Endocrine drugs

Question 1

What is the mechanism of action of carbimazole? (1)

Answer 1

Interference with synthesis of thyroid hormones.

Question 2

Name two drugs used for thyrotoxicosis or preparing a patient for thyroidectomy? (2)

Answer 2

Carbimazole and propylthiouracil

Question 3

What is the main side effect associated with treatment with carbimazole? (1)

Answer 3

Agranulocytosis and bone marrow suppression.

Question 4

Why is hydrocortisone and fludrocortisone required for treatment of primary hypoadrenalism but not for hypopituitarism? (2)

Answer 4

Hydrocortisone is glucocorticoid and the mineralocorticoid action is too weak to replace fludrocortisone. However, in hypopituitarism, only hydrocortisone is required as aldosterone is under control of renin-angiotensin system.

Question 5

Why is hydrocortisone unsuitable for long term disease control? (1)

Answer 5

Relatively high mineralocorticoid activity of hydrocortisone causes fluid retention and thus dexamethasone or prednisolone with more predominantly glucocorticoid action are preferred for long term disease suppression.