UPSC-CMS 2021 — Pharmacology

Q: Which of the following statements regarding the composition of common crystalloid solutions is correct ?

Normal saline contains 154 mEq/L of Na+. ***Normal saline contains 154 mEq/L of Na+*** - Normal saline (0.9% NaCl) contains **154 mEq/L of both Na+ and Cl-**, making this statement factually correct. - This makes normal saline **hypernatremic and hyperchloremic** compared to plasma (which has ~140 mEq/L Na+ and ~103 mEq/L Cl-). - Normal saline is useful for correcting **hyponatremia** and for significant volume expansion, but large volumes can cause **hyperchloremic metabolic acidosis**. *Hartmann's solution contains 140 mEq/L of Na+* - Hartmann's solution (Lactated Ringer's) actually contains approximately **130 mEq/L of Na+**, not 140 mEq/L. - The sodium content is designed to be closer to that of **plasma**, making it a more physiologically balanced solution. *Hartmann's solution contains 120 mEq/L of Cl-* - Hartmann's solution contains approximately **109-110 mEq/L of Cl-**, not 120 mEq/L. - This **lower chloride content** compared to normal saline, along with the presence of lactate (28 mEq/L), contributes to a reduced risk of hyperchloremic metabolic acidosis. - The lactate is metabolized to bicarbonate, providing a mild alkalinizing effect. *Normal saline contains 140 mEq/L of Cl-* - Normal saline contains **154 mEq/L of Cl-**, not 140 mEq/L. - Its high chloride content can lead to **hyperchloremic metabolic acidosis** with large-volume administration. [Practice more Pharmacology PYQs on OnCourse]

Q: Which one of the following statements regarding the composition of common crystalloid solutions is correct ?

Hartmann’s solution contains 111 meq/L of Cl. ***Hartmann’s solution contains 111 meq/L of Cl*** - **Hartmann's solution** (Lactated Ringer's) typically contains **111 mmol/L** (or meq/L) of chloride. - Its electrolyte composition aims to mimic plasma more closely than normal saline, with **lower chloride content** to reduce the risk of hyperchloremic acidosis. *Hartmann’s solution contains 111 meq/L of Na* - Hartmann's solution contains approximately **130 meq/L of Na**, not 111 meq/L. - The sodium concentration is higher than 111 meq/L to maintain **isotonicity** and match plasma osmolality. *Normal saline contains 130 meq/L of Cl* - **Normal saline (0.9% NaCl)** contains **154 meq/L of Cl**, which is significantly higher than 130 meq/L. - Its high chloride content can lead to **hyperchloremic metabolic acidosis** if administered in large volumes. *Normal saline contains 100 meq/L of Na* - **Normal saline (0.9% NaCl)** contains **154 meq/L of Na**, not 100 meq/L [1]. - This higher sodium concentration contributes to its **isotonicity** with plasma [1]. [Practice more Pharmacology PYQs on OnCourse]

Q: Consider the following in respect of Ormeloxifene : 1. It is a research product of Central Drug Research Institute, Lucknow 2. It is a steroidal compound 3. It is a potent antiestrogen with weak estrogenic properties 4. It does not inhibit ovulation Which of the above are correct ?

