Endocrine Pharmacology Practice Questions

Q: Bone resorption is decreased by all of the following agents except:

Teriparatide. **Explanation:** The core concept of this question lies in distinguishing between **antiresorptive agents** (which decrease bone resorption) and **anabolic agents** (which increase bone formation). **Why Teriparatide is the correct answer:** Teriparatide is a recombinant form of human **Parathyroid Hormone (PTH)**. When administered in an **intermittent, low-dose pulsatile fashion**, it acts as a potent **anabolic agent**. It stimulates osteoblast activity and increases bone formation more than bone resorption, leading to a net increase in Bone Mineral Density (BMD). Unlike the other options, its primary therapeutic goal is not to decrease resorption, but to build new bone. **Analysis of Incorrect Options:** * **Strontium Ranelate:** This is a "dual-action" agent. It uniquely **decreases bone resorption** (by inhibiting osteoclast differentiation) while simultaneously increasing bone formation. * **Alendronate:** A classic **Bisphosphonate**. It is a potent antiresorptive agent that induces osteoclast apoptosis, thereby directly decreasing bone resorption. * **Raloxifene:** A **Selective Estrogen Receptor Modulator (SERM)**. It mimics estrogen's effect on bone, inhibiting osteoclast activity and decreasing bone resorption. **NEET-PG High-Yield Pearls:** * **Teriparatide Side Effects:** Hypercalcemia, hyperuricemia, and a theoretical risk of Osteosarcoma (avoid in Paget’s disease or prior radiation). * **Denosumab:** Another high-yield antiresorptive; it is a monoclonal antibody against **RANKL**. * **Bisphosphonates:** The drug of choice for Osteoporosis; known for side effects like esophagitis and Osteonecrosis of the Jaw (ONJ). * **PTH Paradox:** Continuous high levels of PTH (as in Hyperparathyroidism) cause bone resorption, but intermittent low doses (Teriparatide) cause bone formation.

Q: All of the following drugs used in the management of diabetes mellitus cause hypoglycemia except?

Metformin. The correct answer is Metformin (Option A). The fundamental distinction in diabetes pharmacology lies between Euglycemics (drugs that lower high blood glucose without causing hypoglycemia) and Hypoglycemics (drugs that actively stimulate insulin secretion). 1. Why Metformin is the correct answer: Metformin belongs to the Biguanide class. Its primary mechanism of action is the activation of AMP-activated protein kinase (AMPK), which leads to decreased hepatic gluconeogenesis and improved peripheral insulin sensitivity. Because Metformin does not stimulate the pancreas to release insulin, it does not cause hypoglycemia when used as monotherapy. It is therefore classified as a "euglycemic" agent. 2. Why the other options are incorrect: * Tolbutamide (Option B), Glibenclamide (Option C), and Glipizide (Option D) are all Sulfonylureas [1], [2]. * Mechanism: They act by closing the ATP-sensitive K⁺ channels in the pancreatic beta-cell membrane [3]. This causes depolarization, leading to calcium influx and the forced release of pre-formed insulin [3]. * Since insulin secretion is stimulated regardless of the ambient blood glucose levels, these drugs carry a significant risk of hypoglycemia [1], [3]. High-Yield Clinical Pearls for NEET-PG: * Drug of Choice: Metformin is the first-line drug for Type 2 Diabetes Mellitus (T2DM). * Weight Neutrality: Unlike Sulfonylureas and Insulin (which cause weight gain), Metformin is weight-neutral or promotes modest weight loss. * Lactic Acidosis: The most serious (though rare) side effect of Metformin is lactic acidosis; it is contraindicated in patients with significant renal impairment (eGFR <30 mL/min). * Other Euglycemics: Apart from Biguanides, other classes that typically do not cause hypoglycemia as monotherapy include Thiazolidinediones (Pioglitazone), DPP-4 inhibitors (Gliptins), and SGLT-2 inhibitors (Gliflozins).

Q: Which of the following is a selective progesterone receptor modulator?

