Endocrine Pharmacology Practice Questions

Q: A vasopressin analogue does not produce a therapeutic effect through the vasopressin V-2 receptor in which of the following conditions?

Bleeding esophageal varices. **Explanation:** The therapeutic effect of vasopressin analogues depends on which receptor subtype is targeted: **V1 receptors** (located on vascular smooth muscle, causing vasoconstriction) or **V2 receptors** (located in the renal collecting ducts for water reabsorption and on vascular endothelium to trigger factor release) [1]. **Why Option B is correct:** In **Bleeding Esophageal Varices**, the goal is to reduce portal venous pressure. Vasopressin analogues (specifically **Terlipressin**) act via **V1 receptors** to cause splanchnic vasoconstriction, thereby reducing blood flow into the portal system. This effect is independent of the V2 receptor. **Why the other options are incorrect:** * **Central Diabetes Insipidus (A):** Desmopressin (a selective V2 agonist) is the drug of choice. it acts on **V2 receptors** in the renal collecting ducts to increase water permeability via aquaporin-2 channels [1]. * **Type 1 von Willebrand’s Disease (C):** Desmopressin acts on **V2 receptors** on vascular endothelial cells to stimulate the release of stored von Willebrand factor (vWF) and Factor VIII. * **Primary Nocturnal Enuresis (D):** Desmopressin is used to decrease urine production overnight by activating renal **V2 receptors**, helping children who have a nocturnal deficiency of ADH. **High-Yield NEET-PG Pearls:** * **Desmopressin (dDAVP):** Highly selective for **V2**; preferred for DI and bleeding disorders because it lacks the pressor (V1) side effects. * **Terlipressin:** Selective for **V1**; drug of choice for Hepatorenal Syndrome and Variceal bleeding. * **V3 Receptors:** Located in the anterior pituitary; they mediate the release of ACTH [1]. * **Side Effect:** Hyponatremia is a critical risk when using V2 agonists like Desmopressin.

Q: Which regimen of corticosteroids has the maximum potential for adverse effects?

Prednisolone 20 mg/day orally for one year. **Explanation** The adverse effects of corticosteroids are determined by two primary factors: the **potency/dose** and, more significantly, the **duration of therapy**. **Why Option D is Correct:** The potential for serious systemic side effects—such as **Hypothalamic-Pituitary-Adrenal (HPA) axis suppression**, iatrogenic Cushing’s syndrome, osteoporosis, cataracts, and opportunistic infections—is directly proportional to the **chronicity of use**. While 20 mg of Prednisolone is a moderate dose, administering it daily for **one year** ensures prolonged exposure, leading to cumulative toxicity and permanent physiological changes. Any course exceeding 2-3 weeks carries a significantly higher risk than high-dose short bursts. **Analysis of Incorrect Options:** * **Options A & B:** These represent short-term "burst" therapies (7 days and 3 days, respectively). Short courses (less than 2 weeks), even at relatively high doses, rarely cause HPA axis suppression or permanent metabolic side effects. * **Option C:** This is "Pulse Therapy." While 1000 mg is a massive dose, a single or limited pulse (usually 3 days) is generally better tolerated in terms of long-term systemic toxicity compared to chronic daily administration, as the body has time to recover after the pulse. **Clinical Pearls for NEET-PG:** * **HPA Suppression:** Occurs if steroids are used for >2 weeks. Tapering is mandatory in such cases to avoid adrenal crisis. * **Mineralocorticoid Potency:** Fludrocortisone > Aldosterone > Hydrocortisone. (Prednisolone and Dexamethasone have minimal to no salt-retaining activity). * **Anti-inflammatory Potency:** Dexamethasone (30) > Methylprednisolone (5) > Prednisolone (4) > Hydrocortisone (1). * **Most common side effect of inhaled steroids:** Oropharyngeal candidiasis (prevented by using a spacer or rinsing the mouth).

Q: Lactation is suppressed by which of the following medications?

Apomorphine. ### Explanation The regulation of prolactin secretion is primarily under the inhibitory control of **Dopamine**, which acts on **D2 receptors** in the anterior pituitary. Dopamine is often referred to as the Prolactin Inhibiting Hormone (PIH). **Why Apomorphine is Correct:** Apomorphine is a potent **Dopamine agonist**. By stimulating D2 receptors, it mimics the action of endogenous dopamine, thereby inhibiting the release of prolactin from the lactotrophs. Reduced prolactin levels lead to the suppression of lactation. While Bromocriptine and Cabergoline are more commonly used clinically for this purpose, Apomorphine functions via the same pharmacological mechanism. **Analysis of Incorrect Options:** * **Metoclopramide (A) & Haloperidol (D):** Both are **D2 receptor antagonists**. By blocking the inhibitory effect of dopamine, they cause a rise in prolactin levels (hyperprolactinemia), which can lead to galactorrhea (inappropriate milk production) rather than suppression. * **Opioids (B):** Opioids inhibit the release of dopamine from the hypothalamus. By decreasing the "inhibitory brake," they indirectly increase prolactin secretion. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** **Cabergoline** is currently the drug of choice for suppressing lactation and treating prolactinomas due to its higher efficacy and longer half-life compared to Bromocriptine. * **Physiological Inhibitor:** Dopamine is the only major hormone that is primarily regulated by inhibition rather than stimulation. * **Antipsychotic Side Effect:** Hyperprolactinemia is a common side effect of typical antipsychotics (like Haloperidol) and can cause gynecomastia in males and amenorrhea in females.

