Transcript Chapter 48 Antidysrhythmic Drugs

Drugs for Thyroid
Disorders
Chapter 58
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Thyroid Hormone Actions
Stimulation of energy use
Stimulation of the heart
Promotion of growth &
development
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Thyroid
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Figure 58-2 Steps in thyroid hormone synthesis.
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Hypothalamus – Releasing
Factors
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Figure 58-3 Regulation of thyroid function.
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Lab Tests
• Thyroid Stimulating Hormone is the best
test of thyroid function
• Except in the case of…
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Thyroid Problems
Hypo
• Cold skin
• Dry skin & hair
• Low HR
• Lethargy
• Weight gain
• Cold intolerance
Hyper
• Increased body temp
• Skin warm & moist
• Elevated HR
• Nervous, insomnia
• Weight loss
• Increased appetite
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Hypothyroidism
• Severe deficiency of thyroid hormone
– Myxedema (adults)
– Cretinism (infancy)
• Top Causes
– Autoimmune (Hashimoto’s thyroiditis)
– Iodine deficiency
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Hypothyroidism (cont’d)
• Therapeutic strategy
– Levothyroxine (T4)
– Liothyronine (T3)
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Thyroid Hormone Preparations
• Levothyroxine (T4) [Synthroid]
– Synthetic preparation of thyroxine (T4)
– Conversion to T3
– Half-life is 7 days
– Used for all forms of hypothyroidism
– Adverse effects
can you anticipate what these might
be?
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Hypothyroidism (cont’d)
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Therapeutic goal?
When to dose?
When to recheck TSH?
What happens to dosing in pregnancy?
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Hyperthyroidism
• Two major forms of hyperthyroidism
– Graves’ disease (most common)
– Toxic nodular goiter (Plummer’s
disease)
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Hyperthyroidism (cont’d)
• Cause of Grave’s disease
– Thyroid-stimulating immunoglobulins (TSIs)
• Treatment
– Suppression of thyroid hormone synthesis
– Surgical removal of thyroid tissue
– Destruction of thyroid tissue
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Propylthiouracil (PTU)
• Inhibits thyroid hormone synthesis
• Short half-life (about 75 minutes)
• Therapeutic uses
– Graves’ disease
– Adjunct to radiation therapy
– Preparation for thyroid gland surgery
• Adverse effects
– Agranulocytosis
– Hypothyroidism
Caution in Pregnancy and lactation
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Methimazole
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First line drug
Inhibits thyroid hormone synthesis
Is safer and more convenient than PTU
Is contraindicated during pregnancy and
breastfeeding
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Radioactive Iodine-131 (131I)
• Radioactive isotope of stable iodine
• Emits gamma and beta rays
• Half-life is 8 days
• Used in Graves’ disease
• Action
– Produces clinical remission with
destruction of thyroid gland
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Exophthalmos & Goiter
Which is hypothyroid and which is
hyperthyroid?
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Case
A 25-year-old, previously healthy woman
presents with 1 month of anxiety,
palpitations, loose stools, fine tremors, and
hair loss. 20-pound weight loss over past 4
months, increased appetite. HR 115 to 130
BPM, T 37.5C. Exam notable for mild
bilateral proptosis, thin hair, and moist skin.
Goiter visible with audible bruit.
Hyperreflexia and fine tremors. EKG –
normal sinus tachycardia.
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Question
When caring for a client in thyroid crisis
(storm), the nurse would question an order
for…
• IV Fluids
• Propranolol
• PTU
• Hyperthermia (warming) blanket
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Question
A client is prescribed Synthroid daily. The most
important instruction to give her is…
• Taper dose & dc if mental and emotional
statuses stabilize.
• Take it at bedtime to avoid side effects of
nausea and flatus.
• Call the doctor immediately at the onset of
palpitations or nervousness.
• Decrease intake of juices and fruits with high
potassium and calcium contents.
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Drugs for Disorders
of the Adrenal Cortex
Chapters 60 & 72
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Physiology of the Adrenocortical
Hormones
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Three classes of steroid hormones
– Glucocorticoids- cortisol
– Mineralocorticoids- aldosterone
– Androgens- androstenedione
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Glucocorticoids—Physiologic
Effects
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Carbohydrate metabolism
Protein metabolism
Fat metabolism
Cardiovascular system
Skeletal muscle
Central nervous system
Stress
Respiratory system in neonates
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Figure 60-2 Negative feedback regulation of glucocorticoid synthesis and secretion.
