UPSC-CMS 2025 — Pharmacology

28 Questions — Page 3 of 3

Q21

Which of the following statements are correct regarding management of hyperkalemia in a child? I. Intravenous calcium (gluconate or chloride) is given to enhance cellular uptake of potassium II. Beta adrenergic agonists (salbutamol or terbutaline) are used to stabilize myocardial cell membrane III. Regular insulin and glucose given intravenously enhance cellular uptake of potassium IV. Sodium polystyrene sulfonate enhances total body potassium elimination Select the answer using the code given below :

Q22

Which of the following statements are correct about oral rotavirus vaccines? I. The storage should be at 2-8°C II. The vaccine should be used within 2 hours of reconstitution or opening III. Past history of intussusception is a contraindication IV. The vaccine can be given if the baby has ongoing diarrhoea Select the answer using the code given below :

Q23

Which of the following medications may be used in a child diagnosed with Attention Deficit Hyperactivity Disorder? I. Carbamazepine II. Methylphenidate III. Atomoxetine IV. Clonazepam Select the correct answer using the code given below :

Q24

The maximum safe dose for Lignocaine (without adrenaline) as a local anaesthetic drug is :

Q25

Daily suppressive therapy for HSV-1 and HSV-2 is :

Q26

Detection of magnesium toxicity in a patient receiving magnesium sulphate is noticed by which of the following? I. Loss of tendon reflexes II. Increased respiratory rate III. Heart block, prolonged PR interval IV. Cardiac arrest Select the correct answer using the code given below :

Q27

The best drug for maintenance therapy of Systemic Lupus Erythematosus (SLE) during pregnancy is :

Q28

A primigravida at 38 weeks pregnancy was put on oxytocin drip in view of slow labour at the rate of 30 mIU/min by the newly appointed registrar. She complains of confusion and starts throwing fits. What electrolyte imbalance is expected to have happened in this case?

UPSC-CMS 2025 - Pharmacology UPSC-CMS Practice Questions and MCQs

Question 21: Which of the following statements are correct regarding management of hyperkalemia in a child? I. Intravenous calcium (gluconate or chloride) is given to enhance cellular uptake of potassium II. Beta adrenergic agonists (salbutamol or terbutaline) are used to stabilize myocardial cell membrane III. Regular insulin and glucose given intravenously enhance cellular uptake of potassium IV. Sodium polystyrene sulfonate enhances total body potassium elimination Select the answer using the code given below :

A. I and II
B. III and IV (Correct Answer)
C. II and III
D. I and IV

Explanation: ***III and IV*** - Intravenous **regular insulin and glucose** work by promoting the intracellular shift of potassium, thereby lowering serum potassium levels. Insulin stimulates the Na+-K+ ATPase pump, moving potassium into cells, and glucose is given to prevent **hypoglycemia**. - **Sodium polystyrene sulfonate (SPS)** is a cation exchange resin that binds potassium in the gastrointestinal tract and promotes its excretion in the stool, thus enhancing **total body potassium elimination**. *I and II* - Intravenous calcium (gluconate or chloride) is given to **stabilize the myocardial cell membrane**, reducing the risk of arrhythmias, not to enhance cellular uptake of potassium. - Beta-adrenergic agonists like **salbutamol** or **terbutaline** promote the intracellular shift of potassium, similar to insulin, but they **do not stabilize the myocardial cell** membrane. *II and III* - Beta-adrenergic agonists **(salbutamol or terbutaline)** promote the cellular uptake of potassium, but they do not stabilize the myocardial cell membrane; that is the role of calcium. - While regular insulin and glucose given intravenously do enhance cellular uptake of potassium, the statement regarding beta-adrenergic agonists is incorrect in its function to stabilize the myocardial cell membrane. *I and IV* - Intravenous calcium (gluconate or chloride) is administered to **protect the heart** from the effects of hyperkalemia by stabilizing the myocardial cell membrane, not to enhance cellular uptake of potassium. - Although sodium polystyrene sulfonate (SPS) correctly enhances total body potassium elimination, the initial statement regarding calcium's mechanism of action is incorrect.

