH: desmopression (DDAVP)
Long duration of action (20 hours)
Forms: nasal spray, oral, intravenous, subcutaneous
oDesmopressin or vasopressin and lypressin
Short duration of action (2-8 hours)
Usually given via intramuscular or IV routes
Also used to treat hemophilia
Where water goes, salt follows!
Monitor sodium levels!
Anterior pituitary agents
oPrototype drug; desmopressin
MOA: synthetic analog of human ADH, acts on the kidneys to increase
water reabsorption, contracts smooth muscle of vascular system, uterus,
and GI tract
Primary use: treatment of diabetes insipidus; also used for management
of bleeding patients with hemophilia A
Adverse effects: water intoxication, headache, nausea, mild abd pain,
hypertension, fluid overload (monitor BP and fluid intake!)
Thyroid gland
oSecretes thyroxine (T4) and tridothyronine (T3)
Control basal metabolic rate and affect every cell in body
oFollicular cells secrete and thyroid hormone
T4 and T3
Iodine essential for synthesis of T4 and T3
TSH stimulates release of T3 and T4
Negative feedback loop
Low thyroxine levels signal hypothalamus to release thyroid-
releasing hormone (TRH)
Single pituitary to release thyroid-stimulating hormone (TSH)
Symptoms of Hypothyroidism in Adults (Myxedema)
oEarly symptoms are general weakness, muscle cramps, and dry skin
oMore severe symptoms include:
Slurred speech, bradycardia, weight gain
Decreased sense of taste and smell
Intolerance to cold environments
oElevated TSH with diminished T3 and T4 levels
Hypothyroidism 9Myxedema)

, oLab studies
Elevated thyroid-stimulating hormone (TSH)
Decreased T3 and T4
Thyroid agents
oPrototype drug: levothyroxine
MOA: same as those of thyroid hormone
Primary use: drug of choice for replacement therapy in patients with low
thyroid function and Hashimoto
Serum TSH levels are regulary monitored to determine whether the
patient is receiving sufÏcient levothyroxine- high TSH levels usually
indicate that the dosage T4 needs to be increased. So if it working the
TSH will be low!
Adverse effects
Heat intolerance
Increases rate of all body systems!
May cause hot flashes and increased HR
Palpitations
Dysrhythmias
Anxiety
Insomnia
Weight loss
Admin alerts
Administer the medication at the same time every day, preferably
in the morning to decrease the potential for insomnia.
Take on empty stomach 30 minutes before breakfast
Pregnancy category A
Assess heart rate
Black box warning
Use of thyroid hormone in the treatment of obesity or weight loss
is contraindicated.
Indications
Levothyroxine increases the effects of warfarin, resulting in an
increased risk of bleeding
Hyperthyroidism
oMost common cause is Graves disease
oGoal is to lower metabolic activity of thyroid hormone
Avoid THYROID STORM
oTreatment
Administer thioamides, which decrease activity of thyroid gland
Propythiouracil (PTU), methimazole (Tapazole)
Radioactive iodide that kills overactive thyroid cells
Dosium iodide-131, Lugol’s solution (before surgery)
May become hypothyroid and need levothyroxine
Hyperthyroidism (Grave’s) Thyroid Storm