Q: Clomiphene acts to induce ovulation by which mechanisms?

Diminishing ER-mediated negative feedback at the pituitary. **Explanation:** **Mechanism of Action:** Clomiphene Citrate (CC) is a Selective Estrogen Receptor Modulator (SERM). Its primary mechanism for inducing ovulation is its **anti-estrogenic effect** on the hypothalamic-pituitary-ovarian axis. The correct answer is **A** because Clomiphene binds to estrogen receptors (ER) in the **pituitary and hypothalamus**, occupying them for extended periods. This prevents endogenous estrogen from exerting its normal **negative feedback**. The brain "perceives" low estrogen levels, leading to a compensatory increase in the pulse frequency of **GnRH** and a subsequent rise in **FSH and LH** from the anterior pituitary. This "FSH window" expansion stimulates follicular development in the ovary. **Why other options are incorrect:** * **B & C:** Clomiphene acts as an **antagonist** (not an agonist) at the level of the hypothalamus and pituitary. It decreases/blocks the action of ER alpha rather than increasing it. * **D:** Clomiphene works by **depleting** or downregulating the total number of available estrogen receptors over time, not by increasing the amount of ER alpha. **High-Yield Clinical Pearls for NEET-PG:** * **First-line drug:** Historically the first-line for WHO Group II ovulation induction (PCOS), though **Letrozole** (Aromatase Inhibitor) is now preferred due to higher live birth rates. * **Anti-estrogenic side effects:** It has an undesirable thinning effect on the **endometrium** and thickens the **cervical mucus**, which may hinder implantation/sperm penetration. * **Risk:** Associated with a 5–10% risk of **multiple pregnancies** (primarily twins) and Ovarian Hyperstimulation Syndrome (OHSS). * **Administration:** Usually started on Day 2, 3, 4, or 5 of the menstrual cycle for 5 days.

Q: What is true regarding the use of bromocriptine for suppression of lactation?

It can cause hypotension.. **Explanation:** Bromocriptine is a dopamine agonist (D2 receptor agonist) that inhibits the release of prolactin from the anterior pituitary. While it was historically the drug of choice for lactation suppression, its use has significantly declined due to its side effect profile. **Why Option B is Correct:** Bromocriptine causes peripheral vasodilation and inhibits the sympathetic nervous system, frequently leading to **orthostatic hypotension** and dizziness. In severe cases, it can cause significant drops in blood pressure, which is particularly concerning in the immediate postpartum period when hemodynamic shifts are already occurring. **Analysis of Incorrect Options:** * **Option A:** Bromocriptine is actually associated with an increased risk of **thromboembolic events** (like stroke and myocardial infarction) and hypertension/seizures in postpartum women, rather than DVT specifically. However, the risk of cardiovascular accidents led the FDA to withdraw its indication for routine lactation suppression. * **Option C:** Metoclopramide is a **dopamine antagonist**. Therefore, it antagonizes (blocks) the effect of bromocriptine rather than potentiating it. * **Option D:** To prevent rebound lactation, bromocriptine must be administered for **14 days (2 weeks)**. A 1-week course is insufficient. **NEET-PG High-Yield Pearls:** * **Drug of Choice:** Currently, **Cabergoline** (a long-acting D2 agonist) is the preferred drug for lactation suppression because it is more effective, has a longer half-life, and carries fewer side effects than bromocriptine. * **Dosage:** Cabergoline is typically given as a single dose (1 mg) within 24 hours of delivery. * **Non-Pharmacological:** For many women, breast binding, ice packs, and avoiding nipple stimulation are safer alternatives for suppression.

Q: Which of the following drugs halts both macrovascular and microvascular effects of diabetes mellitus?