Question 22: Which of the following statements are correct about oral rotavirus vaccines? I. The storage should be at 2-8°C II. The vaccine should be used within 2 hours of reconstitution or opening III. Past history of intussusception is a contraindication IV. The vaccine can be given if the baby has ongoing diarrhoea Select the answer using the code given below :

A. I and II
B. I and III (Correct Answer)
C. II and IV
D. III and IV

Explanation: ***I and III*** * **Oral rotavirus vaccines** require storage at **2-8°C** to maintain potency (cold chain maintenance is essential). * A past history of **intussusception** is an **absolute contraindication** due to increased risk of recurrence. *I and II* * While statement I is correct, statement II is incorrect because oral rotavirus vaccines (Rotarix, RotaTeq) are **ready-to-use liquid formulations** that do **not require reconstitution**. Once the container is opened, the vaccine should be **administered immediately** during the same vaccination visit, not stored for 2 hours. *II and IV* * Statement II is incorrect as oral rotavirus vaccines are **ready-to-use** and should be **administered immediately** after opening, without any reconstitution. * Statement IV is incorrect because the vaccine **should be postponed** if the baby has ongoing **moderate to severe diarrhoea** or vomiting, as this may affect vaccine absorption and effectiveness. Mild diarrhea is not a contraindication, but significant gastroenteritis warrants deferral. *III and IV* * While statement III is correct, statement IV is incorrect because ongoing **moderate to severe diarrhoea** is a reason to **postpone** administration of the rotavirus vaccine until the child recovers.

Question 23: Which of the following medications may be used in a child diagnosed with Attention Deficit Hyperactivity Disorder? I. Carbamazepine II. Methylphenidate III. Atomoxetine IV. Clonazepam Select the correct answer using the code given below :

A. I and III
B. I and IV
C. II and III (Correct Answer)
D. II and IV

Explanation: ***II and III*** - **Methylphenidate** is a first-line **CNS stimulant** that increases dopamine and norepinephrine in the prefrontal cortex, improving attention and reducing hyperactivity/impulsivity - **Atomoxetine** is a **selective norepinephrine reuptake inhibitor (SNRI)**, FDA-approved as a non-stimulant alternative for ADHD management - Both medications are **evidence-based treatments** for ADHD in children with proven efficacy in controlled trials *I and III* - **Carbamazepine** is an anticonvulsant used for epilepsy and bipolar disorder, **not indicated for ADHD** - While Atomoxetine is correct, pairing it with Carbamazepine makes this option incorrect *I and IV* - **Carbamazepine** has no role in ADHD management - **Clonazepam** is a benzodiazepine used for anxiety and seizures, **contraindicated in ADHD** as it causes sedation and may worsen attention deficits *II and IV* - While Methylphenidate is a core ADHD medication, **Clonazepam is inappropriate** for ADHD treatment - Benzodiazepines can impair cognitive function and exacerbate attention problems in ADHD patients

Question 24: The maximum safe dose for Lignocaine (without adrenaline) as a local anaesthetic drug is :

A. 7 mg/kg
B. 5 mg/kg
C. 9 mg/kg
D. 3 mg/kg (Correct Answer)

Explanation: ***3 mg/kg*** - The maximum safe dose for **plain lignocaine** (without adrenaline) is **3 mg/kg**. - Exceeding this limit increases the risk of **systemic toxicity**, particularly central nervous system and cardiovascular effects. *7 mg/kg* - This dosage refers to the maximum safe dose of **lignocaine when combined with adrenaline**. - **Adrenaline causes vasoconstriction**, which delays systemic absorption of lignocaine, allowing for a higher total dose. *5 mg/kg* - This is also within the range of the maximum safe dose for **lignocaine with adrenaline**, though it is sometimes quoted as the upper limit for **plain lignocaine** by some references. - However, for plain lignocaine, **3 mg/kg is the more widely accepted and safer standard**. *9 mg/kg* - This dose is **significantly higher** than the recommended maximum for both plain and adrenaline-containing lignocaine. - Administering 9 mg/kg would carry a **very high risk of severe systemic toxicity**, including convulsions and cardiac arrest.

Question 25: Daily suppressive therapy for HSV-1 and HSV-2 is :

A. Acyclovir 400 mg thrice daily
B. Valacyclovir 1 g once daily (Correct Answer)
C. Acyclovir 400 mg once daily
D. Valacyclovir 1 g twice daily

Explanation: ***Valacyclovir 1 g once daily*** - **Valacyclovir 1 g once daily** is an effective and commonly prescribed regimen for daily suppressive therapy of HSV-1 and HSV-2 due to its good bioavailability and convenient once-daily dosing. - This dosage is particularly effective in reducing the frequency of outbreaks and the risk of transmission. *Acyclovir 400 mg thrice daily* - While **acyclovir** is an effective antiviral for HSV, the standard dose for suppressive therapy is typically **400 mg twice daily** (not thrice daily) to maintain adequate antiviral levels. - A thrice-daily regimen might be used for acute outbreaks but is generally not preferred for long-term daily suppression due to adherence challenges. *Acyclovir 400 mg once daily* - **Acyclovir 400 mg once daily** is generally considered insufficient for effective daily suppressive therapy for HSV infections. - This low frequency of dosing would likely not maintain adequate antiviral concentrations to consistently prevent outbreaks. *Valacyclovir 1 g twice daily* - **Valacyclovir 1 g twice daily** is often used for the treatment of acute HSV outbreaks (e.g., genital herpes episodes) or for severe cases of suppression, but it is not the standard daily suppressive dose. - For routine daily suppressive therapy, a 1g once-daily dose is usually sufficient and preferred for convenience and patient adherence.

