Endocrine Pharmacology Practice Questions

Q: Which of the following drugs is available as a nasal spray formulation?

Calcitonin. ***Calcitonin*** - **Calcitonin salmon** is available as a nasal spray (Miacalcin®) and is used in the treatment of **postmenopausal osteoporosis**. - Nasal administration provides an alternative to injection for patients who may have difficulty with subcutaneous or intramuscular routes. *Oestrogen* - **Oestrogen** is primarily available in oral, transdermal patch, vaginal cream, or injectable formulations. - While some hormonal therapies are available as nasal sprays (e.g., certain GnRH agonists), **oestrogen itself is not typically administered via this route** for routine indications. *Calcium* - **Calcium** is a mineral supplement predominantly available in oral formulations (e.g., tablets, chewables, liquids). - It is not typically formulated as a nasal spray for systemic absorption or treatment of calcium deficiency. *PTH* - **Teriparatide**, a recombinant form of **parathyroid hormone (PTH)**, is administered via subcutaneous injection. - While it has potent effects on bone, it is not available as a nasal spray due to challenges with absorption and stability.

Q: Tolvaptan is a/an -

Vasopressin antagonist. ***Vasopressin antagonist*** - **Tolvaptan** specifically blocks the action of **vasopressin (antidiuretic hormone)** at the V2 receptor. - This action leads to increased water excretion without affecting electrolyte balance, making it useful in treating conditions like **hyponatremia** and **syndrome of inappropriate antidiuretic hormone secretion (SIADH)**. *ACE inhibitor* - **ACE inhibitors** like captopril or enalapril block the conversion of **angiotensin I to angiotensin II**, reducing vasoconstriction and aldosterone release. - They are primarily used for **hypertension**, **heart failure**, and **diabetic nephropathy**, which is a different mechanism of action than tolvaptan. *Renin inhibitor* - **Renin inhibitors**, such as aliskiren, directly block the **renin enzyme**, preventing the formation of angiotensin I. - This mechanism also targets the **renin-angiotensin-aldosterone system (RAAS)** but at an earlier step than an ACE inhibitor. *Angiotensin antagonist* - **Angiotensin receptor blockers (ARBs)**, such as losartan or valsartan, block the binding of **angiotensin II** to its AT1 receptor. - Similar to ACE inhibitors, they are used for **hypertension** and **heart failure** but do not directly affect vasopressin.

Q: In osteoporosis, bone formation is increased by which drug?

Teriparatide. ***Teriparatide*** - Teriparatide is a recombinant form of **parathyroid hormone (PTH)** that, when administered intermittently, stimulates **osteoblast activity** leading to increased **bone formation**. - It is an **anabolic agent** used in osteoporosis to build new bone rather than just prevent bone loss. *Estrogen* - Estrogen is primarily used to prevent **bone loss** by **inhibiting osteoclast activity** and supporting bone mineralization. - It does not directly **increase bone formation** but rather maintains bone density. *Bisphosphonates* - Bisphosphonates inhibit **osteoclast-mediated bone resorption** by inducing apoptosis in osteoclasts. - They primarily **decrease bone breakdown** and do not directly stimulate new bone formation. *Calcitonin* - Calcitonin is a hormone that **inhibits osteoclast activity** and thus reduces bone resorption. - It is not a bone-forming agent but rather acts to **decrease bone breakdown** and is used for pain relief in vertebral fractures.

Q: Drug not used in SIADH is:

Desmopressin. ***Desmopressin*** - **Desmopressin** is a synthetic analog of **ADH** (antidiuretic hormone), which is **excessive in SIADH**. - Administering desmopressin would worsen SIADH by further increasing water reabsorption and diluting serum sodium. *3% NaCl* - **Hypertonic saline** (like 3% NaCl) is used in SIADH, particularly for severe hyponatremia, to **raise serum sodium levels** rapidly. - It works by increasing the osmotic gradient, drawing water out of cells and into the extracellular space for excretion. *Demeclocycline* - **Demeclocycline** is a **tetracycline antibiotic** that can induce **nephrogenic diabetes insipidus**. - This effect makes the kidneys less responsive to ADH, thus reducing water reabsorption and helping to correct hyponatremia in chronic SIADH. *Tolvaptan* - **Tolvaptan** is an **ADH receptor antagonist** (Aquaretic). - It blocks the action of ADH in the kidneys, leading to increased water excretion without affecting electrolyte excretion, thereby raising serum sodium levels.