Biguanides. **Explanation:** **Biguanides (Metformin)** are the first-line agents in Type 2 Diabetes Mellitus because they are uniquely cardioprotective. Unlike many other antidiabetics, Metformin reduces **macrovascular complications** (Myocardial Infarction, Stroke) and **microvascular complications** (Retinopathy, Nephropathy, Neuropathy). This is primarily due to its ability to improve insulin sensitivity, reduce LDL/VLDL levels, and decrease plasminogen activator inhibitor-1 (PAI-1), which provides a fibrinolytic benefit. The landmark UKPDS study confirmed Metformin’s role in reducing cardiovascular mortality. **Analysis of Incorrect Options:** * **Acarbose (Alpha-glucosidase inhibitor):** Primarily reduces postprandial hyperglycemia. While it may have some benefit in reducing cardiovascular events (STOP-NIDDM trial), its evidence for halting long-term microvascular complications is significantly weaker than Metformin. * **Meglitinides (Repaglinide):** These are short-acting insulin secretagogues. They effectively control glucose spikes but have not demonstrated a definitive reduction in macrovascular outcomes or long-term mortality. * **Alogliptin (DPP-4 Inhibitor):** While "cardiovascularly safe" (EXAMINE trial), DPP-4 inhibitors generally show a neutral effect on macrovascular outcomes rather than a significant reduction in mortality compared to Metformin or SGLT2 inhibitors. **NEET-PG High-Yield Pearls:** * **Mechanism:** Activates AMP-activated protein kinase (AMPK), leading to decreased hepatic gluconeogenesis. * **Side Effects:** Most common is GI upset; most serious is **Lactic Acidosis** (avoid if Creatinine >1.5 mg/dL). * **Weight Neutrality:** Metformin is often associated with modest weight loss, unlike Sulfonylureas or Insulin which cause weight gain. * **Vitamin Deficiency:** Long-term use can lead to **Vitamin B12 deficiency**.

Q: Which of the following is an oxytocin antagonist?

Atosiban. **Explanation:** **Atosiban** is the correct answer because it is a competitive **oxytocin receptor antagonist**. It works by blocking oxytocin receptors in the myometrium, thereby inhibiting uterine contractions. Clinically, it is used as a **tocolytic** agent to delay imminent preterm birth in pregnant women, providing a window to administer corticosteroids for fetal lung maturity. **Analysis of Incorrect Options:** * **Ritodrine & Isoxsuprine (Options A & C):** These are **$\beta_2$-adrenergic agonists**. While they are also used as tocolytics, their mechanism involves stimulating $\beta_2$ receptors to increase intracellular cAMP, leading to uterine relaxation. They are not oxytocin antagonists. * **Methergine (Methylergometrine) (Option D):** This is an **ergot alkaloid**. Unlike Atosiban, it is an **oxytocic** agent (uterine stimulant). It causes intense, prolonged uterine contractions and is used primarily to prevent or treat Postpartum Hemorrhage (PPH). It is strictly contraindicated in pregnancy before delivery. **High-Yield NEET-PG Pearls:** * **Atosiban's Advantage:** It has a more favorable side-effect profile compared to $\beta$-agonists (which cause tachycardia, tremors, and hyperglycemia). * **Drug of Choice (DOC):** Currently, **Nifedipine** (a Calcium Channel Blocker) is often preferred over Atosiban and Ritodrine as a first-line tocolytic due to its oral efficacy and safety profile. * **Contraindication:** Do not use Methergine in patients with **hypertension** or Preeclampsia, as it can cause a dangerous rise in blood pressure.

Q: Which of the following is NOT caused by glucocorticoids?

Hypoglycemia. Glucocorticoids (like cortisol) are essential metabolic hormones, but their chronic use or excess leads to a distinct pattern of adverse effects. ### **Why Hypoglycemia is the Correct Answer** Glucocorticoids are **diabetogenic**. They **increase blood glucose levels** (Hyperglycemia) through three primary mechanisms: 1. **Increased Gluconeogenesis:** Stimulating the liver to produce glucose from non-carbohydrate sources. 2. **Increased Glycogenolysis:** Breakdown of stored glycogen. 3. **Peripheral Insulin Resistance:** Decreasing glucose uptake by peripheral tissues (muscle and fat). Therefore, they cause **hyperglycemia**, not hypoglycemia. Steroid-induced diabetes is a common clinical complication. ### **Explanation of Incorrect Options** * **A. Osteoporosis:** Glucocorticoids inhibit osteoblast activity, stimulate osteoclasts, and decrease intestinal calcium absorption. This makes osteoporosis the most common drug-induced bone disease. * **C. Peptic Ulceration:** They reduce protective prostaglandin synthesis in the gastric mucosa and can mask the symptoms of a perforation. The risk is significantly higher when combined with NSAIDs. * **D. Cataracts:** Chronic use is a well-known cause of **posterior subcapsular cataracts** and can also increase intraocular pressure (glaucoma). ### **High-Yield NEET-PG Pearls** * **Mnemonic for Side Effects:** "CUSHINGOID" (Cataracts, Ulcers, Skin thinning, Hypertension/Hirsutism, Immunosuppression, Necrosis of femoral head, Glucose elevation, Osteoporosis, Impaired wound healing, Depression/Psychosis). * **Electrolyte Changes:** Glucocorticoids cause **Hypokalemia** and **Hypernatremia** (due to mild mineralocorticoid activity). * **Hematological Effects:** They cause **Lymphopenia** and **Eosinopenia**, but **Neutrophilia** (due to demargination of neutrophils from blood vessel walls).