Question 26: Detection of magnesium toxicity in a patient receiving magnesium sulphate is noticed by which of the following? I. Loss of tendon reflexes II. Increased respiratory rate III. Heart block, prolonged PR interval IV. Cardiac arrest Select the correct answer using the code given below :

A. III and IV only
B. I and III only
C. I, III and IV (Correct Answer)
D. II and IV only

Explanation: ***I, III and IV*** - **Loss of tendon reflexes** is an early sign of magnesium toxicity, typically occurring at serum magnesium levels between **4-6 mEq/L**. - **Heart block** and a **prolonged PR interval** are cardiac manifestations of magnesium toxicity, indicating impaired electrical conduction in the heart. **Cardiac arrest** represents the most severe cardiac complication, usually occurring with very high magnesium levels (**>15 mEq/L**). *III and IV only* - This option correctly identifies **heart block** (prolonged PR interval) and **cardiac arrest** as signs of magnesium toxicity. - However, it **omits the loss of tendon reflexes**, which is a crucial and often earlier indicator of toxicity. *I and III only* - This option correctly includes **loss of tendon reflexes** and **heart block** (prolonged PR interval) as signs of magnesium toxicity. - It **fails to include cardiac arrest**, which is a severe and critical consequence of profound magnesium toxicity. *II and IV only* - **Increased respiratory rate** is generally **not a sign of magnesium toxicity**; rather, magnesium toxicity can lead to **respiratory depression** or arrest. - While **cardiac arrest** is a correct sign, the inclusion of increased respiratory rate makes this option inaccurate.

Question 27: The best drug for maintenance therapy of Systemic Lupus Erythematosus (SLE) during pregnancy is :

A. Tacrolimus
B. Hydroxychloroquine (Correct Answer)
C. Progestins
D. Sulfasalazine

Explanation: ***Hydroxychloroquine*** - **Hydroxychloroquine** is the cornerstone of SLE treatment, including during pregnancy, due to its efficacy in preventing flares and its established safety profile for both mother and fetus. - Continuation of **hydroxychloroquine** throughout pregnancy is recommended to reduce the risk of disease activity, which can lead to adverse maternal and fetal outcomes. *Tacrolimus* - **Tacrolimus** is an immunosuppressant typically reserved for patients with severe organ-threatening lupus, such as lupus nephritis, especially when other treatments fail or are contraindicated. - While it can be used in pregnancy under close monitoring, it is not considered the first-line or best drug for routine maintenance therapy due to potential risks and the availability of generally safer options. *Progestins* - **Progestins** are hormones primarily used in contraception or hormone replacement therapy and have no direct role in the treatment or maintenance of systemic lupus erythematosus. - They do not possess immunomodulatory properties essential for managing SLE disease activity. *Sulfasalazine* - **Sulfasalazine** is an anti-inflammatory and immunomodulatory drug primarily used for inflammatory bowel disease and rheumatoid arthritis, and sometimes for psoriatic arthritis. - It is not a standard treatment for **Systemic Lupus Erythematosus (SLE)** and is less effective for systemic manifestations of lupus.

Question 28: A primigravida at 38 weeks pregnancy was put on oxytocin drip in view of slow labour at the rate of 30 mIU/min by the newly appointed registrar. She complains of confusion and starts throwing fits. What electrolyte imbalance is expected to have happened in this case?

A. Hypokalemia
B. Hyponatremia (Correct Answer)
C. Hypocalcemia
D. Hypernatremia

Explanation: ***Hyponatremia*** - **Oxytocin** has an antidiuretic hormone (ADH)-like effect, leading to **water retention** and dilutional hyponatremia, especially when administered in large doses or with hypotonic solutions [1]. - Symptoms like **confusion** and **seizures (fits)** are classic signs of neurological impairment due to severe hyponatremia. *Hypokalemia* - While electrolyte imbalances can occur with oxytocin, **hypokalemia** is not typically associated with oxytocin's ADH-like actions or its direct effects on renal tubules. - Symptoms related to hypokalemia usually involve **muscle weakness** and cardiac arrhythmias, which are not the primary features here. *Hypocalcemia* - **Hypocalcemia** is more commonly associated with conditions like parathyroid dysfunction or vitamin D deficiency, not directly with oxytocin administration. - Symptoms would typically include **tetany**, muscle cramps, and paresthesias, not primarily confusion and seizures in this context. *Hypernatremia* - **Hypernatremia** would involve excess sodium or severe dehydration, which is contrary to the fluid retention effect of oxytocin and unlikely to cause seizures in this context. - Elevated sodium levels would typically present with symptoms of extreme thirst, lethargy, and dry mucous membranes.