Q: Drug of choice for precocious puberty:

GnRH agonists. ***GnRH agonists*** - **GnRH agonists** are the drug of choice for central precocious puberty as they **downregulate GnRH receptors** on the pituitary. - This downregulation leads to a **reduction in gonadotropin release** (LH and FSH), thereby suppressing sex hormone production and halting pubertal progression. *Tamoxifen* - **Tamoxifen** is a **selective estrogen receptor modulator (SERM)** primarily used in **breast cancer treatment**. - While it has **antiestrogenic effects** in breast tissue, it has **estrogenic effects** in other tissues and would not be appropriate for treating precocious puberty as it **does not suppress the central hypothalamic-pituitary-gonadal axis** and may have unpredictable effects on pubertal development. *Cyproterone acetate* - **Cyproterone acetate** is an **antiandrogen** with some progestational effects, mainly used to treat conditions caused by excess androgens, such as hirsutism or severe acne. - While it can suppress some aspects of sexual development by blocking androgen receptors, it **does not directly inhibit the central pubertal cascade** in the same way GnRH agonists do. *Medroxyprogesterone* - **Medroxyprogesterone** is a **progestin** that can suppress gonadotropin release in certain contexts, primarily in managing endometrial hyperplasia or contraception. - It is sometimes used in specific forms of precocious puberty (e.g., peripheral) but is **not the first-line treatment for central precocious puberty** as GnRH agonists are more effective at suppressing the entire hypothalamic-pituitary-gonadal axis.

Q: Hypokalemia is seen in therapy with

Corticosteroids. ***Corticosteroids*** - **Corticosteroids** can cause **hypokalemia** due to their mineralocorticoid activity, which promotes renal potassium excretion. - This effect is often dose-dependent and more pronounced with certain corticosteroids like **fludrocortisone** or high doses of prednisolone. *Diazepam* - **Diazepam** is a **benzodiazepine** that acts on GABA receptors in the brain. - It primarily causes central nervous system effects like sedation and anxiolysis, without directly affecting **potassium levels**. *Ibuprofen* - **Ibuprofen** is a **non-steroidal anti-inflammatory drug (NSAID)**. - It can lead to **renal dysfunction** and **fluid retention**, but it does not directly cause **hypokalemia**. *Digitalis* - **Digitalis** (digoxin) is a cardiac glycoside used to treat **heart failure** and **arrhythmias**. - While **hypokalemia** can exacerbate **digitalis toxicity**, digitalis therapy itself does not significantly cause **hypokalemia**; rather, it's a critical electrolyte to monitor.

Q: Corticosteroid which needs least systemic monitoring is:

Budesonide. ***Budesonide*** - This **corticosteroid** has a very high **first-pass metabolism** in the liver, leading to low systemic bioavailability. - Due to its localized action and minimal systemic exposure, it requires the **least systemic monitoring** compared to other corticosteroids. *Dexamethasone* - Has a **long half-life** and potent **glucocorticoid activity**, leading to significant systemic effects. - Requires careful monitoring for side effects like **hyperglycemia**, osteoporosis, and immune suppression. *Prednisolone* - A commonly used oral corticosteroid with **intermediate systemic potency** and half-life. - Requires monitoring for a range of systemic side effects, including **adrenal suppression** and fluid retention. *Hydrocortisone* - This is a short-acting corticosteroid, and its systemic use can lead to **significant mineralocorticoid effects** in addition to glucocorticoid effects. - Requires monitoring for electrolyte imbalances, **hypertension**, and other systemic corticosteroid side effects.