1, 3 and 4. ***1, 3 and 4*** - Ormeloxifene, also known as **Centchroman**, was developed by the **Central Drug Research Institute (CDRI), Lucknow**, making statement 1 **correct**. - It is a **selective estrogen receptor modulator (SERM)** that acts as a **potent antiestrogen** in the uterus and breast, with **weak estrogenic activity** in other tissues like bone, thus statement 3 is **correct**. - Ormeloxifene has a **unique mechanism** among contraceptives: it **does not inhibit ovulation**. Instead, it works by **preventing implantation** through endometrial changes and altering cervical mucus, making statement 4 **correct**. - Statement 2 is **incorrect** because Ormeloxifene is a **non-steroidal compound**, not a steroidal one. *1, 2 and 3* - This option is incorrect because statement 2, claiming Ormeloxifene is a **steroidal compound**, is false. Ormeloxifene is a **non-steroidal SERM**. - While statements 1 and 3 are correct, the inclusion of incorrect statement 2 makes this option wrong. *1 and 3 only* - While statements 1 and 3 are indeed correct, this option is **incomplete** as it excludes statement 4. - Statement 4 is also correct—Ormeloxifene **does not inhibit ovulation**, which is a key distinguishing feature of this contraceptive. *2, 3 and 4* - This option is incorrect because statement 2 is false—Ormeloxifene is **non-steroidal**, not steroidal. - Although statements 3 and 4 are correct, the inclusion of the false statement 2 makes this entire option incorrect. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following drugs should be avoided in the first-line ART regimens because of its well recognized metabolic toxicities ?

Stavudine (d4T). ***Stavudine (d4T)*** - **Stavudine** is a **nucleoside reverse transcriptase inhibitor (NRTI)** that is well-known for its significant **metabolic toxicities**, including **lipoatrophy**, peripheral neuropathy, and lactic acidosis [1]. - Due to these severe side effects, it is no longer recommended for first-line ART regimens and its use is generally avoided. *Tenofovir (TDF)* - While Tenofovir (TDF) can cause **renal toxicity** and **bone mineral density loss** [2], it is generally considered a safer option than stavudine regarding severe metabolic toxicities like lipoatrophy. - TDF is commonly used in first-line ART regimens, often in combination with other drugs. *Zidovudine (AZT)* - **Zidovudine** is associated with side effects such as **bone marrow suppression** (leading to anemia and neutropenia), myopathy, and gastrointestinal upset, but not typically the severe metabolic toxicities seen with stavudine. - It is still used in some ART regimens, particularly for prevention of mother-to-child transmission. *Lamivudine (3TC)* - **Lamivudine** is generally well-tolerated with a favorable side effect profile, primarily mild gastrointestinal symptoms, and is rarely associated with significant metabolic toxicities. - It is a cornerstone drug in many first-line ART regimens due to its efficacy and safety. [Practice more Pharmacology PYQs on OnCourse]

Q: The recommended dose of cotrimoxazole for treatment of pneumonia in a child weighing 16 kg is

Three paediatric tablets twice a day. ***Three paediatric tablets twice a day*** - A paediatric cotrimoxazole tablet contains **20 mg trimethoprim + 100 mg sulfamethoxazole**. - The recommended dose for pneumonia is **4 mg/kg trimethoprim + 20 mg/kg sulfamethoxazole** twice daily. - For a 16 kg child: Required dose = **64 mg trimethoprim + 320 mg sulfamethoxazole** per dose. - Three tablets provide **60 mg trimethoprim + 300 mg sulfamethoxazole**, which is the closest appropriate dose to the calculated requirement. *One paediatric tablet twice a day* - This provides only **20 mg trimethoprim + 100 mg sulfamethoxazole** per dose. - This is **grossly inadequate** for a 16 kg child, providing less than one-third of the required dose. - Such underdosing risks treatment failure and antibiotic resistance. *Two paediatric tablets twice a day* - This provides **40 mg trimethoprim + 200 mg sulfamethoxazole** per dose. - While better than one tablet, this is still **subtherapeutic** for a 16 kg child with pneumonia. - This represents only about 60% of the recommended dose. *Four paediatric tablets twice a day* - This provides **80 mg trimethoprim + 400 mg sulfamethoxazole** per dose. - This is **slightly higher** than required but would risk unnecessary adverse effects. - Three tablets is the more appropriate choice for this weight range. [Practice more Pharmacology PYQs on OnCourse]

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Which of the following statements regarding the composition of common crystalloid solutions is correct ?

Which one of the following statements regarding the composition of common crystalloid solutions is correct ?

