UPSC-CMS 2025 - Pharmacology Practice Questions

Q: A 45 year old farmer came with accidental consumption of a pesticide. He complained of frequent urination and excessive salivation. Which one of the following toxidromes is most likely to be associated with this poisoning?

Cholinergic. ***Cholinergic*** The patient's symptoms of frequent urination and excessive salivation, along with accidental pesticide consumption, are classic signs of **organophosphate poisoning**, which falls under the **cholinergic toxidrome** [1, 2]. This toxidrome is characterized by excessive stimulation of the **cholinergic system**, leading to symptoms memorized by the acronyms **SLUDGE** (Salivation, Lacrimation, Urination, Defecation, Gastrointestinal upset, Emesis) and **DUMBBELS** (Diarrhea, Urination, Miosis, Bradycardia, Bronchorrhea, Emesis, Lacrimation, Salivation) [1]. *Adrenergic* The adrenergic toxidrome is associated with sympathetic overactivity, leading to symptoms like **tachycardia**, **hypertension**, **mydriasis**, agitation, and hyperthermia. These symptoms are opposite to the parasympathetic overactivity observed in this patient. *Hypnotic* The hypnotic toxidrome typically presents with **CNS depression**, including **sedation**, **respiratory depression**, **bradycardia**, and **hypotension**. This toxidrome does not match the patient's symptoms of excessive salivation and frequent urination. *Serotonergic* The serotonergic toxidrome (serotonin syndrome) is characterized by a triad of mental status changes, autonomic hyperactivity (e.g., **tachycardia**, **hypertension**, hyperthermia), and neuromuscular abnormalities (e.g., **hyperreflexia**, clonus). The patient's presentation does not align with these hallmark features.

Q: Consider the following regarding salicylate poisoning : I. Arterial pH of 7.25 , anion gap of 18 mmol / L II. Arterial pH of 7.25 , anion gap of 10 mmol / L III. pCO2 of 20 mm Hg IV. pCO2 of 48 mm Hg Which disturbance is likely to be encountered?

I and III. ***I and III*** - Salicylate poisoning typically presents with a **mixed acid-base disorder** consisting of primary **respiratory alkalosis** and primary **metabolic acidosis with an increased anion gap** [1]. - A pH of 7.25 with an anion gap of 18 mmol/L (normal range 8-12 mmol/L) indicates **metabolic acidosis with an increased anion gap**, while a pCO2 of 20 mmHg (normal range 35-45 mmHg) indicates **respiratory alkalosis** [2]. *II and III* - An anion gap of 10 mmol/L is within the normal range, which is inconsistent with the **metabolic acidosis with increased anion gap** expected in salicylate poisoning [1]. - While pCO2 of 20 mmHg indicates respiratory alkalosis, the normal anion gap makes this combination less likely for salicylate poisoning. *II and IV* - An anion gap of 10 mmol/L is within the normal range, which does not reflect the typical **anion gap metabolic acidosis** seen in salicylate poisoning. - A pCO2 of 48 mmHg indicates respiratory acidosis, which is generally not the primary respiratory disturbance in salicylate poisoning; rather, **respiratory alkalosis** due to direct stimulation of the respiratory center is more characteristic [1]. *I and IV* - While an anion gap of 18 mmol/L is consistent with **anion gap metabolic acidosis**, a pCO2 of 48 mmHg indicates respiratory acidosis. - The classic picture of salicylate poisoning includes **respiratory alkalosis** due to direct stimulation of the respiratory center, not respiratory acidosis [1].

Q: Which one of the following groups of drugs is ineffective against gram positive bacteria?

Monobactams. Monobactams - **Monobactams**, such as **aztreonam**, have a narrow spectrum of activity primarily targeting aerobic **Gram-negative bacteria** [1]. - They lack significant activity against **Gram-positive organisms** and **anaerobes** due to differences in cell wall structure and penicillin-binding proteins (PBPs) [1]. *Glycopeptides* - **Glycopeptides**, like **vancomycin**, are highly effective against a wide range of **Gram-positive bacteria**, including **MRSA** (methicillin-resistant *Staphylococcus aureus*) [3]. - They inhibit cell wall synthesis by binding to the D-Ala-D-Ala precursor, which is crucial for **Gram-positive cell wall integrity**. *Fluoroquinolones* - **Fluoroquinolones** are broad-spectrum antibiotics with activity against both **Gram-positive** and **Gram-negative bacteria** [4]. - While some newer agents (*e.g., levofloxacin, moxifloxacin*) have enhanced **Gram-positive coverage**, older agents (e.g., **ciprofloxacin**) are less potent against Gram-positives [4]. *First generation cephalosporins* - **First-generation cephalosporins** (e.g., **cefazolin**, **cephalexin**) exhibit good activity against many **Gram-positive bacteria**, including **staphylococci** and **streptococci** [2]. - They are commonly used for infections caused by **Gram-positive organisms** and as surgical prophylaxis [2].

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

3 mg/kg. ***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.

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

Valacyclovir 1 g once daily. ***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.

Q: 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 :

I, III and IV. ***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.

Q: 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?

Hyponatremia. ***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.

Question 1

A 45 year old farmer came with accidental consumption of a pesticide. He complained of frequent urination and excessive salivation. Which one of the following toxidromes is most likely to be associated with this poisoning?

Accepted Answer

Cholinergic

Answer

Adrenergic

Answer

Hypnotic

Answer

Serotonergic

Question 2

Consider the following regarding salicylate poisoning :
I. Arterial pH of 7.25 , anion gap of 18 mmol / L
II. Arterial pH of 7.25 , anion gap of 10 mmol / L
III. pCO2 of 20 mm Hg
IV. pCO2 of 48 mm Hg

Which disturbance is likely to be encountered?

Accepted Answer

I and III

Answer

II and III

Answer

II and IV

Answer

I and IV

Question 3

Which one of the following groups of drugs is ineffective against gram positive bacteria?

Accepted Answer

Monobactams

Answer

Glycopeptides

Answer

Fluoroquinolones

Answer

First generation cephalosporins

Question 4

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

Accepted Answer

3 mg/kg

Answer

7 mg/kg

Answer

5 mg/kg

Answer

9 mg/kg

Question 5

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

Accepted Answer

Valacyclovir 1 g once daily

Answer

Acyclovir 400 mg thrice daily

Answer

Acyclovir 400 mg once daily

Answer

Valacyclovir 1 g twice daily

Question 6

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 :

Accepted Answer

I, III and IV

Answer

III and IV only

Answer

I and III only

Answer

II and IV only

Question 7

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?

Accepted Answer

Hyponatremia

Answer

Hypokalemia

Answer

Hypocalcemia

Answer

Hypernatremia

UPSC-CMS 2025 — Pharmacology