Ulipristal. **Explanation:** **Ulipristal acetate** is the correct answer because it is a **Selective Progesterone Receptor Modulator (SPRM)**. SPRMs are ligands that exert tissue-specific progestational or anti-progestational effects by binding to progesterone receptors. Ulipristal acts primarily as a partial agonist/antagonist. Its clinical utility stems from its ability to inhibit ovulation (used as **emergency contraception** within 120 hours) and to reduce the size of **uterine fibroids** by inhibiting cell proliferation and inducing apoptosis. **Analysis of Incorrect Options:** * **Tamoxifen (A) and Toremifene (D):** These are **SERMs** (Selective Estrogen Receptor Modulators). They act as estrogen antagonists in the breast but agonists in the bone and endometrium (Tamoxifen). They are primarily used in the management of hormone-responsive breast cancer. * **Nomegestrol (C):** This is a **pure progestin** (19-norprogesterone derivative). It is used in combined oral contraceptive pills and hormone replacement therapy, but it does not possess the modulator (mixed agonist/antagonist) properties characteristic of SPRMs. **High-Yield Facts for NEET-PG:** * **Mifepristone:** Another key SPRM (often classified as an anti-progestin). It is used for medical abortion (combined with Misoprostol) and Cushing’s syndrome. * **Emergency Contraception:** Ulipristal (30 mg) is effective up to **5 days (120 hours)** after unprotected intercourse, whereas Levonorgestrel is ideally used within 72 hours. * **Fibroid Management:** Ulipristal is unique for its non-surgical management of leiomyomas, though liver function monitoring is required due to rare reports of hepatotoxicity.

Q: A 38-year-old male with known type 2 diabetes mellitus, treated with oral hypoglycemic drugs, presents with complaints of excessive thirst, increased urinary frequency, and a burning sensation during urination. Which of the following medications could be the cause of these symptoms?

Dapagliflozin. **Explanation:** The patient is presenting with symptoms of **polyuria, polydipsia, and a Urinary Tract Infection (UTI)**, characterized by the burning sensation during urination. Among the given options, **Dapagliflozin** is the most likely cause. **1. Why Dapagliflozin is correct:** Dapagliflozin is an **SGLT-2 inhibitor** (Sodium-Glucose Co-transporter 2 inhibitor). It works by inhibiting glucose reabsorption in the proximal convoluted tubule of the kidney, leading to **therapeutic glucosuria** [2]. * **Polyuria/Polydipsia:** The presence of glucose in the urine causes osmotic diuresis, leading to increased urinary frequency and compensatory thirst [1]. * **UTI/Candidiasis:** High glucose concentration in the urinary tract provides a fertile medium for bacterial and fungal growth, significantly increasing the risk of UTIs and vulvovaginal candidiasis. **2. Why other options are incorrect:** * **Exenatide (GLP-1 agonist):** Primarily causes gastrointestinal side effects like nausea, vomiting, and a risk of pancreatitis. It does not cause glucosuria. * **Glipizide (Sulfonylurea):** Its main side effects are hypoglycemia and weight gain [3]. It does not increase the risk of UTIs. * **Metformin (Biguanide):** Most common side effects are GI-related (diarrhea, abdominal bloating) and, rarely, lactic acidosis. It does not cause osmotic diuresis. **High-Yield Clinical Pearls for NEET-PG:** * **SGLT-2 Inhibitors ("-gliflozins"):** Associated with **Euglycemic Diabetic Ketoacidosis (eDKA)** and Fourner’s gangrene. * **Cardiorenal Benefits:** They are now first-line for patients with Heart Failure (HFrEF) and Chronic Kidney Disease (CKD), regardless of diabetes status. * **Contraindication:** Avoid if eGFR is significantly low (usually <30 mL/min/1.73m²) [2].

Q: Bisphosphonates are not indicated in which of the following conditions?

