Endocrine Pharmacology Practice Questions

Q: Which of the following medications is relevant in the management of prostatic carcinoma?

Finasteride. ***Finasteride*** - **Finasteride** is a **5α-reductase inhibitor** that blocks the conversion of testosterone to dihydrotestosterone (DHT), which is crucial for prostate growth and development. - It is used in the **chemoprevention of prostatic carcinoma** in high-risk individuals, as demonstrated by the **Prostate Cancer Prevention Trial (PCPT)**, which showed a **25% reduction in prostate cancer risk**. - While finasteride is primarily used for **benign prostatic hyperplasia (BPH)** and **androgenetic alopecia**, its role in reducing prostate cancer risk makes it relevant in prostatic carcinoma management. - It is the only medication among the options with established relevance to prostate cancer. *Danazol* - **Danazol** is an attenuated androgen used primarily for **endometriosis**, **fibrocystic breast disease**, and **hereditary angioedema**. - It suppresses the pituitary-ovarian axis and has **no role in prostatic carcinoma management**. *Clomiphene* - **Clomiphene** is a selective estrogen receptor modulator (SERM) used to induce **ovulation in women** with infertility. - It stimulates gonadotropin release and is **not applicable to prostatic carcinoma** treatment or management. *None of the options* - This is incorrect because **finasteride has an established role** in prostate cancer chemoprevention and is relevant in the broader management of prostatic conditions including carcinoma risk reduction.

Q: Which of the following is the longest acting glucocorticoid?

Dexamethasone. ***Correct: Dexamethasone*** - **Dexamethasone** is a long-acting glucocorticoid with a **biological half-life of 36–72 hours**, making it the longest acting among the options provided - Its prolonged action is due to its **high affinity for the glucocorticoid receptor** and relatively slow metabolism - Provides sustained anti-inflammatory and immunosuppressive effects *Incorrect: Prednisone* - **Prednisone** is an intermediate-acting glucocorticoid with a biological half-life of 12-36 hours - Requires metabolism in the liver to its active form, prednisolone - Duration of action is significantly shorter than dexamethasone *Incorrect: Prednisolone* - **Prednisolone** is the active form of prednisone, with a similar intermediate duration of action (12-36 hours) - Primarily used when liver conversion of prednisone is impaired - Does not possess the extended duration of action characteristic of dexamethasone *Incorrect: Cortisone* - **Cortisone** is a short-acting glucocorticoid with a biological half-life of 8-12 hours - It is a prodrug that needs to be converted to **hydrocortisone** (cortisol) in the liver to become active - Has the shortest duration among all options

Q: Which of the antithyroid drugs inhibits iodine trapping?

Thiocyanates. ***Thiocyanates*** - **Thiocyanates** are competitive inhibitors of the **sodium-iodide symporter (NIS)**, which is responsible for actively transporting iodide into thyroid follicular cells (iodine trapping) [1]. - By blocking NIS, thiocyanates prevent the thyroid gland from accumulating iodide, thereby inhibiting thyroid hormone synthesis [1]. *Radioactive iodine* - **Radioactive iodine (RAI)** primarily works by being taken up by thyroid cells and emitting **beta particles**, which destroy the thyroid tissue [3]. - It does not inhibit iodine trapping, but rather uses the trapping mechanism to concentrate in the thyroid and exert its destructive effect [3]. *Iodides* - **Iodides** (e.g., Lugol's solution) paradoxically inhibit organification and hormone release from the thyroid gland, an effect known as the **Wolff-Chaikoff effect** [2]. - They also decrease the vascularity and size of the thyroid gland, making them useful in preparing patients for thyroidectomy, but do not directly inhibit iodine trapping [2]. *Methimazole* - **Methimazole** is a **thionamide** drug that primarily inhibits the enzyme **thyroid peroxidase**. - This prevents the **organification of iodide** (incorporation of iodine into tyrosine residues) and the **coupling of iodotyrosines** (forming T3 and T4), not the initial trapping of iodine.

Q: What is a potential risk associated with the use of thiazolidinediones in the treatment of type 2 diabetes?

Heart failure. ***Heart failure*** - Thiazolidinediones (TZDs), such as **pioglitazone** and **rosiglitazone**, can cause **fluid retention** and **volume expansion**, which may precipitate or worsen congestive heart failure. - This risk is higher in patients with pre-existing cardiac conditions and is a significant concern for these drugs. *Pulmonary fibrosis* - **Pulmonary fibrosis** is not a known or common adverse effect associated with thiazolidinedione use. - This condition is typically linked to certain other medications (e.g., **amiodarone**, **methotrexate**) or systemic diseases. *Myocarditis* - **Myocarditis**, inflammation of the heart muscle, is not a recognized side effect of thiazolidinediones. - Myocarditis is more commonly caused by viral infections, autoimmune diseases, or hypersensitivity reactions to certain drugs, but not TZDs. *Renal dysfunction* - While TZDs can cause fluid retention, they do not directly cause **renal dysfunction** or damage the kidneys. - In fact, some studies suggest they may have renoprotective effects due to reduced proteinuria, although fluid balance needs careful monitoring in patients with impaired renal function.

