Gastroenteritis: pharmacological management MCQs With Answer

Gastroenteritis: pharmacological management MCQs With Answer

This quiz is designed for M.Pharm students studying Pharmacotherapeutics II (MPP 202T) to deepen understanding of evidence-based pharmacological strategies for gastroenteritis. It emphasizes mechanisms of action, drug selection for specific pathogens and syndromes (traveller’s diarrhea, cholera, giardiasis, cryptosporidiosis, C. difficile), indications and contraindications for antidiarrheal and antisecretory agents, role of rehydration and zinc, probiotic choices, and stewardship principles for antibiotic use. Questions combine clinical scenarios and pharmacology to test decision-making, dosing principles, adverse effects and special-population considerations. Use this to review key concepts and prepare for higher-level assessments and practical therapeutic choices in infectious and noninfectious diarrheal disease management.

Q1. Which composition best describes the WHO reduced-osmolarity oral rehydration solution (ORS) recommended for most cases of acute watery diarrhea?

• Na ~75 mmol/L, glucose ~75 mmol/L, total osmolarity ~245 mOsm/L
• Na ~90 mmol/L, glucose ~111 mmol/L, total osmolarity ~310 mOsm/L
• Na ~50 mmol/L, glucose ~50 mmol/L, total osmolarity ~160 mOsm/L
• Na ~120 mmol/L, glucose ~120 mmol/L, total osmolarity ~360 mOsm/L

Correct Answer: Na ~75 mmol/L, glucose ~75 mmol/L, total osmolarity ~245 mOsm/L

Q2. In a patient with severe dehydration from cholera, which initial fluid therapy is recommended to rapidly restore intravascular volume?

• Oral rehydration solution only until urine output improves
• Isotonic crystalloid intravenous therapy (Ringer’s lactate or normal saline)
• Hypotonic saline to correct hypernatremia rapidly
• Colloid solutions (albumin) as first-line resuscitation

Correct Answer: Isotonic crystalloid intravenous therapy (Ringer’s lactate or normal saline)

Q3. Which statement best describes the mechanism and a key safety consideration of loperamide in acute diarrheal illness?

• Loperamide is a peripheral μ-opioid receptor agonist that reduces gut motility; it is contraindicated in bloody diarrhea or febrile invasive infections due to risk of toxic megacolon
• Loperamide is a serotonin antagonist that increases intestinal secretion; it is safe in all forms of infectious diarrhea
• Loperamide is a systemic opioid that crosses the blood–brain barrier and is first-line for C. difficile
• Loperamide acts as a chloride channel blocker and is indicated with high fever and bloody stools

Correct Answer: Loperamide is a peripheral μ-opioid receptor agonist that reduces gut motility; it is contraindicated in bloody diarrhea or febrile invasive infections due to risk of toxic megacolon

Q4. Rifaximin is most appropriately used empirically for which diarrheal syndrome?

• Non-invasive traveller’s diarrhea caused by enterotoxigenic E. coli (ETEC)
• Severe bloody colitis due to Shigella with high fever
• C. difficile infection with pseudomembranous colitis
• Invasive Salmonella typhi systemic infection

Correct Answer: Non-invasive traveller’s diarrhea caused by enterotoxigenic E. coli (ETEC)

Q5. What is the recommended single-dose antibiotic for adult cholera in otherwise healthy nonpregnant adults according to conventional guidelines?

• Single-dose doxycycline 300 mg
• Azithromycin 250 mg once daily for 7 days
• Ciprofloxacin 500 mg single dose
• Metronidazole 500 mg three times daily for 5 days

Correct Answer: Single-dose doxycycline 300 mg

Q6. For initial management of non-severe Clostridioides difficile infection, which agent is recommended as first-line therapy in current guidelines?

• Oral vancomycin 125 mg four times daily for 10 days
• Intravenous metronidazole 500 mg every 8 hours
• Oral rifaximin 200 mg three times daily for 3 days
• Oral loperamide to reduce stool frequency

Correct Answer: Oral vancomycin 125 mg four times daily for 10 days

Q7. Racecadotril reduces diarrheal volume by which primary pharmacological mechanism?

• Inhibition of enkephalinase (neutral endopeptidase) leading to reduced intestinal secretion
• Direct blockade of intestinal chloride channels (CFTR inhibition)
• Activation of opioid receptors in the central nervous system to decrease motility
• Antimicrobial action against Gram-negative enteric pathogens

Correct Answer: Inhibition of enkephalinase (neutral endopeptidase) leading to reduced intestinal secretion

Q8. What is the recommended zinc supplementation dose for children with acute diarrhoea in WHO guidelines?

• 20 mg elemental zinc daily for 10–14 days (10 mg daily for infants <6 months)
• 100 mg daily for 3 days only
• No zinc supplementation is recommended
• 2 mg daily for 14 days

Correct Answer: 20 mg elemental zinc daily for 10–14 days (10 mg daily for infants <6 months)

Q9. Which statement best characterizes bismuth subsalicylate in traveler’s diarrhea?

• Bismuth subsalicylate has antisecretory and mild antimicrobial effects and can reduce incidence/severity of traveler’s diarrhea; avoid in salicylate allergy
• Bismuth subsalicylate is a systemic antibiotic that eradicates Salmonella from the blood
• Bismuth subsalicylate is contraindicated in all adults due to high toxicity
• Bismuth subsalicylate acts as a prokinetic agent increasing transit time

Correct Answer: Bismuth subsalicylate has antisecretory and mild antimicrobial effects and can reduce incidence/severity of traveler’s diarrhea; avoid in salicylate allergy

Q10. Which probiotic organisms have the strongest evidence to reduce duration or prevent antibiotic-associated diarrhoea?

