UPSC-CMS 2013 — Pharmacology

Q: Which of the following anti-hypertensive drugs is/are best avoided during pregnancy ?

Angiotensin converting enzyme inhibitors. ***Angiotensin converting enzyme inhibitors*** - **ACE inhibitors** are contraindicated in pregnancy due to their association with **fetal renal abnormalities**, **oligohydramnios**, and **fetal death**. - They can cause severe **birth defects** and are categorized as pregnancy category D drugs, meaning there is positive evidence of human fetal risk. *Nifedipine* - **Nifedipine**, a dihydropyridine calcium channel blocker, is considered a **safe** and effective antihypertensive in pregnancy. - It is frequently used for managing **hypertension** and **preterm labor** in pregnant women. *Methyldopa* - **Methyldopa** is often considered the **first-line drug** for chronic hypertension in pregnancy due to its established safety profile for both mother and fetus. - It has a long history of use and is one of the most studied antihypertensives in pregnancy. *Labetalol* - **Labetalol**, a combined alpha and beta-blocker, is also considered a **safe** and effective option for managing hypertension in pregnancy. - It is often used for **gestational hypertension** and **preeclampsia** and has a good fetal safety record. [Practice more Pharmacology PYQs on OnCourse]

Q: Complications of heparin therapy in pregnancy include all except :

Teratogenicity. ***Teratogenicity*** - **Heparin** does not cross the placenta due to its large molecular weight, making it a safe anticoagulant choice during pregnancy regarding fetal malformations. - Therefore, it is **not associated with teratogenicity**, unlike some other anticoagulants like warfarin. *Thrombocytopaenia* - **Heparin-induced thrombocytopenia (HIT)** is a known complication, where antibodies against heparin-platelet factor 4 complexes lead to platelet activation and consumption. - While typically Type II HIT is more severe, a mild, transient drop in platelet count (Type I) can also occur. *Osteoporosis* - **Long-term heparin therapy**, particularly unfractionated heparin, is associated with an increased risk of bone demineralization and **osteoporosis** due to its direct effect on osteoblasts and osteoclasts. - This complication is less common with low molecular weight heparin (LMWH) but still a potential concern. *Bleeding* - As an anticoagulant, **heparin's primary mechanism of action** involves inhibiting coagulation factors, which inherently increases the risk of **bleeding**. - The risk of bleeding can range from minor ecchymoses to life-threatening hemorrhages depending on the dose and individual patient factors. [Practice more Pharmacology PYQs on OnCourse]

Q: Misoprostol can be used in obstetric practice by the following routes except:

Intravenous. ***Intravenous*** - Misoprostol is **not used intravenously** in obstetric practice due to safety concerns - IV administration could lead to **rapid, uncontrolled systemic effects** including severe adverse events like **cardiovascular collapse** and anaphylactoid reactions - The drug formulation is not intended for IV use, and its rapid absorption via this route would pose significant maternal risk - All approved obstetric uses employ **oral, sublingual, vaginal, or buccal routes** *Vaginal* - Vaginal administration is commonly used in obstetrics for **cervical ripening** and **labor induction** - Also used for **management of miscarriage** and **postpartum hemorrhage** - Allows for **gradual absorption** with local effect on the cervix and uterus *Sub-lingual* - Sublingual misoprostol is effectively absorbed through the **oral mucosa** - Used for **labor induction** and **management of postpartum hemorrhage** - Offers **rapid onset of action** and bypasses first-pass metabolism *Oral* - Oral administration is used for **medical abortion**, **miscarriage management**, and **labor induction** - Also approved for prevention of **NSAID-induced gastric ulcers** (non-obstetric indication) - Absorption is slower with lower peak concentrations compared to sublingual or vaginal routes [Practice more Pharmacology PYQs on OnCourse]

Q: Mifepristone used for inducing abortion acts on :

Progesterone receptors. ***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. [Practice more Pharmacology PYQs on OnCourse]

Q: The total osmolarity of new oral rehydration solution formulation is:

245 mmol/litre. ***245 mmol/litre*** - The **New Oral Rehydration Solution (ORS)** formulation has a reduced osmolarity of **245 mOsm/L** compared to the original WHO ORS. - This reduced osmolarity aims to minimize stool output and vomiting, making it more effective for treating dehydration in children with acute diarrhea. *210 mmol/litre* - This osmolarity is lower than the recommended new ORS formulation and could potentially lead to a higher risk of **hyponatremia** if not carefully monitored. - While lower osmolarity solutions can reduce stool output, a substantially lower value might compromise adequate rehydration. *300 mmol/litre* - This value is characteristic of the **original WHO ORS** formulation, which had a higher osmolarity. - Higher osmolarity solutions, like the original ORS, can sometimes worsen diarrhea by drawing water into the lumen due to osmotic effects. *255 mmol/litre* - This osmolarity is slightly above the recommended **245 mOsm/L** for the new ORS formulation. - While possibly still effective, the optimal balance between efficacy and minimizing stool volume has been established with the 245 mOsm/L formulation. [Practice more Pharmacology PYQs on OnCourse]