Q: Which medication increases insulin secretion from beta cells?

Repaglinide. ***Repaglinide*** - This medication is a **meglitinide analog** that stimulates **insulin release** from pancreatic beta cells by closing ATP-sensitive potassium channels. - Its fast onset and short duration of action make it particularly useful for controlling **postprandial glucose** excursions. *Metformin* - This medication primarily works by **decreasing hepatic glucose production** and improving insulin sensitivity in peripheral tissues. - It does **not directly stimulate insulin secretion** from beta cells; thus, it carries a lower risk of hypoglycemia compared to sulfonylureas or meglitinides. *Pramlintide* - This is an **amylin analog** that works by slowing gastric emptying, suppressing postprandial glucagon secretion, and increasing satiety. - It is an **injectable medication** used as an adjunct to insulin therapy and does not directly enhance insulin secretion from beta cells. *Pioglitazone* - This drug is a **thiazolidinedione** that improves insulin sensitivity in target tissues (e.g., muscle, fat, liver) by activating **peroxisome proliferator-activated receptor-gamma (PPAR-γ)**. - While it improves the body's response to insulin, it does **not directly stimulate insulin secretion** from the beta cells.

Q: Which drug is commonly administered via subdermal implant?

Progestin. ***Progestin*** - **Progestins** (synthetic progestogens like **etonogestrel**) are commonly administered via subdermal implant (e.g., **Nexplanon**, Implanon) for **long-acting reversible contraception (LARC)**. - This method provides a continuous, low dose of hormone, offering effective birth control for **3 years**. - The implant is a small, flexible rod inserted subdermally in the upper arm. *Nicotine* - **Nicotine** is typically administered via **transdermal patches**, gum, inhalers, or nasal sprays for **smoking cessation**, not subdermal implants. - While it's delivered transdermally, the mechanism is through a patch placed on the skin surface, not an implant beneath it. *Fentanyl* - **Fentanyl** is a potent opioid primarily delivered via **transdermal patches** for chronic pain management, or intravenously for acute pain. - It is not administered via a subdermal implant; patches provide continuous release through skin absorption. *GTN* - **Glyceryl trinitrate (GTN)**, or nitroglycerin, is commonly administered as **sublingual tablets** or **transdermal patches** for angina. - It has a very short half-life and is not suitable for a slow-release subdermal implant due to its rapid vasodilatory effects.

Q: Which of the following is not a definite use for Prostaglandin E2 (PGE2)?

Keeps patency of PDA. ***Keeps patency of PDA*** - **Prostaglandin E1 (PGE1)**, not PGE2, is used to maintain the patency of the **ductus arteriosus** in neonates with certain congenital heart defects. - PGE1 causes **vascular smooth muscle relaxation**, preventing closure of the ductus arteriosus. *Contraception* - **PGE2 analogs** are used in various forms of contraception, including emergency contraception and for cervical ripening before elective abortion. - They act by inducing **uterine contractions** and can interfere with implantation or facilitate expulsion of a fertilized egg. *Induces labour* - **PGE2 (dinoprostone)** is commonly used clinically to induce labor by promoting **cervical ripening** and stimulating **uterine contractions**. - It is administered as a vaginal gel or insert to prepare the cervix for delivery. *Therapeutic abortion* - **PGE2 analogs** are used to induce therapeutic abortion, particularly in the second trimester, by causing powerful **uterine contractions** that lead to the expulsion of the fetus. - They are often used in combination with other agents to enhance their efficacy.

Q: Desmopressin is preferred over vasopressin because it:

Is more potent and has little vasoconstrictor activity. **Is more potent and has little vasoconstrictor activity** - **Desmopressin** is a synthetic analog of **vasopressin** (ADH) that is modified to have much higher selectivity for **V2 receptors** in the renal collecting ducts, leading to potent **antidiuretic effects** [1], [3]. - This selective action results in significantly **reduced vasoconstrictor activity** (mediated by V1 receptors) compared to natural vasopressin, making it safer for clinical use to manage water balance without significant cardiovascular side effects [1], [3]. *Is more potent than vasopressin* - While desmopressin is indeed more potent in its **antidiuretic effect** due to increased affinity for **V2 receptors**, this option alone doesn't specify the critical advantage of *reduced vasoconstrictor activity* [3]. - Its superior potency alone doesn't fully explain its preference over vasopressin, as the **side-effect profile** is a major consideration. *Has little vasoconstrictor activity* - This statement is true and highlights a key advantage of desmopressin, but it omits the fact that **desmopressin is also more potent** in its desired antidiuretic effect compared to natural vasopressin [1]. - Both the **potency** and **reduced vasoconstrictor activity** contribute to its superior clinical profile [3]. *Is more selective for V2 receptors than vasopressin* - **Desmopressin's increased selectivity** for **V2 receptors** is the mechanistic basis for its preferred properties, leading to both greater antidiuretic potency and reduced vasoconstriction [1], [4]. - However, the option "Is more potent and has little vasoconstrictor activity" describes the *clinical consequences* of this selectivity, which are the direct reasons for its preferred use [2].