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Adrenocortical Hormones
• Mineralocorticoids
– Circulatory balance
– Retention of sodium
(Na+) & water
– Excretion of potassium
(K+)
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Physiology of the Adrenocortical
Hormones
• Two most familiar forms of
adrenocortical dysfunction
– Adrenal hormone excess
• Cushing’s syndrome
– Adrenal hormone deficiency
• Addison’s disease
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Cushing’s syndrome
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Adrenal Hormone Excess
• Cushing’s syndrome
– Causes
• Hypersecretion of
adrenocorticotropic hormone
(ACTH)
• Hypersecretion of
glucocorticoids
• Administering glucocorticoids in
large doses
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Adrenal Hormone Excess
(cont’d)
• Cushing’s syndrome (cont’d)
– Treatment
• Surgical removal of the
adrenal gland
• Replacement therapy
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Adrenal Hormone Insufficiency
Addison’s disease
Primary Adrenocortical Insufficiency –
 Causes
- most often caused by autoimmune
disease
Acute adrenal insufficiency (adrenal crisis)
• Causes
– Adrenal failure
– Pituitary failure
– Inadequate doses of corticosteroids
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Adrenal Hormone Insufficiency
Addison’s disease
Symptoms
• Hypoglycemia
• Malaise
• Loss of appetite
• Reduced capacity to respond to stress
Treatment
• Rapid replacement of fluid, salt, and glucocorticoids
• Hydrocortisone is the drug of choice
– Increase in time of physiologic stress – 3x3 rule
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Hydrocortisone
• Synthetic steroid
• Therapeutic uses
– Adrenal insufficiency
– Allergic reactions to inflammation to
cancer
• Adverse effects
– Adrenal suppression
– Cushing’s syndrome
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Glucocorticoids
Drug
Physiologic
dose
Nonendocrine
dose
Hydrocortisone
20-25 mg
Up to 240
mg (up to
800 mg in
MS!)
Prednisone
5-10 mg
Up to 60-80
mg
Dexamethosone
.25-.75 mg
Up to 9 mg
Relative
GC
efficacy
Relative
MC
efficacy
See Table 7.2
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Fludrocortisone [Florinef]
• Potent mineralocorticoid
• Therapeutic uses
– Addison’s disease
– Primary hypoaldosteronism
– Congenital adrenal hyperplasia
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Fludrocortisone [Florinef]
• Adverse effects
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Hypertension
Edema
Cardiac enlargement
Hypokalemia
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Glucocorticoids in
Nonendocrine Diseases
• Glucocorticoid physiology
– Metabolic effects
– Cardiovascular effects
– Effects during stress
– Effects on water and electrolytes
– Respiratory system in neonates
Physiologic vs. Pharmacologic doses
What is the difference?
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Pharmacology of the
Glucocorticoids
• Effects on metabolism and electrolytes
• Anti-inflammatory and immunosuppressant
effects
• Therapeutic uses in nonendocrine
disorders
– Rheumatoid arthritis
– Systemic lupus erythematosus
– Inflammatory bowel disease
– Miscellaneous inflammatory disorders
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Pharmacology of the
Glucocorticoids (cont’d)
• Therapeutic uses in nonendocrine disorders
(cont’d)
– Allergic conditions
– Asthma
– Dermatologic disorders
– Neoplasms
– Suppression of allograft rejection
– Prevention of respiratory distress
syndrome
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Pharmacology of the
Glucocorticoids (cont’d)
• Adverse effects
– Adrenal insufficiency
– Osteoporosis
– Infection
– Glucose intolerance
– Myopathy
– Fluid and electrolyte disturbance
– Growth retardation
– Psychologic disturbances
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Pharmacology of the
Glucocorticoids (cont’d)
• Adverse effects (cont’d)
– Cataracts and glaucoma
– Peptic ulcer disease
– Iatrogenic Cushing’s syndrome
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Pharmacology of the
Glucocorticoids (cont’d)
• Development of adrenal suppression
– Exogenous vs. endogenous
• Adrenal suppression and physiologic stress
• Glucocorticoid withdrawal
– Taper the dosage over 7 days
– Switch from multiple doses to single doses
– Taper the dosage to 50% of physiologic
values
– Monitor for signs of insufficiency
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Question
A nurse knows the clinical manifestations of
a client with Addison’s disease include…
•Weight gain
•Hypertension
•Melanosis
•Hypotension
•Hyponatremia
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Question
A nurse knows the clinical manifestations of
a client with Addison’s disease include…
• Weight gain
• Hypertension
• Melanosis
• Hypotension
• Hyponatremia
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