Endocrine Pharmacology Practice Questions

Q: If a diabetic patient being treated with an oral hypoglycemic agent develops dilutional hyponatremia, which one of the following could be responsible for this effect?

Chlorpropamide. ***Chlorpropamide*** - **Chlorpropamide**, a first-generation sulfonylurea, has been associated with inducing **dilutional hyponatremia** due to its effect on enhancing **antidiuretic hormone (ADH)** secretion or action. - This effect is more pronounced in older patients and those with underlying cardiac or renal disease. *Tolbutamide* - **Tolbutamide** is a first-generation sulfonylurea but is less commonly associated with significant **hyponatremia** compared to chlorpropamide. - While all sulfonylureas can, to varying degrees, affect water balance, its potency in causing **ADH-like effects** is lower. *Glimepiride* - **Glimepiride** is a second-generation sulfonylurea, which generally has a lower risk of causing **hyponatremia** compared to first-generation drugs like chlorpropamide. - Second-generation sulfonylureas are known for their improved safety profile regarding water and electrolyte balance. *Glyburide* - **Glyburide** (also known as glibenclamide) is another second-generation sulfonylurea with a lower incidence of **hyponatremia** than chlorpropamide. - Its metabolic profile results in less marked effects on **ADH** release or potentiation.

Q: Which of the following medications is not associated with causing hyperprolactinemia?

Lasix. ***Lasix*** - **Furosemide (Lasix)** is a loop diuretic primarily used to treat **edema** and **hypertension**. It acts on the kidneys to increase urine output and is not known to directly affect prolactin secretion pathways. - Its mechanism of action involves inhibiting the Na-K-2Cl cotransporter in the thick ascending limb of the loop of Henle, a process unrelated to dopamine or prolactin regulation. *Metoclopramide* - **Metoclopramide** is a **dopamine D2 receptor antagonist** that can readily cross the blood-brain barrier, leading to increased prolactin secretion by blocking the inhibitory effect of dopamine on prolactin release from the pituitary gland. - It is often used as an **antiemetic** and **prokinetic agent**, and hyperprolactinemia is a common side effect. *Haloperidol* - **Haloperidol** is a potent **first-generation antipsychotic** that significantly blocks **dopamine D2 receptors** in the central nervous system. - This blockade directly inhibits the dopamine-mediated suppression of prolactin, leading to a dose-dependent increase in serum prolactin levels. *Trifluoperazine* - **Trifluoperazine** is another **first-generation antipsychotic** that also acts as a potent **dopamine D2 receptor antagonist**. - Its strong dopamine D2 receptor blockade frequently results in **hyperprolactinemia**, a common side effect of typical antipsychotics.

Q: Which of the following is the drug of choice for the syndrome of inappropriate secretion of antidiuretic hormone (SIADH)?

Demeclocycline. ***Demeclocycline*** - **Demeclocycline** is a **tetracycline antibiotic** that induces **nephrogenic diabetes insipidus**, making the renal tubules less responsive to ADH. - This effect helps in treating SIADH by promoting water excretion and correcting **hyponatremia**. *Vasopressin* - **Vasopressin** (ADH) is the hormone that is excessively secreted in SIADH, leading to water retention. - Administering vasopressin would **aggravate** SIADH symptoms by increasing water reabsorption. *Thiazide diuretic* - **Thiazide diuretics** can worsen hyponatremia in SIADH by causing **sodium loss** and **reducing free water clearance**. - Volume depletion from thiazides can paradoxically enhance ADH activity, making them contraindicated in SIADH. *Chlorpropamide* - **Chlorpropamide** is a **sulfonylurea** that can actually **potentiate ADH action**, thereby worsening SIADH. - It works by increasing the sensitivity of renal tubules to vasopressin, which is counterproductive in SIADH management.

Q: Precocious puberty is treated by administering

LHRH analogs (e.g., Leuprolide). ***LHRH analogs (e.g., Leuprolide)*** - **LHRH analogs** (GnRH agonists) are the standard treatment for central precocious puberty through continuous, non-pulsatile stimulation of the pituitary. - This leads to **downregulation and desensitization** of GnRH receptors, effectively suppressing gonadotropin (LH and FSH) release. - Suppression halts progression of pubertal development, preventing further development of **secondary sexual characteristics** and preserving final adult height potential. *Oestrogen* - Administering **oestrogen** would worsen precocious puberty by accelerating the development of secondary sexual characteristics and advancing bone age. - Oestrogen is a primary hormone responsible for female pubertal changes, so exogenous administration would **exacerbate** the condition. *Gonadotropin-Releasing Hormone (GnRH)* - Native **GnRH** is not used for treatment because it requires **pulsatile administration** to maintain normal function, which would stimulate (not suppress) gonadotropin release. - Without the continuous receptor exposure that causes downregulation, native GnRH would promote rather than suppress pubertal progression. - Treatment requires **GnRH agonists (LHRH analogs)** that provide sustained receptor stimulation leading to desensitization. *Testosterone* - Administering **testosterone** would accelerate precocious puberty, especially in males, leading to early development of male secondary sexual characteristics. - Testosterone would advance bone age prematurely, potentially compromising the child's **final adult height**.