7 Previous Year Questions with Answers & Explanations

Questions

All Subjects Anatomy (4)Community Medicine (23)Forensic Medicine (1)Internal Medicine (8)Microbiology (1)Obstetrics and Gynecology (31)Ophthalmology (1)Orthopaedics (3)Pathology (3)Pediatrics (2)Pharmacology (7)Physiology (5)Psychiatry (1)Radiology (1)Surgery (17)

Which of the following anti-hypertensive drugs is/are best avoided during pregnancy ?

Complications of heparin therapy in pregnancy include all except :

Misoprostol can be used in obstetric practice by the following routes except:

Mifepristone used for inducing abortion acts on :

The total osmolarity of new oral rehydration solution formulation is:

Toxic shock syndrome occurs after one of the following vaccinations :

Which of the following is an absolute contraindication for combined contraceptive oral pills ?

UPSC-CMS 2013 - Pharmacology UPSC-CMS Practice Questions and MCQs

Question 1: Which of the following anti-hypertensive drugs is/are best avoided during pregnancy ?

A. Nifedipine
B. Methyldopa
C. Labetalol
D. Angiotensin converting enzyme inhibitors (Correct Answer)

Explanation: ***Angiotensin converting enzyme inhibitors*** - **ACE inhibitors** are contraindicated in pregnancy due to their association with **fetal renal abnormalities**, **oligohydramnios**, and **fetal death**. - They can cause severe **birth defects** and are categorized as pregnancy category D drugs, meaning there is positive evidence of human fetal risk. *Nifedipine* - **Nifedipine**, a dihydropyridine calcium channel blocker, is considered a **safe** and effective antihypertensive in pregnancy. - It is frequently used for managing **hypertension** and **preterm labor** in pregnant women. *Methyldopa* - **Methyldopa** is often considered the **first-line drug** for chronic hypertension in pregnancy due to its established safety profile for both mother and fetus. - It has a long history of use and is one of the most studied antihypertensives in pregnancy. *Labetalol* - **Labetalol**, a combined alpha and beta-blocker, is also considered a **safe** and effective option for managing hypertension in pregnancy. - It is often used for **gestational hypertension** and **preeclampsia** and has a good fetal safety record.

Question 2: Complications of heparin therapy in pregnancy include all except :

A. Teratogenicity (Correct Answer)
B. Thrombocytopaenia
C. Osteoporosis
D. Bleeding

Explanation: ***Teratogenicity*** - **Heparin** does not cross the placenta due to its large molecular weight, making it a safe anticoagulant choice during pregnancy regarding fetal malformations. - Therefore, it is **not associated with teratogenicity**, unlike some other anticoagulants like warfarin. *Thrombocytopaenia* - **Heparin-induced thrombocytopenia (HIT)** is a known complication, where antibodies against heparin-platelet factor 4 complexes lead to platelet activation and consumption. - While typically Type II HIT is more severe, a mild, transient drop in platelet count (Type I) can also occur. *Osteoporosis* - **Long-term heparin therapy**, particularly unfractionated heparin, is associated with an increased risk of bone demineralization and **osteoporosis** due to its direct effect on osteoblasts and osteoclasts. - This complication is less common with low molecular weight heparin (LMWH) but still a potential concern. *Bleeding* - As an anticoagulant, **heparin's primary mechanism of action** involves inhibiting coagulation factors, which inherently increases the risk of **bleeding**. - The risk of bleeding can range from minor ecchymoses to life-threatening hemorrhages depending on the dose and individual patient factors.

Question 3: Misoprostol can be used in obstetric practice by the following routes except:

A. Vaginal
B. Sub-lingual
C. Oral
D. Intravenous (Correct Answer)

Explanation: ***Intravenous*** - Misoprostol is **not used intravenously** in obstetric practice due to safety concerns - IV administration could lead to **rapid, uncontrolled systemic effects** including severe adverse events like **cardiovascular collapse** and anaphylactoid reactions - The drug formulation is not intended for IV use, and its rapid absorption via this route would pose significant maternal risk - All approved obstetric uses employ **oral, sublingual, vaginal, or buccal routes** *Vaginal* - Vaginal administration is commonly used in obstetrics for **cervical ripening** and **labor induction** - Also used for **management of miscarriage** and **postpartum hemorrhage** - Allows for **gradual absorption** with local effect on the cervix and uterus *Sub-lingual* - Sublingual misoprostol is effectively absorbed through the **oral mucosa** - Used for **labor induction** and **management of postpartum hemorrhage** - Offers **rapid onset of action** and bypasses first-pass metabolism *Oral* - Oral administration is used for **medical abortion**, **miscarriage management**, and **labor induction** - Also approved for prevention of **NSAID-induced gastric ulcers** (non-obstetric indication) - Absorption is slower with lower peak concentrations compared to sublingual or vaginal routes

