Endocrine Pharmacology Practice Questions

Q: The progestogenic emergency contraceptive pills act by:

Prevention of ovulation if not already occurred. ***Prevention of ovulation if not already occurred*** - Progestogenic emergency contraceptive pills primarily work by **delaying or inhibiting ovulation**, thereby preventing the release of an egg for fertilization. - This mechanism is effective when taken before the surge of **luteinizing hormone (LH)**, which triggers ovulation. - According to **WHO and FIGO guidelines**, this is the primary and most well-established mechanism of action. *Prevention of implantation of a fertilized egg* - Current scientific evidence from **WHO (2015)** and **ICMR guidelines** clearly establishes that progestogenic emergency contraceptives (like levonorgestrel) do **NOT prevent implantation** of a fertilized egg. - Studies show these pills are ineffective once fertilization has occurred, confirming they work solely through **pre-fertilization mechanisms** (primarily ovulation inhibition). - This distinction is important for understanding that progestogenic ECs are **contraceptives, not abortifacients**. *Induction of endometrial shedding* - This is a mechanism associated with **mifepristone (RU-486)**, an abortifacient, which causes shedding of the uterine lining, not with progestogenic emergency contraceptives. - Progestogenic emergency contraceptives do not induce endometrial shedding as their mode of action. *Modification of cervical mucus to reduce sperm penetration* - This is a known effect of **regular progestin-only contraceptives** (e.g., mini-pills taken daily) but is not the primary mechanism by which progestogenic emergency contraceptive pills prevent pregnancy. - While some cervical mucus thickening may occur, the main efficacy is due to **ovulation inhibition**, as the single high dose used in emergency contraception works differently than continuous low-dose regimens.

Q: Which of the following is a nasally acting GnRH analogue?

Nafarelin. ***Nafarelin (Correct Answer)*** - **Nafarelin** is available as a **nasal spray** (Synarel®), making it a nasally acting GnRH analogue - Administered intranasally for conditions like **endometriosis** and **central precocious puberty** - Its formulation is designed for efficient absorption through the **nasal mucosa** *Goserelin (Incorrect)* - Administered as a **subcutaneous implant** (Zoladex®) for sustained release, not nasally - Used in hormone therapy for **prostate cancer**, **breast cancer**, and **endometriosis** - Not available in nasal formulation *Triptorelin (Incorrect)* - Provided as an **intramuscular or subcutaneous injection** in sustained-release depot formulation - Used for hormone-sensitive cancers and **assisted reproductive technology** - Not formulated for **nasal administration** *Leuprolide (Incorrect)* - Administered via **subcutaneous or intramuscular injection** (Lupron®), including depot formulations - Used for prostate cancer, endometriosis, and uterine fibroids - **Not available in nasal form** for clinical use

Q: Which of the following drugs does not act on the thyroid?

Propranolol. ***Propranolol*** - **Propranolol** is a **beta-blocker** primarily used to relieve symptoms of hyperthyroidism such as palpitations, tremor, and anxiety by blocking beta-adrenergic receptors. - It does not directly affect thyroid hormone production or release, making it a symptomatic treatment rather than an antithyroid drug. *Propylthiouracil* - **Propylthiouracil (PTU)** is a **thionamide** drug that directly inhibits the synthesis of thyroid hormones by interfering with the **thyroid peroxidase enzyme**. - It also blocks the peripheral conversion of **thyroxine (T4)** to the more active **triiodothyronine (T3)**. *Sodium iodide* - High doses of **iodine**, such as **sodium iodide**, acutely inhibit thyroid hormone synthesis and release, a phenomenon known as the **Wolff-Chaikoff effect**. - It is often used in preparation for surgery in hyperthyroid patients or during thyroid storm. *Thiocyanate* - **Thiocyanate** is an **anion** that competitively inhibits the **iodide transporter (NIS)** in the thyroid gland. - By blocking the uptake of iodide into thyroid cells, it reduces the availability of iodine for thyroid hormone synthesis.