Q: Which of the following medications does not cause hirsutism?

Flutamide. ***Flutamide*** - **Flutamide** is an **anti-androgen** that blocks androgen receptors, thereby *reducing* the effects of androgens and preventing hirsutism. - It is used in conditions like prostate cancer to counteract androgenic effects and would not cause increased hair growth. *Norethisterone* - **Norethisterone** is a synthetic progestin that can have **androgenic effects** in some individuals. - These androgenic properties can lead to side effects like **hirsutism**, acne, and oily skin. *Danazol* - **Danazol** is a synthetic androgen that has **pronounced androgenic activity**. - Its androgenic effects are well-known to cause side effects such as **hirsutism**, acne, and deepening of the voice. *Phenytoin* - **Phenytoin** is an anticonvulsant medication that can induce **hirsutism** as a common side effect. - The mechanism is not fully understood but may involve stimulating hair follicle growth.

Q: Which of the following statements is true about atosiban?

is an oxytocin receptor antagonist. ***is an oxytocin receptor antagonist*** - **Atosiban** works by competitively binding to **oxytocin receptors** in the myometrium, thereby preventing oxytocin from stimulating uterine contractions. - This action makes it effective in delaying **preterm labor** by reducing the frequency and intensity of contractions. - Atosiban is classified as a **tocolytic drug** specifically because of its oxytocin receptor antagonism. *is least effective in inhibiting preterm uterine contractions* - **Atosiban** is an **effective tocolytic** used to delay preterm labor, making this statement incorrect. - Studies show it can prolong pregnancy for several days, allowing for the administration of **corticosteroids** for fetal lung maturation. *is a progesterone receptor antagonist* - **Atosiban** specifically targets **oxytocin receptors**, not progesterone receptors. - Progesterone receptor antagonists (e.g., **mifepristone**) would induce labor rather than suppress it. *acts primarily on beta-adrenergic receptors* - **Atosiban** does not act on beta-adrenergic receptors; it is an **oxytocin receptor antagonist**. - Beta-adrenergic agonists like **ritodrine** and **terbutaline** are different tocolytics that work by relaxing uterine smooth muscle through beta-2 receptor stimulation.

Q: What is the primary condition for which calcitriol is used as a treatment?

Secondary hyperparathyroidism. Secondary hyperparathyroidism - Calcitriol is the active form of vitamin D (1,25-dihydroxyvitamin D₃), and it is crucial for regulating calcium and phosphate levels in the body [1]. - In secondary hyperparathyroidism, often seen in chronic kidney disease (CKD), the kidneys cannot convert vitamin D to its active form, leading to hypocalcemia and increased PTH secretion [1], [2]. - Calcitriol supplementation helps to increase calcium absorption from the gut and suppress the release of parathyroid hormone (PTH), thereby treating the underlying cause of secondary hyperparathyroidism [1], [2]. - This is the primary therapeutic indication for calcitriol in clinical practice. Lichen planus - This is a chronic inflammatory condition affecting the skin, hair, nails, and mucous membranes - Typically treated with corticosteroids or other immunosuppressants - Calcitriol has no primary role in the treatment of lichen planus; its therapeutic applications are predominantly related to calcium and bone metabolism Pemphigus - Pemphigus is a group of rare autoimmune blistering diseases that affect the skin and mucous membranes - Primary treatment involves immunosuppressants like corticosteroids, often in high doses - Calcitriol is not indicated for the treatment of pemphigus, as its mechanism of action is unrelated to the autoimmune processes characteristic of this disease Leprosy - Leprosy is a chronic infectious disease caused by the bacterium Mycobacterium leprae - Treated with multi-drug therapy (MDT), which includes antibiotics like rifampicin, dapsone, and clofazimine - Calcitriol is not an antibiotic and therefore has no role in treating the bacterial infection responsible for leprosy

Q: Which of the following is preferred for infertility treatment of a female with increased prolactin levels?

Cabergoline. ***Cabergoline*** - **Cabergoline** is a **dopamine agonist** that is highly effective in normalizing prolactin levels and restoring fertility in women with hyperprolactinemia. - It has a **longer half-life** and is generally associated with **fewer side effects** compared to other dopamine agonists, allowing for less frequent dosing (once or twice weekly). *Dopamine* - While **dopamine** itself is the natural inhibitor of prolactin secretion, it has a **very short half-life** and cannot be administered orally as a long-term treatment. - It is typically used as an IV pressor agent in critical care and is not suitable for treating chronic hyperprolactinemia. *Carbidopa* - **Carbidopa** is a **decarboxylase inhibitor** used to prevent the peripheral metabolism of levodopa, allowing more levodopa to reach the brain. - It is primarily used in the treatment of **Parkinson's disease** and has no direct role in lowering prolactin levels. *Bromocriptine* - **Bromocriptine** is also a **dopamine agonist** used to treat hyperprolactinemia, but it typically requires **daily dosing** and is associated with a higher incidence of side effects like nausea and dizziness. - While effective, **cabergoline** is generally preferred due to its better tolerability and convenience.