Vitamin D intoxication. **Explanation:** **Bisphosphonates** (e.g., Alendronate, Zoledronate) are structural analogs of pyrophosphate that primarily act by inhibiting **osteoclast-mediated bone resorption**. **Why Vitamin D Intoxication is the Correct Answer:** Vitamin D intoxication causes hypercalcemia primarily through **increased intestinal absorption of calcium** and increased renal reabsorption, rather than excessive bone resorption. The primary treatment for Vitamin D toxicity involves stopping Vitamin D intake, low calcium diet, hydration, and the use of **Glucocorticoids** (which antagonize Vitamin D action by decreasing intestinal calcium absorption). Bisphosphonates are ineffective here because the source of excess calcium is dietary/intestinal, not the bone matrix. **Analysis of Other Options:** * **Hypercalcemia:** Bisphosphonates (especially IV Zoledronate and Pamidronate) are the drugs of choice for **Hypercalcemia of Malignancy**, as they prevent the release of calcium from the bone. * **Osteoporosis:** They are first-line agents for postmenopausal and steroid-induced osteoporosis. They increase Bone Mineral Density (BMD) by inhibiting osteoclastic activity. * **Cancer-induced osteolysis:** In conditions like Multiple Myeloma or bony metastases, bisphosphonates reduce skeletal-related events (SREs) and bone pain by stopping tumor-induced bone destruction. **High-Yield NEET-PG Pearls:** * **Mechanism:** They bind to hydroxyapatite crystals and inhibit the enzyme **farnesyl pyrophosphate (FPP) synthase** in the mevalonate pathway of osteoclasts. * **Administration:** Oral bisphosphonates must be taken on an empty stomach with a full glass of water, and the patient must remain upright for 30 minutes to prevent **erosive esophagitis**. * **Adverse Effects:** Osteonecrosis of the Jaw (ONJ) and atypical subtrochanteric fractures (with long-term use).

Q: Peripheral conversion of thyroxine (T4) to triiodothyronine (T3) is inhibited by which of the following medications?

Propranolol. **Explanation:** The peripheral conversion of **T4 (Thyroxine)** to the more potent **T3 (Triiodothyronine)** is mediated by the enzyme **5'-deiodinase**. Inhibiting this enzyme is a crucial therapeutic strategy in managing severe hyperthyroidism and thyroid storm, as it rapidly lowers the levels of active thyroid hormone. **1. Why Propranolol is correct:** Propranolol is a non-selective beta-blocker. Beyond its ability to antagonize the cardiovascular effects of thyrotoxicosis (tachycardia, palpitations), high doses of propranolol uniquely inhibit the **5'-deiodinase enzyme**. This dual action—symptomatic control and reduction of active T3 levels—makes it the preferred beta-blocker in thyroid emergencies. **2. Why the other options are incorrect:** * **Diltiazem:** A calcium channel blocker used for rate control in hyperthyroid patients who cannot tolerate beta-blockers. However, it has **no effect** on the peripheral conversion of T4 to T3. * **Sotalol:** While it is a beta-blocker, it lacks the specific inhibitory effect on 5'-deiodinase seen with propranolol. * **Sodium Iodide:** It acts via the **Wolff-Chaikoff effect** to acutely inhibit the *release* of thyroid hormones from the gland and decrease its vascularity. It does not inhibit peripheral conversion. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for 5'-deiodinase inhibitors:** "**P**-**P**-**P**-**S**" (**P**ropranolol, **P**ropylthiouracil (PTU), **P**rednisolone/Glucocorticoids, and **S**odium Ipodate/Amiodarone). * **Drug of Choice (DOC):** Propranolol is the DOC for symptomatic relief in thyrotoxicosis. * **PTU vs. Methimazole:** PTU is preferred in thyroid storm specifically because it inhibits peripheral conversion, whereas Methimazole does not.

Q: What is the characteristic problem in females taking nor-ethisterone?

Irregular bleeding. **Explanation:** **Norethisterone** (Norethindrone) is a first-generation synthetic progestin derived from 19-nortestosterone. It is commonly used in oral contraceptive pills (OCPs), hormone replacement therapy, and for the management of endometriosis or dysfunctional uterine bleeding. **1. Why Irregular Bleeding is Correct:** The most characteristic side effect of progestin-only preparations (like the "mini-pill" or high-dose norethisterone) is **irregular breakthrough bleeding** or spotting. This occurs because progestins alone cause the endometrial lining to become thin, atrophic, and vascularly fragile. Unlike combined pills, there is no estrogen to stabilize the endometrium, leading to unpredictable shedding. **2. Analysis of Incorrect Options:** * **Thromboembolism:** This is primarily a risk associated with the **estrogen** component of OCPs (which increases clotting factors) or third-generation progestins (like desogestrel). Norethisterone has a negligible risk of thromboembolism. * **Hirsutism:** While norethisterone has slight androgenic activity, it is more likely to cause acne or oily skin rather than frank hirsutism. In clinical practice, irregular bleeding is a far more frequent and "characteristic" complaint. * **Weight gain:** Though often reported by patients, clinical studies show a weak correlation with low-dose progestins compared to the significant incidence of menstrual irregularities. **Clinical Pearls for NEET-PG:** * **Norethisterone** is a "19-nortestosterone" derivative; these are known for being more androgenic than "pregnane" derivatives (like Medroxyprogesterone). * **High-yield use:** It is frequently used to **delay menses** (started 3 days before the expected period). * **Contraindication:** Undiagnosed vaginal bleeding is a primary contraindication for its use.