Q: The adverse effect of combined oral contraceptives among the following is:

Liver disorders. ***Liver disorders*** - Combined oral contraceptives (COCs) can cause adverse effects on the liver, including **cholestasis**, adenomas, and, rarely, **hepatocellular carcinoma**. - This is primarily due to the **estrogen component** which can affect liver metabolism and function. *Pelvic inflammatory disease (PID)* - COCs have been shown to **reduce the risk of PID** by thickening cervical mucus, which acts as a barrier to ascending infections. - PID is typically caused by sexually transmitted infections, not directly by COC use. *Weight changes* - While some women report weight changes, large-scale studies have not found a significant or consistent **causal link between COCs and weight gain**. - Any perceived weight changes are often transient or related to other factors, such as fluid retention. *Acne based on formulation* - Many COCs are actually prescribed to **treat acne** due to their anti-androgenic effects, particularly formulations with newer progestins. - While some specific older formulations might worsen acne in susceptible individuals, it is not a general adverse effect of COCs.

Q: Emmenagogues are the drugs that

Induce menstruation. ***Induce menstruation*** - **Emmenagogues** are substances that stimulate or increase menstrual flow. This definition directly aligns with their pharmacological action. - They are often used in traditional medicine for **amenorrhea** (absence of menstruation) or oligomenorrhea (infrequent menstruation). *Induce uterine contractions* - Drugs that induce uterine contractions are called **oxytocics**, such as oxytocin and prostaglandins. - While some emmenagogues might have mild uterine stimulant effects, their primary definition and purpose are to induce menstruation, not just any uterine contraction. *Increase perspiration* - Drugs that increase perspiration (sweating) are known as **diaphoretics** or sudorifics. - This effect is unrelated to the definition or action of emmenagogues. *Induce nausea* - Drugs that induce nausea are called **emetogenic** agents or emetics, and are used to induce vomiting. - This effect has no relation to the function of emmenagogues, which target the menstrual cycle.

Q: Which of the following steroids possesses maximum glucocorticoid activity?

Dexamethasone. ***Dexamethasone*** - **Dexamethasone** is a synthetic glucocorticoid with high potency, making it one of the steroids with the **maximum glucocorticoid activity** [1], [2]. - It exhibits a much longer duration of action and significantly greater anti-inflammatory effects compared to natural glucocorticoids like cortisol [2]. *Prednisolone* - **Prednisolone** is a synthetic glucocorticoid that has approximately four times the anti-inflammatory potency of cortisol [1]. - While potent, it does not reach the glucocorticoid activity levels of dexamethasone. *Cortisol* - **Cortisol** is the body's primary natural glucocorticoid, involved in stress response and metabolism [2]. - Its glucocorticoid activity serves as a baseline for comparing the potencies of other synthetic corticosteroids [2]. *Aldosterone* - **Aldosterone** is primarily a mineralocorticoid, not a glucocorticoid, with its main role being the regulation of electrolyte and water balance [2]. - It possesses minimal to no glucocorticoid activity.

Q: Which of the following statements about bromocriptine therapy is incorrect?

It is specific in suppressing only the prolactin secretion. ***It is specific in suppressing only the prolactin secretion*** - **Bromocriptine**, a dopamine agonist, is not specific to prolactin and can reduce the secretion of **growth hormone** in patients with **acromegaly**, as well as other anterior pituitary hormones. - Its action is to stimulate **dopamine receptors**, which then inhibits prolactin release. However, it can also have effects on other hormonal pathways due to the widespread nature of dopamine receptors. *It is used to inhibit inappropriate lactation with secondary amenorrhea* - **Bromocriptine** is a primary treatment for **hyperprolactinemia**, which often manifests as **galactorrhea (inappropriate lactation)** and **amenorrhea**. - By reducing **prolactin levels**, it can restore normal ovulatory cycles and cease lactation. *If pregnancy occurs there is increased incidence of multiple pregnancy* - While bromocriptine can induce ovulation in previously anovulatory women, leading to pregnancy, it is not associated with an **increased incidence of multiple pregnancies**. - The risk of **multiple births** is primarily linked to fertility treatments that stimulate multiple ovulations simultaneously, which is not the direct mechanism of bromocriptine. *Its teratogenic effect on the fetus is inconclusive* - Studies on bromocriptine use during early pregnancy have not shown a significantly increased risk of **teratogenic effects** or adverse pregnancy outcomes. - However, due to limited extensive data, especially at higher doses or prolonged use early in pregnancy, its use is typically **discontinued once pregnancy is confirmed**.

