Thyroid Disorders and Treatments

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Questions and Answers

What is the main effect of Raloxifene in postmenopausal women?

Decreases bone density and increases the risk of fractures.

Increases bone density and decreases urinary calcium excretion.

Improves muscle strength and reduces joint pain.

Increases bone density and decreases vertebral fractures. (correct)

How often should Denosumab be administered for osteoporosis treatment?

Once every 6 months through subcutaneous injection. (correct)

Once every month via oral route.

Once a week intravenously.

Once every year through intramuscular injection.

Which of the following statements is true regarding Calcitonin?

Salmon calcitonin is more potent than recombinant human calcitonin. (correct)

It can be effectively absorbed from the gut.

It primarily promotes osteoclast activity and bone resorption.

It is only available as a nasal spray.

What is the primary function of Strontium ranelate in osteoporosis treatment?

It is laid down on newly formed bone to decrease osteoclastic activity. Signup and view all the answers

What role does Sodium fluoride play in dental health?

It replaces the hydroxyl group in calcium phosphate salts. Signup and view all the answers

What is the primary drug of choice for thyroid hormone replacement therapy in hypothyroidism?

Levothyroxine sodium (T4) Signup and view all the answers

Which of the following antithyroid agents is specifically recommended for use during pregnancy and lactation?

Propylthiouracil (PTU) Signup and view all the answers

What is the half-life of Levothyroxine (T4)?

1 week Signup and view all the answers

Which adverse effect is associated with thioamide drugs like Carbimazole?

Goiter enlargement Signup and view all the answers

What is the effect of excess thyroid hormone in a patient?

Thyrotoxicosis Signup and view all the answers

How is Carbimazole metabolized in the body?

Hydrolyzed into Methimazole Signup and view all the answers

Which surgical procedure is commonly performed for hyperthyroidism?

Total thyroidectomy Signup and view all the answers

What is the primary mechanism of action for thioamide drugs in treating hyperthyroidism?

Block the synthesis of thyroid hormones Signup and view all the answers

What condition results from vitamin D deficiency in children?

Rickets Signup and view all the answers

Which of the following factors does not contribute to osteomalacia in adults?

Sun exposure Signup and view all the answers

Which pharmacologic agent is specifically known to stimulate bone formation by osteoblasts?

Teriparatide Signup and view all the answers

What is the primary role of bisphosphonates in bone disorder management?

Inhibit bone resorption Signup and view all the answers

Which bisphosphonate was the first to be approved for the treatment of osteoporosis?

Alendronate Signup and view all the answers

Which of the following medications is most effective in treating hypercalcemia associated with cancer?

Zoledronic acid Signup and view all the answers

What effect does estrogen have on bone density?

Slows down bone loss Signup and view all the answers

Which of the following is a third-generation bisphosphonate?

Zoledronic acid Signup and view all the answers

What is a primary use of β-Adrenoceptor antagonists like propranolol?

To reduce cardiovascular stimulation associated with hyperthyroidism Signup and view all the answers

What is the duration of maximum effect for iodide salts in treating acute thyrotoxicosis?

10-15 days Signup and view all the answers

What is a contraindication for the use of radioactive iodine (I-131)?

Pregnancy and lactation Signup and view all the answers

What is one of the main characteristics of osteoporosis?

Weakening of bones leading to fractures after minimal trauma Signup and view all the answers

How does radioactive iodine (I-131) affect thyroid tissue?

Destroys thyroid tissue through β-particle emission Signup and view all the answers

What effect does iodide have on thyroid hormone formation?

It inhibits the formation of thyroid hormones Signup and view all the answers

What common deficiency is associated with osteomalacia?

Vitamin D deficiency Signup and view all the answers

What is the half-life of radioactive iodine (I-131)?

8 days Signup and view all the answers

Study Notes

Hypothyroidism

Hyposecretion of thyroid hormone
Treated with thyroid hormone replacement therapy
Two thyroid hormone preparations:
- Levothyroxine sodium (thyroxin, T4)
- Liothyronine sodium (T3)

Hyperthyroidism

Hypersecretion of thyroid hormone
Treated with:
- Antithyroid drugs
- Irradiation
- Surgical removal of the overactive tissue

Levothyroxine and Liothyronine

Levothyroxine is the drug of choice for thyroid hormone replacement in patients with hypothyroidism
Both Levothyroxine and Liothyronine are adequately absorbed following oral administration.
Levothyroxine has a longer half-life than Liothyronine (one week vs two days)
Adverse effects:
- Elderly patients and those with ischemic heart disease may experience angina or myocardial infarction if a high initial dose is given
- Excess thyroid hormone can lead to thyrotoxicosis