Q: Denosumab, a monoclonal antibody against RANK ligand, is used for the treatment of which condition?

Osteoporosis. **Explanation:** **Denosumab** is a fully human monoclonal antibody that targets and binds to **RANK ligand (RANKL)**. In the bone remodeling cycle, osteoblasts produce RANKL, which binds to RANK receptors on osteoclast precursors. This interaction is essential for the formation, function, and survival of osteoclasts (the cells responsible for bone resorption). By inhibiting RANKL, Denosumab prevents osteoclast activation, thereby increasing bone mineral density and reducing fracture risk. It is primarily indicated for **postmenopausal osteoporosis** and bone loss in patients undergoing hormone ablation therapy for cancer. **Analysis of Incorrect Options:** * **A & D (Rheumatoid Arthritis & SLE):** These are systemic autoimmune inflammatory disorders. While chronic inflammation and steroid use in these conditions can lead to secondary osteoporosis, Denosumab is not a primary treatment for the underlying autoimmune pathology. Drugs like TNF-inhibitors or DMARDs are used here. * **C (Osteoarthritis):** This is a degenerative joint disease involving cartilage wear and tear, not a primary disorder of systemic bone resorption. Denosumab has no role in its management. **High-Yield Clinical Pearls for NEET-PG:** * **Dosage:** For osteoporosis, it is administered as a **60 mg subcutaneous injection once every 6 months**. * **Giant Cell Tumor of Bone:** Denosumab is also the drug of choice for this condition (at higher doses), as these tumors are rich in RANKL-expressing osteoclast-like giant cells. * **Adverse Effects:** The most significant side effects include **hypocalcemia** (must check calcium levels before administration) and **Osteonecrosis of the Jaw (ONJ)**. * **Comparison:** Unlike bisphosphonates, Denosumab can be used in patients with **renal impairment**, as it is not cleared by the kidneys.

Q: GnRH agonist is used in all of the following EXCEPT?

Hypoestrogenism. The correct answer is **C. Hypoestrogenism**. **Mechanism of Action:** GnRH agonists (e.g., Leuprolide, Goserelin, Nafarelin) act on the pituitary gland. While an acute dose causes a "flare" of gonadotropins, **continuous/chronic administration** leads to the downregulation and desensitization of GnRH receptors [2]. This results in a state of **hypogonadotropic hypogonadism**, effectively lowering levels of estrogen and testosterone [2]. Therefore, GnRH agonists **cause** hypoestrogenism rather than treat it. **Analysis of Options:** * **A. Precocious Puberty:** Continuous GnRH agonists suppress the premature activation of the hypothalamic-pituitary-gonadal axis, delaying the onset of puberty and preventing premature epiphyseal closure [2]. * **B. Endometriosis:** These drugs create a "pseudomenopausal" state. By inducing hypoestrogenism, they cause the ectopic endometrial tissue to atrophy, providing symptomatic relief [1]. * **D. Congenital Adrenal Hyperplasia (CAH):** While not first-line, GnRH agonists are used as an adjunct in children with CAH who develop **secondary (central) precocious puberty** due to advanced bone age and early maturation of the axis. **Clinical Pearls for NEET-PG:** * **Pulsatile administration** of GnRH is used to treat **infertility** (stimulates FSH/LH) [2]. * **Continuous administration** is used for "medical castration" in **Prostate Cancer**, Endometriosis, and Uterine Fibroids [1]. * **Side Effects:** Hot flashes, decreased bone mineral density (osteoporosis), and vaginal dryness (all due to the induced hypoestrogenic state). * **Add-back therapy:** Low-dose estrogen/progestin is often given alongside GnRH agonists in endometriosis to prevent bone loss without losing the therapeutic effect.

Q: Galactorrhea may be associated with the use of all the following drugs except?