Consider the following in respect of Ormeloxifene : 1. It is a research product of Central Drug Research Institute, Lucknow 2. It is a steroidal compound 3. It is a potent antiestrogen with weak estrogenic properties 4. It does not inhibit ovulation Which of the above are correct ?

Which of the following drugs should be avoided in the first-line ART regimens because of its well recognized metabolic toxicities ?

The recommended dose of cotrimoxazole for treatment of pneumonia in a child weighing 16 kg is

Which of the following vaccines are given through the intramuscular route? 1. BCG vaccine 2. Hepatitis B vaccine 3. Pentavalent vaccine 4. Inactivated Polio vaccine

Covaxin is a/an

UPSC-CMS 2021 - Pharmacology UPSC-CMS Practice Questions and MCQs

Question 1: Which of the following statements regarding the composition of common crystalloid solutions is correct ?

A. Normal saline contains 154 mEq/L of Na+ (Correct Answer)
B. Hartmann's solution contains 120 mEq/L of Cl-
C. Hartmann's solution contains 140 mEq/L of Na+
D. Normal saline contains 140 mEq/L of Cl-

Explanation: ***Normal saline contains 154 mEq/L of Na+*** - Normal saline (0.9% NaCl) contains **154 mEq/L of both Na+ and Cl-**, making this statement factually correct. - This makes normal saline **hypernatremic and hyperchloremic** compared to plasma (which has ~140 mEq/L Na+ and ~103 mEq/L Cl-). - Normal saline is useful for correcting **hyponatremia** and for significant volume expansion, but large volumes can cause **hyperchloremic metabolic acidosis**. *Hartmann's solution contains 140 mEq/L of Na+* - Hartmann's solution (Lactated Ringer's) actually contains approximately **130 mEq/L of Na+**, not 140 mEq/L. - The sodium content is designed to be closer to that of **plasma**, making it a more physiologically balanced solution. *Hartmann's solution contains 120 mEq/L of Cl-* - Hartmann's solution contains approximately **109-110 mEq/L of Cl-**, not 120 mEq/L. - This **lower chloride content** compared to normal saline, along with the presence of lactate (28 mEq/L), contributes to a reduced risk of hyperchloremic metabolic acidosis. - The lactate is metabolized to bicarbonate, providing a mild alkalinizing effect. *Normal saline contains 140 mEq/L of Cl-* - Normal saline contains **154 mEq/L of Cl-**, not 140 mEq/L. - Its high chloride content can lead to **hyperchloremic metabolic acidosis** with large-volume administration.

Question 2: Which one of the following statements regarding the composition of common crystalloid solutions is correct ?

A. Hartmann’s solution contains 111 meq/L of Na
B. Normal saline contains 130 meq/L of Cl
C. Normal saline contains 100 meq/L of Na
D. Hartmann’s solution contains 111 meq/L of Cl (Correct Answer)

Explanation: ***Hartmann’s solution contains 111 meq/L of Cl*** - **Hartmann's solution** (Lactated Ringer's) typically contains **111 mmol/L** (or meq/L) of chloride. - Its electrolyte composition aims to mimic plasma more closely than normal saline, with **lower chloride content** to reduce the risk of hyperchloremic acidosis. *Hartmann’s solution contains 111 meq/L of Na* - Hartmann's solution contains approximately **130 meq/L of Na**, not 111 meq/L. - The sodium concentration is higher than 111 meq/L to maintain **isotonicity** and match plasma osmolality. *Normal saline contains 130 meq/L of Cl* - **Normal saline (0.9% NaCl)** contains **154 meq/L of Cl**, which is significantly higher than 130 meq/L. - Its high chloride content can lead to **hyperchloremic metabolic acidosis** if administered in large volumes. *Normal saline contains 100 meq/L of Na* - **Normal saline (0.9% NaCl)** contains **154 meq/L of Na**, not 100 meq/L [1]. - This higher sodium concentration contributes to its **isotonicity** with plasma [1].