Q: Which of the following is an absolute contraindication to adrenal steroid therapy?

Cushing's syndrome. ### Explanation **Correct Option: D. Cushing's syndrome** The fundamental principle of steroid therapy is to avoid exogenous administration when there is already an endogenous excess. **Cushing’s syndrome** is characterized by chronic hypercortisolism. Administering exogenous corticosteroids in this state would exacerbate the clinical manifestations (e.g., central obesity, muscle wasting, skin thinning) and significantly increase the risk of life-threatening complications like hypertensive crisis or severe metabolic derangement. Therefore, it is considered an **absolute contraindication**. **Analysis of Incorrect Options:** * **A, B, and C (Hypertension, Osteoporosis, Diabetes mellitus):** These are **relative contraindications**. While steroids can worsen these conditions (by causing sodium retention, increasing bone resorption, and inducing hyperglycemia), they are not strictly prohibited. If a patient with these comorbidities has a life-threatening or severe inflammatory condition (e.g., Status Asthmaticus or Pemphigus Vulgaris), steroids may still be administered under close monitoring and pharmacological control of the underlying comorbidity. **High-Yield Clinical Pearls for NEET-PG:** * **Other Absolute Contraindications:** Systemic fungal infections (steroids mask symptoms and allow dissemination) and Herpes Simplex Keratitis (risk of corneal perforation). * **Withdrawal:** Long-term steroid therapy must never be stopped abruptly due to **HPA-axis suppression**; doing so can precipitate an acute adrenal crisis. * **Steroid-Induced Myopathy:** Characterized by proximal muscle weakness; notably, the heart muscle is spared. * **Glucocorticoid of choice in pregnancy:** **Prednisolone** (it is inactivated by placental 11β-HSD2, protecting the fetus). If fetal lung maturity is the goal, use **Betamethasone** or **Dexamethasone** as they cross the placenta.

Question 1

A vasopressin analogue does not produce a therapeutic effect through the vasopressin V-2 receptor in which of the following conditions?

Accepted Answer

Bleeding esophageal varices

Answer

Central diabetes insipidus

Answer

Type 1 von Willebrand's disease

Answer

Primary nocturnal enuresis

Question 2

True about lispro-insulin is:

Accepted Answer

Action is faster and of longer duration than regular insulin.

Answer

Action is faster and short in duration than regular insulin.

Answer

It is given 15 minutes prior to a meal.

Answer

Source is lamb.

Question 3

Which regimen of corticosteroids has the maximum potential for adverse effects?

Accepted Answer

Prednisolone 20 mg/day orally for one year

Answer

Prednisolone 60 mg/day orally for 7 days

Answer

Dexamethasone 4 mg intravenous daily for 3 days

Answer

Methylprednisolone 1000 mg intravenous twice single dose

Question 4

Lactation is suppressed by which of the following medications?

Accepted Answer

Apomorphine

Answer

Metaclopramide

Answer

Opioids

Answer

Haloperidol

Question 5

Clomiphene acts to induce ovulation by which mechanisms?

Accepted Answer

Diminishing ER-mediated negative feedback at the pituitary

Answer

Increasing the action of ER alpha in the ovary

Answer

Increasing the action of ER alpha in the hypothalamus

Answer

Increasing the amount of ER alpha

Question 6

What is true regarding the use of bromocriptine for suppression of lactation?

Accepted Answer

It can cause hypotension.

Answer

It can cause deep vein thrombosis.

Answer

Metoclopramide potentiates the action of bromocriptine.

Answer

It is given for 1 week only.

Question 7

Which of the following drugs halts both macrovascular and microvascular effects of diabetes mellitus?

Accepted Answer

Biguanides

Answer

Acarbose

Answer

Meglitinide

Answer

Algaliptin

Question 8

Which of the following is an oxytocin antagonist?

Accepted Answer

Atosiban

Answer

Ritodrine

Answer

Isoxsuprine

Answer

Methergine

Question 9

Which of the following is NOT caused by glucocorticoids?

Accepted Answer

Hypoglycemia

Answer

Osteoporosis

Answer

Peptic ulceration

Answer

Cataracts

Question 10

Which of the following is an absolute contraindication to adrenal steroid therapy?

Accepted Answer

Cushing's syndrome

Answer

Severe hypertension

Answer

Osteoporosis

Answer

Diabetes mellitus

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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