Endocrine Pharmacology — MCQs

Endocrine Pharmacology Indian Medical PG Practice Questions and MCQs

Question 651: What is the content of ethinyl estradiol in very low dose oral contraceptives ?

A. 20 µg (Correct Answer)
B. 15 µg
C. 25 µg
D. 30 µg

Explanation: ***20 µg*** - Very low-dose oral contraceptives typically contain **20 µg of ethinyl estradiol**. This dosage is chosen to minimize estrogen-related side effects while maintaining contraceptive efficacy. - While it offers fewer side effects, its **contraceptive reliability** might be slightly lower than standard doses, and it could lead to more **breakthrough bleeding**. *15 µg* - Oral contraceptives with **15 µg of ethinyl estradiol** are considered ultra-low dose and are less common. - This dosage carries a higher risk of **breakthrough bleeding** and potentially reduced efficacy compared to 20 µg. *25 µg* - An oral contraceptive containing **25 µg of ethinyl estradiol** falls within the low-dose range, but it is not classified as "very low dose" given that 20 µg is the typical threshold for that designation. - While still generally well-tolerated, it contains slightly more estrogen than the very low-dose options. *30 µg* - This concentration of ethinyl estradiol is characteristic of **low-dose oral contraceptives**, but not "very low dose." - It offers good contraceptive efficacy with a relatively low incidence of estrogen-related side effects.

Question 652: Consider the following list of cancers: 1. Ovarian cancer 2. Colon cancer 3. Endometrial cancer 4. Breast cancer What is the effect of combined oral contraceptive pills on the above?

A. Increased risk of 3 and 4 only
B. Protection against 1, 2 and 3 (Correct Answer)
C. Decreased risk of 1 and 2 only
D. Increased risk of 2 and 3 only

Explanation: **Protection against 1, 2, and 3** - Combined oral contraceptive (COC) pills are known to **reduce the risk of ovarian and endometrial cancer**, effects that can persist for decades after discontinuation. This is primarily due to the suppression of ovulation and the direct effect of progestin on the endometrium. - COC use also offers some **protection against colorectal cancer**, with studies showing a modest reduction in risk, potentially related to changes in bile acid metabolism or other hormonal effects. *Increased risk of 3 and 4 only* - While COCs **decrease the risk of endometrial cancer (3)**, they are associated with a **modest, temporary increase in the risk of breast cancer (4)**, which typically returns to baseline 10 years after cessation. - This option incorrectly states an increased risk for endometrial cancer and doesn't account for the protective effects on ovarian and colon cancer. *Decreased risk of 1 and 2 only* - COCs do **decrease the risk of ovarian cancer (1) and colon cancer (2)**. - However, this option is incomplete as it overlooks the significant protective effect on **endometrial cancer (3)**. *Increased risk of 2 and 3 only* - COCs actually **decrease the risk of both colon cancer (2) and endometrial cancer (3)**. - This statement directly contradicts the established protective effects of COCs on these cancer types.

Question 653: Minipill containing 75 µg of desogestrel is used for contraception. Which of the following is its schedule of administration ?

A. Taken continuously without pill-free intervals (Correct Answer)
B. Taken once a day pill for 3 months with 7 days pill free interval
C. Taken for 21 days with 7 days pill free interval
D. Taken once a day pill for 2 months with 7 days pill free interval

Explanation: **Taken continuously without pill-free intervals** - **Minipills**, containing only progestin such as desogestrel, are designed for continuous daily administration to maintain consistent progestin levels and contraceptive efficacy. - Unlike combined oral contraceptive pills, minipills do not include a **pill-free interval** as there is no estrogen component to initiate a withdrawal bleed. *Taken once a day pill for 3 months with 7 days pill free interval* - This regimen is more characteristic of **extended-cycle combined oral contraceptives** or specific progestin-only regimens not typically applied to standard minipills like desogestrel. - A 7-day pill-free interval is usually for combined oral contraceptives to allow for a **withdrawal bleed**. *Taken for 21 days with 7 days pill free interval* - This is the standard regimen for **combined oral contraceptive pills**, which contain both estrogen and progestin. - The 7-day pill-free interval allows for a **hormone withdrawal bleed**, which is not part of minipill administration. *Taken once a day pill for 2 months with 7 days pill free interval* - This schedule is not a standard administration for either **minipills** or typical combined oral contraceptives. - **Continuous use** is crucial for minipills to maintain their contraceptive effect.

Question 654: Which one of the following is not a third generation progestogen used in combined oral contraceptive pills ?

A. Norgestimate
B. Levonorgestrel (Correct Answer)
C. Gestodene
D. Desogestrel

Explanation: ***Levonorgestrel*** - **Levonorgestrel** is a **second-generation progestogen** commonly used in combined oral contraceptive pills and emergency contraception. - While effective, it tends to have higher androgenic activity compared to third-generation progestogens. *Norgestimate* - **Norgestimate** is a **third-generation progestogen** known for its lower androgenic activity. - It is often favored in combined oral contraceptives to minimize androgenic side effects like acne and hirsutism. *Gestodene* - **Gestodene** is a **third-generation progestogen** that has minimal androgenic activity and high progestational potency. - It is frequently included in modern combined oral contraceptives to improve cycle control and reduce side effects. *Desogestrel* - **Desogestrel** is also a **third-generation progestogen** and is an active metabolite of etonogestrel. - It is characterized by its low androgenic effects and is used in various combined oral contraceptive formulations.