• Lactobacillus rhamnosus GG and Saccharomyces boulardii
• Escherichia coli Nissle only
• Clostridium difficile strain probiotics
• Serratia marcescens preparations

Correct Answer: Lactobacillus rhamnosus GG and Saccharomyces boulardii

Q11. Nitazoxanide is primarily indicated for which of the following infectious diarrheas?

• Cryptosporidiosis and giardiasis (effective oral antiparasitic activity)
• Non-invasive ETEC traveller’s diarrhea as first-line antibiotic
• C. difficile infection as the preferred agent
• Systemic Salmonella typhi bacteremia

Correct Answer: Cryptosporidiosis and giardiasis (effective oral antiparasitic activity)

Q12. For single-dose therapy of giardiasis in adults, which agent and regimen is commonly preferred due to convenience and efficacy?

• Tinidazole 2 g single dose
• Metronidazole 250 mg once daily for 1 day
• Rifaximin 200 mg single dose
• Bismuth subsalicylate 524 mg single dose

Correct Answer: Tinidazole 2 g single dose

Q13. In acute diarrhoea, which clinical scenario most strongly indicates empirical antibiotic therapy?

• Bloody stools, high fever, and systemic toxicity suggesting invasive bacterial enteritis
• Mild watery diarrhoea without fever in a previously healthy adult
• Viral gastroenteritis confirmed by rapid antigen test
• Isolated nausea and vomiting without diarrhea

Correct Answer: Bloody stools, high fever, and systemic toxicity suggesting invasive bacterial enteritis

Q14. Octreotide is best reserved for which diarrhoeal conditions?

• Severe secretory diarrheas (e.g., VIPoma, refractory chemotherapy-induced or bile salt diarrhoea) not responsive to standard therapy
• Acute uncomplicated traveller’s diarrhea as first-line therapy
• Mild viral gastroenteritis to shorten duration
• Prophylaxis against C. difficile recurrence

Correct Answer: Severe secretory diarrheas (e.g., VIPoma, refractory chemotherapy-induced or bile salt diarrhoea) not responsive to standard therapy

Q15. Which of the following is true regarding use of antimotility agents in C. difficile infection?

• Antimotility agents (e.g., loperamide) are generally contraindicated during active C. difficile infection because they may worsen toxin-mediated disease
• Antimotility agents are first-line adjuncts to vancomycin in severe C. difficile
• Antimotility agents eradicate C. difficile spores from the gut
• Antimotility agents are required to prevent transmission of C. difficile

Correct Answer: Antimotility agents (e.g., loperamide) are generally contraindicated during active C. difficile infection because they may worsen toxin-mediated disease

Q16. What is the principal advantage of fidaxomicin over oral vancomycin in treatment of C. difficile?

• Lower rates of recurrence with comparable cure rates for certain strains
• Fidaxomicin is given intravenously and achieves higher blood levels
• Fidaxomicin is effective as a single-dose therapy
• Fidaxomicin is a broad-spectrum systemic antibiotic covering enteric Gram-negatives

Correct Answer: Lower rates of recurrence with comparable cure rates for certain strains

Q17. In regions with high fluoroquinolone resistance, which oral antibiotic is preferred for empiric treatment of moderate-to-severe traveler’s diarrhea?

• Azithromycin (single-dose or short-course therapy)
• Ciprofloxacin single high dose regardless of resistance patterns
• Metronidazole monotherapy for all traveler’s diarrhea
• Tetracycline topical therapy

Correct Answer: Azithromycin (single-dose or short-course therapy)

Q18. Which statement about adsorbents (e.g., kaolin-pectin) in acute diarrhoea is most accurate?

• Adsorbents may reduce stool liquidity but have limited evidence for major clinical benefit and are not a substitute for rehydration and targeted therapy
• Adsorbents have strong bactericidal activity against invasive enteric pathogens and are first-line antibiotics
• Adsorbents are recommended for C. difficile as monotherapy
• Adsorbents are recommended instead of ORS for rehydration

Correct Answer: Adsorbents may reduce stool liquidity but have limited evidence for major clinical benefit and are not a substitute for rehydration and targeted therapy

Q19. For rotavirus gastroenteritis in children, which pharmacologic intervention has proven clinical benefit?

• Oral rehydration therapy and zinc supplementation; no specific antiviral therapy is routinely recommended
• Ribavirin oral therapy for 7 days is standard of care
• Routine antibiotics shorten disease duration and are indicated
• High-dose intravenous immunoglobulin is first-line outpatient therapy

Correct Answer: Oral rehydration therapy and zinc supplementation; no specific antiviral therapy is routinely recommended

Q20. Which preventive measure has evidence for reducing the incidence of traveler’s diarrhea when taken prophylactically during travel?

• Regular dosing of bismuth subsalicylate (e.g., two tablets up to four times daily) during travel
• Daily loperamide prophylaxis for all travelers regardless of destination
• Prophylactic ciprofloxacin for all travelers to low-risk areas
• Routine rifaximin prophylaxis for more than 6 months of travel

Correct Answer: Regular dosing of bismuth subsalicylate (e.g., two tablets up to four times daily) during travel

Download