Q: Anti-inflammatory action of steroids is due to

Inhibition of phospholipase A2. ***Inhibition of phospholipase A2*** - Steroids exert their potent anti-inflammatory effects primarily by inducing the synthesis of **lipocortin-1 (annexin-1)**, which then inhibits **phospholipase A2 (PLA2)** activity. - This inhibition of PLA2 prevents the release of **arachidonic acid** from cell membrane phospholipids, thereby blocking the entire cascade of downstream inflammatory mediators, including prostaglandins, thromboxanes, and leukotrienes. *Inhibition of lipoxygenase* - While leukotrienes (products of the lipoxygenase pathway) are inflammatory mediators, steroids achieve their effect upstream by blocking the precursor (arachidonic acid) rather than directly inhibiting **lipoxygenase**. - **Zileuton** is an example of a drug that directly inhibits lipoxygenase. *Inhibition of cyclooxygenase* - Steroids do not directly inhibit **cyclooxygenase (COX) enzymes**; this is the primary mechanism of action for **NSAIDs (Nonsteroidal Anti-inflammatory Drugs)** like ibuprofen and aspirin. - By inhibiting COX, NSAIDs primarily block the synthesis of prostaglandins and thromboxanes, but not leukotrienes. *Increased activity of lipoprotein lipase* - Increased activity of **lipoprotein lipase (LPL)** by steroids is related to their metabolic effects, such as promoting fat deposition and contributing to steroid-induced dyslipidemia, rather than their anti-inflammatory action. - LPL's role is in the metabolism of triglycerides in lipoproteins, which is distinct from the inflammatory cascade.

Q: Rapid infusion of insulin causes

Hypokalemia. ***Hypokalemia*** - Insulin promotes the uptake of **glucose** and **potassium** into cells, primarily via the Na+/K+-ATPase pump. - Rapid infusion of insulin can cause a rapid shift of potassium from the **extracellular space** into the **intracellular space**, leading to hypokalemia. *Hyponatremia* - While insulin can influence fluid balance, it does not directly cause hyponatremia through a rapid shift of sodium. - **Hyponatremia** is more commonly associated with conditions like excessive fluid intake, heart failure, or SIADH. *Hyperkalemia* - **Hyperkalemia** is the opposite of the effect typically seen with insulin administration; insulin is often used to treat hyperkalemia. - Hyperkalemia can be caused by conditions like **kidney failure**, certain medications (e.g., ACE inhibitors), or **rhabdomyolysis**. *Hypernatremia* - Insulin does not directly cause **hypernatremia**. - **Hypernatremia** is usually a result of **dehydration** or excessive sodium intake, leading to a high concentration of sodium in the blood.

Question 1

Which of the following drugs is available as a nasal spray formulation?

Accepted Answer

Calcitonin

Answer

Oestrogen

Answer

Calcium

Answer

PTH

Question 2

Enuresis persists, and the patient is placed on desmopressin acetate (DDAVP). This medication works by which of the following mechanisms?

Accepted Answer

Increase water permeability and reabsorption in collecting tubules

Answer

Decrease detrusor muscle tone

Answer

Increase external sphincter contraction

Answer

Improves alertness of the patient during the sleep cycle

Question 3

Tolvaptan is a/an -

Accepted Answer

Vasopressin antagonist

Answer

ACE inhibitor

Answer

Renin inhibitor

Answer

Angiotensin antagonist

Question 4

In osteoporosis, bone formation is increased by which drug?

Accepted Answer

Teriparatide

Answer

Estrogen

Answer

Bisphosphonates

Answer

Calcitonin

Question 5

Drug not used in SIADH is:

Accepted Answer

Desmopressin

Answer

3% NaCl

Answer

Demeclocycline

Answer

Tolvaptan

Question 6

Drug of choice for precocious puberty:

Accepted Answer

GnRH agonists

Answer

Tamoxifen

Answer

Cyproterone acetate

Answer

Medroxyprogesterone

Question 7

Hypokalemia is seen in therapy with

Accepted Answer

Corticosteroids

Answer

Diazepam

Answer

Ibuprofen

Answer

Digitalis

Question 8

Corticosteroid which needs least systemic monitoring is:

Accepted Answer

Budesonide

Answer

Dexamethasone

Answer

Prednisolone

Answer

Hydrocortisone

Question 9

Anti-inflammatory action of steroids is due to

Accepted Answer

Inhibition of phospholipase A2

Answer

Inhibition of lipoxygenase

Answer

Inhibition of cyclooxygenase

Answer

Increased activity of lipoprotein lipase

Question 10

Rapid infusion of insulin causes

Accepted Answer

Hypokalemia

Answer

Hyponatremia

Answer

Hyperkalemia

Answer

Hypernatremia

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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