Pyridoxine. ### Explanation The physiological regulation of prolactin is primarily under the **inhibitory control of Dopamine** (Prolactin Inhibitory Factor) via D2 receptors in the anterior pituitary. Any drug that decreases dopamine levels or blocks its receptors will lead to hyperprolactinemia, resulting in **galactorrhea**. **Why Pyridoxine is the correct answer:** **Pyridoxine (Vitamin B6)** acts as a cofactor for the enzyme *L-amino acid decarboxylase*, which converts L-Dopa to Dopamine. By increasing peripheral dopamine synthesis, pyridoxine actually **suppresses prolactin secretion**. Historically, high doses of pyridoxine were used to treat lactation; therefore, it prevents rather than causes galactorrhea. **Analysis of Incorrect Options:** * **Methyldopa (Option A):** It is a centrally acting antihypertensive that acts as a "false neurotransmitter." It decreases central dopamine levels, leading to increased prolactin release. * **Tricyclic Antidepressants (Option B):** TCAs (like Amitriptyline) can cause galactorrhea by inhibiting dopamine activity or through mild serotonergic stimulation of prolactin. * **Phenothiazines (Option D):** These are typical antipsychotics (e.g., Chlorpromazine) that act as potent **D2 receptor antagonists** in the tuberoinfundibular pathway, making them a very common cause of drug-induced galactorrhea. **High-Yield Clinical Pearls for NEET-PG:** 1. **Metoclopramide and Domperidone** (anti-emetics) are frequent culprits of galactorrhea due to D2 blockade. 2. **Reserpine** causes galactorrhea by depleting dopamine stores. 3. **Bromocriptine and Cabergoline** (Dopamine agonists) are the drugs of choice for treating hyperprolactinemia/prolactinomas. 4. **Pyridoxine Interaction:** It reduces the efficacy of Levodopa in Parkinson’s disease by increasing its peripheral metabolism (unless a DOPA-decarboxylase inhibitor like Carbidopa is added).

Question 1

Bone resorption is decreased by all of the following agents except:

Accepted Answer

Teriparatide

Answer

Strontium ranelate

Answer

Alendronate

Answer

Raloxifene

Question 2

All of the following drugs used in the management of diabetes mellitus cause hypoglycemia except?

Accepted Answer

Metformin

Answer

Tolbutamide

Answer

Glibenclamide

Answer

Glipizide

Question 3

Which of the following is a selective progesterone receptor modulator?

Accepted Answer

Ulipristal

Answer

Tamoxifen

Answer

Nomegestrol

Answer

Toremifene

Question 4

A 38-year-old male with known type 2 diabetes mellitus, treated with oral hypoglycemic drugs, presents with complaints of excessive thirst, increased urinary frequency, and a burning sensation during urination. Which of the following medications could be the cause of these symptoms?

Accepted Answer

Dapagliflozin

Answer

Exenatide

Answer

Glipizide

Answer

Metformin

Question 5

Bisphosphonates are not indicated in which of the following conditions?

Accepted Answer

Vitamin D intoxication

Answer

Hypercalcemia

Answer

Osteoporosis

Answer

Cancer-induced osteolysis

Question 6

Peripheral conversion of thyroxine (T4) to triiodothyronine (T3) is inhibited by which of the following medications?

Accepted Answer

Propranolol

Answer

Diltiazem

Answer

Sotalol

Answer

Sodium iodide

Question 7

What is the characteristic problem in females taking nor-ethisterone?

Accepted Answer

Irregular bleeding

Answer

Thromboembolism

Answer

Hirsutism

Answer

Weight gain

Question 8

Denosumab, a monoclonal antibody against RANK ligand, is used for the treatment of which condition?

Accepted Answer

Osteoporosis

Answer

Rheumatoid arthritis

Answer

Osteoarthritis

Answer

Systemic lupus erythematosus

Question 9

GnRH agonist is used in all of the following EXCEPT?

Accepted Answer

Hypoestrogenism

Answer

Delaying puberty in individuals with precocious puberty

Answer

Endometriosis

Answer

Congenital adrenal hyperplasia

Question 10

Galactorrhea may be associated with the use of all the following drugs except?

Accepted Answer

Pyridoxine

Answer

Methyldopa

Answer

Tricyclic antidepressants

Answer

Phenothiazine

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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