Question 3: Consider the following in respect of Ormeloxifene : 1. It is a research product of Central Drug Research Institute, Lucknow 2. It is a steroidal compound 3. It is a potent antiestrogen with weak estrogenic properties 4. It does not inhibit ovulation Which of the above are correct ?

A. 1, 2 and 3
B. 2, 3 and 4
C. 1, 3 and 4 (Correct Answer)
D. 1 and 3 only

Explanation: ***1, 3 and 4*** - Ormeloxifene, also known as **Centchroman**, was developed by the **Central Drug Research Institute (CDRI), Lucknow**, making statement 1 **correct**. - It is a **selective estrogen receptor modulator (SERM)** that acts as a **potent antiestrogen** in the uterus and breast, with **weak estrogenic activity** in other tissues like bone, thus statement 3 is **correct**. - Ormeloxifene has a **unique mechanism** among contraceptives: it **does not inhibit ovulation**. Instead, it works by **preventing implantation** through endometrial changes and altering cervical mucus, making statement 4 **correct**. - Statement 2 is **incorrect** because Ormeloxifene is a **non-steroidal compound**, not a steroidal one. *1, 2 and 3* - This option is incorrect because statement 2, claiming Ormeloxifene is a **steroidal compound**, is false. Ormeloxifene is a **non-steroidal SERM**. - While statements 1 and 3 are correct, the inclusion of incorrect statement 2 makes this option wrong. *1 and 3 only* - While statements 1 and 3 are indeed correct, this option is **incomplete** as it excludes statement 4. - Statement 4 is also correct—Ormeloxifene **does not inhibit ovulation**, which is a key distinguishing feature of this contraceptive. *2, 3 and 4* - This option is incorrect because statement 2 is false—Ormeloxifene is **non-steroidal**, not steroidal. - Although statements 3 and 4 are correct, the inclusion of the false statement 2 makes this entire option incorrect.

Question 4: Which of the following drugs should be avoided in the first-line ART regimens because of its well recognized metabolic toxicities ?

A. Tenofovir (TDF)
B. Stavudine (d4T) (Correct Answer)
C. Zidovudine (AZT)
D. Lamivudine (3TC)

Explanation: ***Stavudine (d4T)*** - **Stavudine** is a **nucleoside reverse transcriptase inhibitor (NRTI)** that is well-known for its significant **metabolic toxicities**, including **lipoatrophy**, peripheral neuropathy, and lactic acidosis [1]. - Due to these severe side effects, it is no longer recommended for first-line ART regimens and its use is generally avoided. *Tenofovir (TDF)* - While Tenofovir (TDF) can cause **renal toxicity** and **bone mineral density loss** [2], it is generally considered a safer option than stavudine regarding severe metabolic toxicities like lipoatrophy. - TDF is commonly used in first-line ART regimens, often in combination with other drugs. *Zidovudine (AZT)* - **Zidovudine** is associated with side effects such as **bone marrow suppression** (leading to anemia and neutropenia), myopathy, and gastrointestinal upset, but not typically the severe metabolic toxicities seen with stavudine. - It is still used in some ART regimens, particularly for prevention of mother-to-child transmission. *Lamivudine (3TC)* - **Lamivudine** is generally well-tolerated with a favorable side effect profile, primarily mild gastrointestinal symptoms, and is rarely associated with significant metabolic toxicities. - It is a cornerstone drug in many first-line ART regimens due to its efficacy and safety.

