Thyroid & Parathyroid Agents Flashcards
What are the actions of the thyroid gland?
- Produces two thyroid hormones using iodine found in the diet (T3 & T4)
- Removes iodine from the blood, concentrates it, and prepares to for attachment to tyrosine, an amino acid
What are the functions of the thyroid hormone?
Regulate the rate of metabolism
Affect heat production and body temperature
Affect oxygen consumption, cardiac output, blood volume
Affect enzyme system activity
Affect metabolism of carbs, fats, and proteins
Regulate growth and development
What are the two types of thyroid dysfunction?
Hypothyroidism
Hyperthyroidism
Hypothyroidism is the under-activity of the thyroid
True
Hyperthyroidism is the overactivity of the thyroid
True
Low thyroid function causes high TSH
True
What is the normal range of TSH
.5-4.5
High thyroid function causes low TSH
True
Low TSH represents hyperthyroidism
True
What are the causes of hypothyroidism
Absence of the thyroid gland
Lack of sufficient iodine in diet to produce needed levels of thyroid hormone
Lack of sufficient functioning thyroid tissue due to tumor or autoimmune disorders
Lack of TRH related to a tumor or disorder of the hypothalamus
What are the replacement hormone products for treating hypothyroidism
Levothyroxine (synthroid) Thyroid Desiccated (Armour Thyroid) prepared from from dried animal thyroid glands and contain both T3 & T4
Indication of thyroid hormone
Replacement therapy in hypothyroidism; pituitary TSH suppression in the treatment of euthyroid gaiters, management of thyroid cancer; thyrotoxicosis in conjunction with other therapy; myxedema coma
Pharmacokinetics of thyroid hormone
Absorbed in GI tract and bound to serum proteins
Elimination is in bile
Does not cross the placenta
Contraindications for thyroid hormone
Known allergy
Thyrotoxicosis (too much thyroid hormone)
Acute MI
Caution when using thyroid hormone
Lactation
Hypoadrenal conditions such as Addison’s
Thyroid hormone exposed to children through lactation can cause growth and development problems
True
Adverse effects of thyroid hormone
Skin reactions
Symptoms of hyperthyroidism
Cardiac stimulation
CNS effects
Drug-Drug interactions with thyroid hormone
Cholestyramine
Oral anticoagulants
Digitalis
Theophylline
Levothyroxine is the prototype for thyroid hormone
True
What causes hyperthyroidism
Graves’ disease
Signs and symptoms of hyperthyroidism
Increased body temperature Flushing
Tachycardia Intolerance to heat
Think skin. Amenorrhea
Palpitations Weight loss
Hypertension Goiter
What are the actions of antithyroid agents
Thioamides prevent the formation of thyroid hormone within the thyroid cells, lowering the serum level of thyroid hormone
Partially inhibits the conversion of T4 to T3
Indications with antithyroid agents
Hyperthyroidism
Pharmacokinetics of antithyroid agents
Well absorbed from GI tract and then concentrated in the thyroid gland
Some excretion can be detected in urine
Contraindications of antithyroid agents
Known allergy
Pregnancy
Cautions with antithyroid agents
Lactation
Adverse effects of antithyroid agents
Thyroid suppression
Drug-drug interactions with antithyroid agents
Oral anticoagulants Theophylline Metoprolol Propranolol Digitalis
Propylthiouracil is the prototype for antithyroid agents
True
Propylthiouracil is used for the treatment of hypothyroidism
True
The thyroid gland uses iodine to produce the thyroid hormones
True
What is hypoparathyroidism
The absence of parathormone
Most likely to occurs with the accidental removal of the parathyroid glands during thyroid surgery
What is hyperparathyroidism
The excessive production of parathormone
Can occurs as a result of parathyroid tumor or certain genetic disorders
What are antihypocalcemic agents
Agents used for stimulation of osteoclasts or bone cells to release calcium from the bone
Increased intestinal absorption of calcium
Increased calcium resorption from the kidneys
Stimulation of cells in the kidney to produce calcitriol
Indications for antihypocalcemic agents
Management of hypocalcemia in patients undergoing chronic renal dialysis
Treatment of hypoparathyroidism
Pharmacokinetics of antihypocalcemic agents
Absorbed from GI tract and widely distributed throughout the body
Stored in liver, fat, muscle, skin, and bones
Metabolized in the liver, excreted in the urine
Contraindications of antihypocalcemic agents
Allergy to vitamin D
Hypercalcemia
Vitamin D toxicity
Pregnancy
Caution with antihypocalcemic agents
History of renal stones
Adverse effects of antihypocalcemic agents
GI effects
CNS effects
Drug-drug interactions with antihypocalcemic agents
Magnesium containing antacids
Cholestyramine or mineral oil
Prototype for antihypocalcemic agents
Calcitriol
Antihypercalcemic agents are used to
Treat PTH excess or hypercalcemia
Act on the serum levels of calcium and do not suppress the parathyroid gland or PTH
What are the antihypercalcemic agents
Bisphosphonates
Calcitonins
Alendronate (fosamax), ibandronate (Boniva), risedronate (actonel) are all bisphosphonates
True
Bisphosphonates should be taken in the AM with a full glass of water, 30 minutes prior to food and drink
Must remain upright for at least 30 minutes after
True
Alendronate is the prototype for antihypercalcemic agents-bisphosphonates
True
What is alendronate used to treat
Osteoporosis
Prototype for antihypercalcemic agents - calcitonins
Calcitonin salmon