Question 655: Post coital contraception is achieved by all except

A. By administration of RU 486
B. Administration of prostaglandins
C. High degree of progesterone (Correct Answer)
D. High dose estrogens

Explanation: ***High degree of progesterone*** - A *high degree of progesterone* is associated with **maintaining pregnancy**, not preventing it. - Progesterone supports the endometrium and maintains the corpus luteum, which are essential for pregnancy continuation. - While synthetic progestins (like levonorgestrel) are used in emergency contraception, they work through different mechanisms (ovulation inhibition, altered cervical mucus) at specific low doses, not as "high degree of progesterone" [2]. - High progesterone levels are NOT used for post-coital contraception. *By administration of RU 486* - **RU 486 (mifepristone)** is a progesterone receptor antagonist effective for post-coital contraception and medical abortion [1]. - It blocks progesterone action, causing decidual necrosis and preventing implantation or terminating early pregnancy [1]. - Commonly used as emergency contraception and for early medical abortion [1]. *Administration of prostaglandins* - **Prostaglandins** (like misoprostol) cause uterine contractions and cervical ripening [1]. - Used in combination with mifepristone for medical abortion [1]. - Can prevent implantation or induce abortion when administered post-coitally [1]. *High dose estrogens* - **High-dose estrogens** were historically used for post-coital contraception (Yuzpe regimen combined estrogen-progestin). - Work by inhibiting or delaying ovulation, interfering with corpus luteum function, and altering the endometrium to prevent implantation. - Effective when administered within 72 hours of unprotected intercourse.

Question 656: Mifepristone used for inducing abortion acts on :

A. Uterine contractility
B. Hypothalamopituitary ovarian axis
C. Progesterone receptors (Correct Answer)
D. All of the options

Explanation: ***Progesterone receptors*** - **Mifepristone** is a **progesterone receptor antagonist**, meaning it blocks the action of progesterone [1]. - In pregnancy, **progesterone** is crucial for maintaining the uterine lining and preventing contractions, so blocking its action leads to **endometrial shedding** and uterine contractions [1].*Uterine contractility* - While mifepristone ultimately affects **uterine contractility**, this is an **indirect effect** of blocking progesterone [1]. - The direct action is on the **receptors themselves**, not the contractility mechanism.*Hypothalamopituitary ovarian axis* - Mifepristone does **not primarily act** on the **hypothalamic-pituitary-ovarian axis**. - Its main effect is directly on the **uterine tissue** by blocking progesterone's local action.*All of the options* - As mifepristone's primary and direct mechanism is through **progesterone receptor antagonism**, this option is incorrect [1]. - The effects on uterine contractility are secondary to its receptor blockade.

Question 657: The following drugs can cause osteoporosis, except

A. corticosteroid
B. danazol
C. mifepristone (Correct Answer)
D. GnRH analogue

Explanation: ***Mifepristone***- **Mifepristone** is the **least commonly associated** with osteoporosis among these options in typical clinical practice, making it the best answer to this "EXCEPT" question.- While mifepristone is an anti-progestin and anti-glucocorticoid used for conditions like Cushing's syndrome, its osteoporosis risk is **less direct and less well-established** compared to the other drugs listed.- In chronic use, mifepristone can paradoxically increase cortisol levels through negative feedback disruption, which theoretically could affect bone, but this is **not a primary clinical concern** in its typical therapeutic applications.*Corticosteroid*- **Corticosteroids** are the **most common cause** of drug-induced osteoporosis (glucocorticoid-induced osteoporosis - GIOP) [1, 2].- They increase bone resorption by stimulating osteoclast activity and decrease bone formation by inhibiting osteoblast function [2].- Even short-term use can lead to rapid bone loss, with fracture risk increasing within 3-6 months of therapy.*Danazol*- **Danazol** is a synthetic androgen that causes a **hypoestrogenic state** by suppressing ovarian function.- This reduction in estrogen levels leads to **accelerated bone loss and osteoporosis**, particularly in women [1, 2].- Prolonged use requires bone density monitoring.*GnRH analogue*- **GnRH analogues** suppress sex hormone production (estrogen and testosterone) by pituitary desensitization.- The resulting **hypogonadism** directly causes **rapid bone loss** and significantly increased osteoporosis risk [1, 2].- Bone loss can occur within 6 months of therapy, often requiring prophylactic bone-protective agents.

