05 Comparing Drugs for Diarrhea and Constipation

Question 1

When is intravenous rehydration recommended for diarrhea?

Answer 1

When fluid loss is severe, exceeding 10% of body weight.

Question 2

What is the composition of recommended IV fluids for severe diarrhea?

Answer 2

NaCl: 85 mM (5g/L)
KCl: 13 mM (1g/L)
5% glucose solution
NaHCO3: 48 mM (48g/L)

Question 3

What alternative IV fluid does WHO recommend for diarrhea?

Answer 3

Ringer lactate (Na+ 130, Cl- 109, K+ 4, lactate 28 mM).

Question 4

What are the advantages of the new WHO-ORS formula for oral rehydration?

Answer 4

1 .Reduces stool volume by 20% and vomiting by 30%.
2. Corrects acidosis with added bases (bicarbonate, citrate, lactate).
3. Promotes independent Na+ and water absorption.

Question 5

How is ORT administered for diarrhea treatment?

Answer 5

ORS is given at 1/2 to 1-hour intervals, aiming to restore hydration in 6 hours. The pediatric dose is 5 ml/kg/hr.

Question 6

What are some non-diarrheal uses of ORT?

Answer 6

1. Post-surgical, burn, and trauma hydration.
2. Heat stroke.
3. Transitioning from IV to enteral feeding.

Question 7

What is the role of Super ORS in diarrhea management?

Answer 7

It uses amino acids (e.g., alanine, glycine) to enhance sodium cotransport, but its efficacy is marginal.

Question 8

When are antimicrobials used for diarrhea?

Answer 8

1. Severe infectious diarrhea.
2. Specific conditions like traveler’s diarrhea, cholera, C. difficile, amoebiasis, and giardiasis.

Question 9

Name two antimicrobials used for cholera.

Answer 9

Tetracyclines and ciprofloxacin.

Question 10

What is the mechanism of action for antimotility drugs in diarrhea?

Answer 10

1. Increase small bowel tone and reduce propulsive movements.
2. Decrease intestinal secretions and increase absorption.
3. Increase resistance to luminal transit.

Question 11

Name a commonly used antimotility drug and its receptor target.

Answer 11

Loperamide, which acts as a μ receptor agonist.

Question 12

What are bulk laxatives, and how do they work for constipation?

Answer 12

Bulk laxatives absorb water to form a gel-like mass, increasing bulk and promoting peristalsis.

Question 13

Provide an example of a bulk laxative.

Answer 13

Ispagula husk, which contains natural mucilage.

Question 14

How do osmotic laxatives relieve constipation?

Answer 14

They retain water in the intestine, increasing bulk and peristalsis, resulting in softer stools.

Question 15

What is the primary use of lactulose as a laxative?

Answer 15

Acts as an osmotic purgative, fermented to acids that lower blood ammonia levels in hepatic coma.

Question 16

How is polyethylene glycol (PEG) used for bowel preparation?

Answer 16

Administered as a balanced isotonic solution, ingested rapidly (3-4 liters) for bowel cleansing.

Question 17

Name two peripherally-acting opioid antagonists for opioid-induced constipation.

Answer 17

Methylnaltrexone bromide and naloxegol.

Question 18

What is a side effect of prolonged use of stimulant laxatives like bisacodyl?

Answer 18

Prolonged use (over 10 days) can cause proctitis and rectal burning.