UPSC-CMS 2009 — Pharmacology

Q: Post coital contraception is achieved by all except

High degree of progesterone. ***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. [Practice more Pharmacology PYQs on OnCourse]

Q: What is the drug of choice for emergency contraception ?

Levonorgestrel only pill. ***Levonorgestrel only pill*** - **Levonorgestrel-only pills (LNG-EC)** are the most common and effective form of emergency contraception globally, available over-the-counter in many regions. - It works primarily by **inhibiting or delaying ovulation** and is most effective when taken as soon as possible after unprotected intercourse. *High dose oestrogen alone* - High-dose estrogen alone is **not used** for emergency contraception due to its high incidence of side effects like severe nausea and vomiting. - While estrogens can affect implantation, their use without progestin for EC is **ineffective and unsafe** compared to other methods. *Danazol* - **Danazol** is an attenuated androgen that was explored for emergency contraception but has been largely **abandoned** due to variable efficacy and a high incidence of side effects like androgenic effects. - It works by suppressing ovulation and endometrial development but is **inferior** to levonorgestrel or ulipristal acetate. *Yuzpe regimen (combined oral pill)* - The **Yuzpe regimen** uses a combination of estrogen and progestin from regular oral contraceptive pills, which is **less effective** and has more side effects (nausea, vomiting) than levonorgestrel-only pills. - This method requires taking **two doses 12 hours apart**, making it less convenient than single-dose levonorgestrel. [Practice more Pharmacology PYQs on OnCourse]

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

Levonorgestrel. ***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. [Practice more Pharmacology PYQs on OnCourse]

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

Taken continuously without pill-free intervals. **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. [Practice more Pharmacology PYQs on OnCourse]

Q: 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?

Protection against 1, 2 and 3. **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. [Practice more Pharmacology PYQs on OnCourse]

6 Previous Year Questions with Answers & Explanations

Questions

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Post coital contraception is achieved by all except

What is the drug of choice for emergency contraception ?

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

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

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?

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

UPSC-CMS 2009 - Pharmacology UPSC-CMS Practice Questions and MCQs

Question 1: 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 2: What is the drug of choice for emergency contraception ?

A. High dose oestrogen alone
B. Danazol
C. Levonorgestrel only pill (Correct Answer)
D. Yuzpe regimen (combined oral pill)

Explanation: ***Levonorgestrel only pill*** - **Levonorgestrel-only pills (LNG-EC)** are the most common and effective form of emergency contraception globally, available over-the-counter in many regions. - It works primarily by **inhibiting or delaying ovulation** and is most effective when taken as soon as possible after unprotected intercourse. *High dose oestrogen alone* - High-dose estrogen alone is **not used** for emergency contraception due to its high incidence of side effects like severe nausea and vomiting. - While estrogens can affect implantation, their use without progestin for EC is **ineffective and unsafe** compared to other methods. *Danazol* - **Danazol** is an attenuated androgen that was explored for emergency contraception but has been largely **abandoned** due to variable efficacy and a high incidence of side effects like androgenic effects. - It works by suppressing ovulation and endometrial development but is **inferior** to levonorgestrel or ulipristal acetate. *Yuzpe regimen (combined oral pill)* - The **Yuzpe regimen** uses a combination of estrogen and progestin from regular oral contraceptive pills, which is **less effective** and has more side effects (nausea, vomiting) than levonorgestrel-only pills. - This method requires taking **two doses 12 hours apart**, making it less convenient than single-dose levonorgestrel.

Question 3: 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 4: 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 5: 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 6: 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.