Q: A patient on tamoxifen therapy is most likely to develop which of the following?

Endometrial hyperplasia. ***Endometrial hyperplasia*** - Tamoxifen acts as an **estrogen receptor agonist** in the uterus, stimulating endometrial proliferation and increasing the risk of hyperplasia, polyps, and endometrial cancer. - This effect is particularly seen in **postmenopausal women** and is a major concern with long-term use. *Increased risk of breast cancer* - Tamoxifen is primarily used to **reduce the risk of breast cancer recurrence** and as a chemopreventive agent in high-risk individuals. - It acts as an **estrogen receptor antagonist** in breast tissue, blocking estrogen's proliferative effects. *Increased LDL cholesterol levels* - Tamoxifen typically has a favorable effect on lipids, often causing a **decrease in total and LDL cholesterol** levels. - This effect is due to its estrogenic activity in the liver. *Increased risk of myocardial infarction* - While tamoxifen can increase the risk of **thromboembolic events** (e.g., DVT, pulmonary embolism), it generally does not increase, and may even decrease, the risk of myocardial infarction due to its beneficial effects on lipid profiles. - Its overall cardiovascular risk profile is complex, but MI is not a commonly cited side effect.

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.

Question 1

The progestogenic emergency contraceptive pills act by:

Accepted Answer

Prevention of ovulation if not already occurred

Answer

Prevention of implantation of a fertilized egg

Answer

Induction of endometrial shedding

Answer

Modification of cervical mucus to reduce sperm penetration

Question 2

Which of the following is a nasally acting GnRH analogue?

Accepted Answer

Nafarelin

Answer

Triptorelin

Answer

Leuprolide

Answer

Goserelin

Question 3

Which of the following drugs does not act on the thyroid?

Accepted Answer

Propranolol

Answer

Propylthiouracil

Answer

Sodium iodide

Answer

Thiocyanate

Question 4

The adverse effect of combined oral contraceptives among the following is:

Accepted Answer

Liver disorders

Answer

Pelvic inflammatory disease (PID)

Answer

Weight changes

Answer

Acne based on formulation

Question 5

Emmenagogues are the drugs that

Accepted Answer

Induce menstruation

Answer

Induce uterine contractions

Answer

Increase perspiration

Answer

Induce nausea

Question 6

Which of the following steroids possesses maximum glucocorticoid activity?

Accepted Answer

Dexamethasone

Answer

Prednisolone

Answer

Aldosterone

Answer

Cortisol

Question 7

Which of the following statements about bromocriptine therapy is incorrect?

Accepted Answer

It is specific in suppressing only the prolactin secretion

Answer

If pregnancy occurs there is increased incidence of multiple pregnancy

Answer

It is used to inhibit inappropriate lactation with secondary amenorrhea

Answer

Its teratogenic effect on the fetus is inconclusive

Question 8

A patient on tamoxifen therapy is most likely to develop which of the following?

Accepted Answer

Endometrial hyperplasia

Answer

Increased risk of breast cancer

Answer

Increased LDL cholesterol levels

Answer

Increased risk of myocardial infarction

Question 9

Which of the following statements about nateglinide is correct?

Accepted Answer

Taken just before a meal, it limits postprandial hyperglycemia in type 2 diabetes mellitus

Answer

It is a long-acting oral hypoglycemic drug

Answer

It can be used in patients with renal impairment with caution.

Answer

It acts by blocking K+ channels in pancreatic beta-cells.

Question 10

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

Accepted Answer

Lasix

Answer

Haloperidol

Answer

Trifluoperazine

Answer

Metoclopramide

Endocrine Pharmacology — MCQs

Endocrine Pharmacology — MCQs

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