Thioamide drugs

Include:
- Carbimazole
- Methimazole
- Propylthiouracil (PTU)
Propylthiouracil is the drug of choice during pregnancy and lactation
Used in patients with Graves' disease to control symptoms before surgery or RAI treatment
Pharmacokinetics:
- Administered orally
- Carbimazole is hydrolyzed into methimazole
Adverse effects:
- Cross the placenta and are secreted in breast milk
- Can cause:
  - Hypothyroidism
  - Goiter enlargement
  - Agranulocytosis (rare)

β-Adrenoceptor Antagonists

Example: Propranolol
Used to reduce cardiovascular stimulation associated with hyperthyroidism
Also used in thyroid storm

Iodide salts

Examples:
- Potassium iodide tablets and solutions
- Saturated solution of potassium iodide
- Lugol solution
Immediate reducing effect on the release of thyroid hormones
Used for short-term therapy:
- Preparing patients for surgery
- Inhibiting the release of thyroid hormone after RAI treatment
Effect:
- Inhibit thyroid hormone formation
- Reduce iodide trapping
- Reduce gland vascularity
Maximum effect occurs after 10-15 days, then diminishes due to loss of inhibitory effect on thyroid.

Radioactive Iodine (RAI)

Colorless and tasteless solution of sodium iodide I-131
Mechanism: absorbed from the gut and concentrated by the thyroid gland, emits β-particles that destroy thyroid tissue
Definitive treatment for:
- Relapsed Graves' disease
- Toxic multinodular goiter
- Toxic solitary nodule
Contraindication: Pregnancy and lactation
Well absorbed orally, given as a single dose.
Half-life: 8 days
Maximum effect takes several weeks, with peak effect around two months.

Bone Disorders

Osteoporosis: gradual reduction in bone mass, leading to fractures after minimal trauma
Osteomalacia: abnormal mineralization of new bone matrix
Rickets: osteomalacia in children
Common causes of osteomalacia:
- Vitamin D deficiency
- Abnormal vitamin D metabolism
- Phosphate deficiency
- Osteoblast dysfunction

Drugs Affecting Calcium and Bone

Bisphosphonates Inhibit bone resorption by osteoclasts
Examples:
- Alendronate
- Pamidronate
- Risedronate
- Tiludronate
- Ibandronate
- Zoledronic acid
Uses:
- Management of Paget disease of bone
- Hypercalcemia
- Osteolytic bone lesions of metastatic cancer
- Reduced risk of developing breast cancer
Effects:
- Inhibit bone resorption
- Reduce tumor burden in bone
- Decrease bone pain
- Reduce risk of fractures in patients with bone metastases.

Estrogen and Raloxifene

Estrogen:
- reduces the formation and activation of osteoclasts, slowing bone loss
Raloxifene:
- Increases bone density in postmenopausal women
- Decreases vertebral fractures in women with osteoporosis

Denosumab

Inactivates gene transcription required for osteoclast survival and function
Administered subcutaneously every 6 months
Used to treat osteoporosis

Calcitonin

Poorly absorbed from the gut, must be administered parenterally or by nasal inhalation
Products:
- Salmon calcitonin
- Recombinant human calcitonin
Salmon calcitonin is 50 to 100 times more potent than human calcitonin
Clinical uses:
- Treats osteoporosis, Paget disease of bone, and hypercalcemia.

Teriparatide

Recombinant form of human PTH
Used to treat osteoporosis

Strontium ranelate

Treatment option for the prevention of osteoporosis
Decreases osteoclastic activity and reduces bone resorption

Fluoride

Sodium fluoride:
- Used to prevent tooth decay and dental caries
- Replaces the hydroxyl group in calcium phosphate salts to form fluorapatite, which is more resistant to erosion

Pharmacological Treatment of Anemia

Iron deficiency anemia (IDA)
Anemia of inflammation and chronic disease (AI/ACD)

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Description

Explore the fundamentals of hypothyroidism and hyperthyroidism, including their paths, treatments, and the role of key medications like Levothyroxine and Liothyronine. Understand the mechanisms of action and possible adverse effects associated with thyroid hormone therapies and antithyroid drugs. Test your knowledge about thyroid function and pharmacotherapy through this quiz.