Question 4: 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 5: The total osmolarity of new oral rehydration solution formulation is:

A. 210 mmol/litre
B. 245 mmol/litre (Correct Answer)
C. 300 mmol/litre
D. 255 mmol/litre

Explanation: ***245 mmol/litre*** - The **New Oral Rehydration Solution (ORS)** formulation has a reduced osmolarity of **245 mOsm/L** compared to the original WHO ORS. - This reduced osmolarity aims to minimize stool output and vomiting, making it more effective for treating dehydration in children with acute diarrhea. *210 mmol/litre* - This osmolarity is lower than the recommended new ORS formulation and could potentially lead to a higher risk of **hyponatremia** if not carefully monitored. - While lower osmolarity solutions can reduce stool output, a substantially lower value might compromise adequate rehydration. *300 mmol/litre* - This value is characteristic of the **original WHO ORS** formulation, which had a higher osmolarity. - Higher osmolarity solutions, like the original ORS, can sometimes worsen diarrhea by drawing water into the lumen due to osmotic effects. *255 mmol/litre* - This osmolarity is slightly above the recommended **245 mOsm/L** for the new ORS formulation. - While possibly still effective, the optimal balance between efficacy and minimizing stool volume has been established with the 245 mOsm/L formulation.

Question 6: Toxic shock syndrome occurs after one of the following vaccinations :

A. DPT (Correct Answer)
B. Measles vaccine
C. BCG vaccine
D. Recombinant DNA Vaccine against Hepatitis B

Explanation: ***DPT*** - Toxic shock syndrome has been **extremely rarely reported in isolated case reports following DPT** (diphtheria, pertussis, tetanus) vaccination, though it is **not a recognized or established complication** in standard medical literature. - The association is controversial and based on very limited data. Any potential link may be related to coincidental bacterial infection rather than a direct vaccine effect. - Among the options listed, this has the most (though minimal) reported association with **TSS-like reactions** in historical case reports. *Measles vaccine* - The measles vaccine is a **live attenuated vaccine** and does not cause toxic shock syndrome. - Its adverse effects are usually related to a mild form of the disease or allergic reactions, not **bacterial toxin-mediated illnesses like TSS**. *BCG vaccine* - The BCG (Bacille Calmette-Guérin) vaccine is used against tuberculosis and is a **live attenuated vaccine**. - Adverse effects are commonly local reactions or disseminated BCG disease in immunocompromised individuals, not **toxic shock syndrome**. *Recombinant DNA Vaccine against Hepatitis B* - Recombinant DNA vaccines, like the Hepatitis B vaccine, are highly purified and contain **no live pathogens or bacterial toxins**. - They are associated with very few severe adverse events, none of which include **toxic shock syndrome**.

Question 7: Which of the following is an absolute contraindication for combined contraceptive oral pills ?

A. Migraine without aura
B. Previous history of thrombo-embolism (Correct Answer)
C. Diabetes mellitus
D. Gall bladder disease

Explanation: ***Previous history of thrombo-embolism*** - A history of **thromboembolism** significantly increases the risk of recurrent events with combined oral contraceptive pills (COCs) due to their procoagulant effects [1, 2]. - COCs contain **estrogen**, which can enhance the synthesis of clotting factors and decrease natural anticoagulants, making them absolutely contraindicated in this setting [1]. *Migraine without aura* - **Migraine without aura** is generally considered a relative contraindication or a condition requiring careful consideration, not an absolute contraindication, for combined oral contraceptive pills. - The risk of **stroke** is slightly elevated in women with migraine without aura using COCs, but it is not as high as with migraine with aura. *Diabetes mellitus* - **Diabetes mellitus** itself is not an absolute contraindication for combined oral contraceptive pills, especially if it is well-controlled and there are no vascular complications. - However, in cases of diabetes with **vascular complications** (e.g., nephropathy, retinopathy, neuropathy) or of >20 years' duration, COCs are generally contraindicated. *Gall bladder disease* - While combined oral contraceptive pills can increase the risk of **gallstone formation**, especially in susceptible individuals, it is not considered an absolute contraindication. - The effect is linked to **estrogen-induced changes** in bile composition, but careful monitoring is usually sufficient rather than absolute avoidance.