Q: What type of compound is Tibolone?

Synthetic steroidal estrogen. ***Synthetic steroidal estrogen*** - **Tibolone** is a **synthetic steroid** that acts as a selective tissue estrogenic activity regulator (STEAR), mimicking some effects of estrogen, progesterone, and androgens. - Its **steroidal structure** means it is derived from the basic steroid nucleus, setting it apart from non-steroidal compounds. *Natural steroidal estrogen* - **Natural steroidal estrogens** like estradiol are produced endogenously in the body and have a specific chemical structure. - **Tibolone** is a man-made compound developed in a laboratory, not found naturally. *Natural non-steroidal estrogen* - **Natural non-steroidal estrogens** would refer to compounds found in nature (e.g., phytoestrogens) that do not possess a steroid backbone. - **Tibolone** is synthetic and has a **steroidal structure**. *Synthetic non-steroidal estrogen* - **Synthetic non-steroidal estrogens** are man-made compounds (e.g., diethylstilbestrol) that mimic estrogen but lack the steroid nucleus. - **Tibolone**, however, possesses a **steroidal structure**, making this option incorrect.

Q: What is Dinoprost?

Prostaglandin F2α (PGF2α). ***Prostaglandin F2α (PGF2α)*** - **Dinoprost** is the generic name for **Prostaglandin F2α**. - It works by stimulating **myometrial contractions** and promoting cervical ripening, making it useful in obstetrics. *Prostaglandin E2 (PGE2)* - **PGE2** is known as **Dinoprostone** and is also used for cervical ripening and labor induction. - While similar in function, **Dinoprostone** (PGE2) is distinct from **Dinoprost** (PGF2α). *Prostaglandin I2 (PGI2)* - **PGI2** is also known as **Prostacyclin** and acts as a potent **vasodilator** and **inhibitor of platelet aggregation**. - Its primary therapeutic uses are in conditions like **pulmonary hypertension**, which differs from Dinoprost's obstetric uses. *Prostaglandin E1 (PGE1)* - **PGE1** is also known as **Alprostadil** and is used to maintain the **patency of the ductus arteriosus** in neonates with certain congenital heart defects. - It is distinct from Dinoprost and has different clinical applications.

Question 1

Which of the following medications is relevant in the management of prostatic carcinoma?

Accepted Answer

Finasteride

Answer

Clomiphene

Answer

None of the options

Answer

Danazol

Question 2

Which of the following is the longest acting glucocorticoid?

Accepted Answer

Dexamethasone

Answer

Prednisone

Answer

Prednisolone

Answer

Cortisone

Question 3

Which of the antithyroid drugs inhibits iodine trapping?

Accepted Answer

Thiocyanates

Answer

Radioactive iodine

Answer

Iodides

Answer

Methimazole

Question 4

What is a potential risk associated with the use of thiazolidinediones in the treatment of type 2 diabetes?

Accepted Answer

Heart failure

Answer

Pulmonary fibrosis

Answer

Myocarditis

Answer

Renal dysfunction

Question 5

Which medication increases insulin secretion from beta cells?

Accepted Answer

Repaglinide

Answer

Metformin

Answer

Pioglitazone

Answer

Pramlintide

Question 6

Which drug is commonly administered via subdermal implant?

Accepted Answer

Progestin

Answer

Nicotine

Answer

Fentanyl

Answer

GTN

Question 7

Which of the following is not a definite use for Prostaglandin E2 (PGE2)?

Accepted Answer

Keeps patency of PDA

Answer

Induces labour

Answer

Contraception

Answer

Therapeutic abortion

Question 8

Desmopressin is preferred over vasopressin because it:

Accepted Answer

Is more potent and has little vasoconstrictor activity

Answer

Is more potent than vasopressin

Answer

Has little vasoconstrictor activity

Answer

Is more selective for V2 receptors than vasopressin

Question 9

What type of compound is Tibolone?

Accepted Answer

Synthetic steroidal estrogen

Answer

Natural steroidal estrogen

Answer

Natural non-steroidal estrogen

Answer

Synthetic non-steroidal estrogen

Question 10

What is Dinoprost?

Accepted Answer

Prostaglandin F2α (PGF2α)

Answer

Prostaglandin E2 (PGE2)

Answer

Prostaglandin I2 (PGI2)

Answer

Prostaglandin E1 (PGE1)

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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