Q: In thyrotoxicosis, which of the following symptoms is least effectively controlled by beta-blockers?

Oxygen consumption. ***Oxygen consumption*** - Beta-blockers primarily address the **adrenergic manifestations** of thyrotoxicosis, but they do not directly inhibit the increased **metabolic rate** or **thyroid hormone production** that drives higher oxygen consumption. - The elevated oxygen consumption in thyrotoxicosis is a direct result of enhanced cellular metabolism due to excess thyroid hormones, which beta-blockers do not counteract. *Tremors* - **Thyrotoxic tremors** are significantly mediated by **beta-adrenergic stimulation**, making them highly responsive to beta-blocker therapy. - Blocking beta-receptors reduces the sympathetic drive that contributes to these fine muscle tremors. *Tachycardia* - **Tachycardia** in thyrotoxicosis is a classic symptom of **increased sympathetic activity**, which beta-blockers effectively block. - Beta-blockers reduce heart rate by inhibiting beta-1 receptors in the myocardium, thereby relieving palpitations and rapid heart rate. *Anxiety* - **Anxiety** is often secondary to the **adrenergic overactivity** and overall heightened metabolic state associated with thyrotoxicosis. - By dampening the sympathetic nervous system, beta-blockers can alleviate anxiety and nervousness.

Q: Among currently prescribed medications for diabetes mellitus, deaths from lactic acidosis are most commonly associated with which one of the following?

Metformin. ***Metformin*** - While generally safe, **lactic acidosis** is a rare but serious complication of metformin, particularly in patients with **renal impairment**, congestive heart failure, or other conditions predisposing to acidosis [1]. - Metformin inhibits **hepatic gluconeogenesis** and increases anaerobic glycolysis, which can lead to lactate accumulation if clearance is compromised [1]. *Tolbutamide* - Tolbutamide is an older **sulfonylurea** medication. - Its primary adverse effect is **hypoglycemia**, not lactic acidosis. *Phenformin* - **Phenformin** is a biguanide like metformin but was withdrawn from most markets due to a significantly higher risk of **lactic acidosis** [2]. - Although it caused frequent deaths from lactic acidosis, it is **no longer a currently prescribed medication** in most countries, making metformin the current agent most commonly associated with this risk. *Glipizide* - Glipizide is a **sulfonylurea** medication. - Its main side effect is **hypoglycemia**, and it does not directly cause lactic acidosis.

Question 1

If a diabetic patient being treated with an oral hypoglycemic agent develops dilutional hyponatremia, which one of the following could be responsible for this effect?

Accepted Answer

Chlorpropamide

Answer

Tolbutamide

Answer

Glimepiride

Answer

Glyburide

Question 2

Which of the following medications is not associated with causing hyperprolactinemia?

Accepted Answer

Lasix

Answer

Haloperidol

Answer

Trifluoperazine

Answer

Metoclopramide

Question 3

Which of the following is the drug of choice for the syndrome of inappropriate secretion of antidiuretic hormone (SIADH)?

Accepted Answer

Demeclocycline

Answer

Vasopressin

Answer

Thiazide diuretic

Answer

Chlorpropamide

Question 4

Precocious puberty is treated by administering

Accepted Answer

LHRH analogs (e.g., Leuprolide)

Answer

Oestrogen

Answer

Gonadotropin-Releasing Hormone (GnRH)

Answer

Testosterone

Question 5

Which of the following medications does not cause hirsutism?

Accepted Answer

Flutamide

Answer

Danazol

Answer

Phenytoin

Answer

Norethisterone

Question 6

Which of the following statements is true about atosiban?

Accepted Answer

is an oxytocin receptor antagonist

Answer

is least effective in inhibiting preterm uterine contractions

Answer

is a progesterone receptor antagonist

Answer

acts primarily on beta-adrenergic receptors

Question 7

What is the primary condition for which calcitriol is used as a treatment?

Accepted Answer

Secondary hyperparathyroidism

Answer

Pemphigus

Answer

Lichen planus

Answer

Leprosy

Question 8

Which of the following is preferred for infertility treatment of a female with increased prolactin levels?

Accepted Answer

Cabergoline

Answer

Dopamine

Answer

Carbidopa

Answer

Bromocriptine

Question 9

In thyrotoxicosis, which of the following symptoms is least effectively controlled by beta-blockers?

Accepted Answer

Oxygen consumption

Answer

Tremors

Answer

Tachycardia

Answer

Anxiety

Question 10

Among currently prescribed medications for diabetes mellitus, deaths from lactic acidosis are most commonly associated with which one of the following?

Accepted Answer

Metformin

Answer

Tolbutamide

Answer

Glipizide

Answer

Phenformin

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

On this page

Practice by Chapter

Want unlimited practice?