Question 5: The recommended dose of cotrimoxazole for treatment of pneumonia in a child weighing 16 kg is

A. Four paediatric tablets twice a day
B. Two paediatric tablets twice a day
C. One paediatric tablet twice a day
D. Three paediatric tablets twice a day (Correct Answer)

Explanation: ***Three paediatric tablets twice a day*** - A paediatric cotrimoxazole tablet contains **20 mg trimethoprim + 100 mg sulfamethoxazole**. - The recommended dose for pneumonia is **4 mg/kg trimethoprim + 20 mg/kg sulfamethoxazole** twice daily. - For a 16 kg child: Required dose = **64 mg trimethoprim + 320 mg sulfamethoxazole** per dose. - Three tablets provide **60 mg trimethoprim + 300 mg sulfamethoxazole**, which is the closest appropriate dose to the calculated requirement. *One paediatric tablet twice a day* - This provides only **20 mg trimethoprim + 100 mg sulfamethoxazole** per dose. - This is **grossly inadequate** for a 16 kg child, providing less than one-third of the required dose. - Such underdosing risks treatment failure and antibiotic resistance. *Two paediatric tablets twice a day* - This provides **40 mg trimethoprim + 200 mg sulfamethoxazole** per dose. - While better than one tablet, this is still **subtherapeutic** for a 16 kg child with pneumonia. - This represents only about 60% of the recommended dose. *Four paediatric tablets twice a day* - This provides **80 mg trimethoprim + 400 mg sulfamethoxazole** per dose. - This is **slightly higher** than required but would risk unnecessary adverse effects. - Three tablets is the more appropriate choice for this weight range.

Question 6: Which of the following vaccines are given through the intramuscular route? 1. BCG vaccine 2. Hepatitis B vaccine 3. Pentavalent vaccine 4. Inactivated Polio vaccine

A. 1, 2 and 3
B. 2, 3 and 4 (Correct Answer)
C. 1, 3 and 4
D. 1, 2 and 4

Explanation: ***2, 3 and 4*** - The **Hepatitis B vaccine**, **Pentavalent vaccine** (DPT-Hib-HepB), and **Inactivated Polio Vaccine (IPV)** are all administered via the **intramuscular (IM)** route to ensure proper absorption and immune response. - Intramuscular injection is preferred for these vaccines to deliver antigens directly into muscle tissue, promoting effective antigen-presenting cell uptake. *1, 2 and 3* - This option incorrectly includes the **BCG vaccine**, which is administered intradermally, not intramuscularly. - The **BCG vaccine** creates a localized immune response in the skin, which is crucial for its protective mechanism against tuberculosis. *1, 3 and 4* - This combination is incorrect because it includes the **BCG vaccine**, which is given intradermally. - Administering **BCG intramuscularly** could lead to adverse reactions and reduce vaccine efficacy. *1, 2 and 4* - This option is incorrect as it again includes the **BCG vaccine**, which is administered **intradermally**. - Proper route of administration is critical for vaccine safety and effectiveness, and only **Hepatitis B, Pentavalent, and IPV** are given intramuscularly among the listed choices.

Question 7: Covaxin is a/an

A. Inactivated whole virus vaccine (Correct Answer)
B. Live attenuated vaccine
C. Nucleic acid vaccine
D. Protein subunit vaccine

Explanation: ***Inactivated whole virus vaccine*** - Covaxin is an **inactivated** vaccine, meaning it uses a **killed version of the SARS-CoV-2 virus** that cannot cause disease but can still stimulate an immune response. - This type of vaccine presents the **entire viral structure** to the immune system, leading to a broad immune response against various viral proteins. *Live attenuated vaccine* - A live attenuated vaccine uses a **weakened form of the virus** that can still replicate but does not cause severe disease. - While effective, live attenuated vaccines often carry a small risk of reversion to virulence, which is not the case for Covaxin. *Nucleic acid vaccine* - Nucleic acid vaccines (like mRNA or DNA vaccines) deliver **genetic material** (e.g., mRNA for the spike protein) into host cells to produce viral proteins, triggering an immune response. - Covaxin does not use genetic material directly for antigen production. *Protein subunit vaccine* - Protein subunit vaccines contain only specific, purified viral proteins (e.g., the spike protein) that are highly immunogenic. - Unlike subunit vaccines, Covaxin presents the immune system with the **entire inactivated virus**, not just isolated proteins.