Question 658: The mechanism of action by which clomiphene citrate induces ovulation is

A. through the hypothalamic estrogenic effect
B. through negative feedback on gonadotrophins
C. through its anti-estrogenic effect (Correct Answer)
D. through positive feedback on gonadotrophins

Explanation: ***Correct: Through its anti-estrogenic effect*** - **Clomiphene citrate** is a selective estrogen receptor modulator (SERM) that acts as an **estrogen antagonist** at the hypothalamus and pituitary gland - By blocking estrogen receptors, it prevents the hypothalamus from sensing circulating estrogen, thereby removing the **negative feedback** normally exerted by estrogen - This perceived low estrogen state triggers increased **GnRH secretion**, leading to elevated **FSH and LH release**, which stimulates follicular development and ovulation *Incorrect: Through the hypothalamic estrogenic effect* - Clomiphene citrate is an **anti-estrogen**, not an estrogen agonist at the hypothalamic level - An estrogenic effect would **enhance negative feedback**, inhibiting GnRH and gonadotropin release, thereby **suppressing** rather than inducing ovulation *Incorrect: Through negative feedback on gonadotrophins* - This is the opposite of clomiphene's mechanism - Clomiphene works by **blocking negative feedback**, not establishing it - By antagonizing estrogen receptors, it tricks the hypothalamus into perceiving low estrogen levels, leading to **increased** (not decreased) gonadotropin release *Incorrect: Through positive feedback on gonadotrophins* - While clomiphene ultimately results in increased gonadotropin release, it does so by **disrupting negative feedback**, not by directly creating positive feedback - True positive feedback occurs naturally during the late follicular phase when sustained high estrogen levels trigger the LH surge - Clomiphene's mechanism is distinct—it removes the brake (negative feedback) rather than adding an accelerator (positive feedback)

Question 659: A woman with which of the following health problems should avoid centchroman?

A. Polycystic ovarian syndrome
B. Endometriosis
C. Woman with dysfunctional uterine bleeding (Correct Answer)
D. Endometrial hyperplasia

Explanation: ***Woman with dysfunctional uterine bleeding*** *(Marked as official answer, but medically questionable)* - **Important Note:** Centchroman (Ormeloxifene) is actually **approved for treating DUB** in India and is commonly used for this indication. - Its **anti-estrogenic effect on the endometrium** helps reduce abnormal bleeding by preventing excessive proliferation. - This PYQ answer may reflect specific exam context or outdated understanding, but current medical practice uses centchroman **as a treatment for DUB**, not as a contraindication. - Students should be aware this contradicts standard therapeutic use. *Polycystic ovarian syndrome* - Centchroman is **not contraindicated** in PCOS and is sometimes used for contraception in PCOS patients. - It doesn't worsen insulin resistance and may help manage endometrial effects of unopposed estrogen. - Its anti-estrogenic effects can be beneficial in preventing endometrial hyperplasia. *Endometriosis* - Centchroman is **not contraindicated** in endometriosis. - Its **anti-estrogenic action** could theoretically reduce estrogen-dependent growth of endometrial implants. - However, progestins and GnRH agonists are preferred first-line treatments. *Endometrial hyperplasia* - Centchroman has **anti-estrogenic effects on the endometrium**, making it potentially **beneficial** rather than contraindicated. - It inhibits estrogenic stimulation and promotes endometrial shedding. - May actually be used to prevent or treat endometrial hyperplasia. **Clinical Note:** None of the listed options represent absolute contraindications to centchroman. True contraindications include pregnancy, breastfeeding, hormone-dependent cancers, and severe hepatic/renal disease.

Question 660: An overweight, hirsute woman of 30 years, with one live child presented to the family planning clinic for advice for contraception. The best suited oral contraceptive will contain the following:

A. Cyproterone acetate (Correct Answer)
B. Norgestrel
C. Medroxyprogesterone acetate
D. Norethisterone

Explanation: ***Cyproterone acetate*** - Cyproterone acetate is a **progestin with anti-androgenic properties**, making it ideal for women with hirsutism and features of hyperandrogenism, like the patient described. - It effectively reduces **androgen-related symptoms** such as hirsutism and acne, while also providing contraception. *Norgestrel* - Norgestrel is a **second-generation progestin** with some androgenic activity, which would be counterproductive for a patient with hirsutism. - It might worsen androgen-related symptoms rather than improving them. *Norethisterone* - Norethisterone (or norethindrone) is a **first-generation progestin** that also has some androgenic effects. - It is not preferred for women with hirsutism as it could exacerbate symptoms. *Medroxyprogesterone acetate* - Medroxyprogesterone acetate (MPA) is a **progestin** used in injectable contraceptives (DMPA) and oral forms, but does not possess significant anti-androgenic properties. - While it provides effective contraception, it would not address the patient's hirsutism directly.

Practice by Chapter

Hypothalamic and Pituitary Hormones

Practice Questions

Thyroid Drugs and Antithyroid Agents

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Insulin and Oral Hypoglycemic Agents

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Adrenocorticosteroids

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Sex Hormones: Estrogens and Progestins

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Androgens and Anabolic Steroids

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Hormonal Contraceptives

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Drugs Affecting Calcium Metabolism

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Drugs for Osteoporosis

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Pharmacological Management of Obesity

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