Gastrointestinal Question And Answers

Gastrointestinal Important Notes

1. Drugs used in peptic ulcer

2. Cimetidine

• Inhibits several cytochrome P-450 isoenzyme
• Reduces hepatic blood flow
• Inhibits the metabolism of many drugs

3. Kaolin

• It is a hydrated aluminum silicate
• Used in the treatment of diarrhea
• Act as an absorbent of bacteria and bacterial toxin

4. Antacids

• They are salts of magnesium, calcium, and aluminum
• Produces laxatives or constipating effects

5. H2 receptor antagonist

• They are ranitidine, cimetidine, famotidine
• Inhibit gastric secretion
• Adverse effects
  • Gynaecomastia
  • Impotence

6. Omeprazole

• Inhibits proton pump
• It is powerful
• Totally abolishes HC1 secretion

7. Drugs used in motion sickness

• Scopolamines
• Antihistamines

Gastrointestinal Long Essays

Question 1. What is an antacid? Classify with suitable examples. Mention the merits and demerits of NaHC03 as an antacid.
Answer:

Antacids

• Antacids are basic substances that neutralize gastric acid and raise the pH of gastric contents

Antacids Classification

1. Systemic antacids

• Sodium bicarbonate
• Sodium citrate

2. Non-systemic antacids

• Magnesium hydroxide
• Magnesium trisilicate
• Aluminum hydroxide gel
• Magaldrate

Sodium Bicarbonate as Antacids:

Sodium Bicarbonate Merits:

• Water soluble
• Acts instantly
• Potent neutralizer
• Raises pH above 7

Sodium Bicarbonate Demerits:

• Absorbed systemically
• Acid rebounds occur
• Increases sodium load

Gastrointestinal Short Essays

Question 1. Classify drugs used in peptic ulcer
Answer:

Peptic ulcer occurs in that part of the gastrointestinal tract which is exposed to gastric acid and pepsin. Produces carbon dioxide in the stomach

Classify drugs used in peptic ulcer  Classification:

• Drugs used in the treatment of peptic ulcer are:

1. Reduction of gastric acid secretion

• H2 Antihistamines
  • Cimetidine, Ranitidine, Famotidine, Roxatidine, Loxatidine
• Proton pump inhibitors
  • Omeprazole, Lansoprazole, Pantoprazole, Rabepra- zole
• Anticholinergic
  • Pirenzepine, Propantheline
• Prostaglandin analogs
  • Misoprostol

2. Neutralization of gastric acid- antacids

• Systemic antacids
  • Sodium bicarbonate
  • Sodium citrate
• Nonsystemic antacids
  • Magnesium hydroxide
  • Magnesium trisilicate
  • Aluminum hydroxide gel
  • Magaldrate

3. Ulcer protective

• Sucralfate, colloidal bismuth substrate

4. Anti-H pylori drugs

• Amoxicillin, metronidazole, Clarithromycin

Question 2. Antihistaminic drugs used in peptic ulcer.
(or)
H2 blockers
Answer:

• Antihistaminic drugs or H2 blockers are:
  • Cimetidine, Ranitidine, Famotidine, Roxatidine, Loxatidine
• They are highly effective drugs

H2 blockers  Actions:

1. H2 blockade-Causes:

• Blockade of histamine-induced gastric secretion
• Cardiac stimulation
• Uterine relaxation
• Bronchial relaxation
• Fall in BP

2. Gastric secretion

• Inhibition of gastric secretion
• Prevention of gastric ulceration occurring due to stress and drugs

H2 blockers  Uses:

• Duodenal ulcer- provides rapid and marked pain relief
• Gastric ulcer- Heal NSAID-associated ulcers
• Stress ulcers- Occurring in situations like severe burns, trauma, prolonged surgery, etc.
• Zollinger-Elison syndrome
• Gastroesophageal reflux disease
• Prophylaxis of aspiration pneumonia

H2 blockers  Adverse Effects:

• Headache, dizziness, bowel upset, dry mouth, rashes
• CNS effects- confusion, restlessness, hallucinations
• Antiandrogenic effect of cimetidine

Question 3. Ranitidine
Answer:

• Ranitidine is an H2 receptor blocker

Read And Learn More: Pharmacology Question and Answers

Ranitidine  Uses:

• Duodenal ulcer- provides rapid and marked pain relief
• Gastric ulcer- Heal NSAID-associated ulcers
• Stress ulcers- Occurring in situations like severe burns, trauma, prolonged surgery, etc.
• Zollinger-Elison syndrome
• Gastroesophageal reflux disease
• Prophylaxis of aspiration pneumonia

Ranitidine  Advantages:

• More potent
• Longer-acting
• Has no antiandrogenic effects
• No CNS effects as it does not cross BBB
• Does not inhibit microsomal enzymes
• Has mild side effects

Question 4. Antacids
Answer:

Antacids:

• Antacids are basic substances that neutralize gastric acid and raise the pH of gastric contents.

Antacids Classification:

1. Systemic antacids

• Sodium bicarbonate
• Sodium citrate

2. Nonsystemic antacids

• Magnesium hydroxide
• Magnesium trisilicate
• Aluminum hydroxide gel
• Magaldrate

Antacids Uses:

• For intercurrent pain relief and acidity
• Nonulcer dyspepsia
• Minor episodes of heartburn
• Reflux esophagitis

Antacids Disadvantages:

• Needed in large and frequent dose
• Inconvenient
• Can cause acid rebound and bowel upset
• Poor patient acceptability

Question 5. Compare promethazine and Ranitidine
Answer:

Question 6. Emetics
Answer:

Emetics are drugs that produce vomiting

Emetics  Mechanism:

Emetics  Uses:

• To induce vomiting when noxious substances are ingested

Emetics  Drugs Used:

• Mustard powder-1 teaspoon with water
• Hypertonic salt solution
• Apomorphine- SC/ IM
• Ipecacuanha-15-20 ml

Emetics  Contraindications:

• Corrosive poisoning
• CNS stimulant drug poisoning
• Kerosene or petroleum poisoning
• In unconscious patients

Question 7. Metoclopramide
Answer:

• Metoclopramide is widely used as antiemetic

Metoclopramide  Actions:

• Increases gastric peristalsis
• Relaxes the pylorus and the first part of the duodenum
• Speeds up gastric emptying

Metoclopramide  Mechanism of Action:

• Blocks D₂ dopamine receptors in the CTZ
• Enhances acetylcholine release from the cholinergic neurons in the gut

Metoclopramide  Uses:

• Antiemetic- in postoperative, drug-induced, disease-associated vomiting
• Gastrokinetic- To accelerate gastric emptying
  • Before induction of general anesthesia
  • To assist the passage of the tube into the duodenum
  • To relieve diabetes-associated gastric stasis
• Dyspepsia
• Gastroesophageal reflux disease- provides symptomatic relief

Metoclopramide  Adverse Effects:

• Sedation
• Dizziness
• Diarrhea
• Muscle dystonia
• Long-term use causes:
  • Parkinsonism
  • Galactorrhoea
  • Gynaecomastia

Question 8. Prokinetic Agents
Answer:

Drugs that promote gastrointestinal and speedy gastric emptying are called prokinetic agents.

They are as follows:

Question 9. Rationale of using domperiodone as antiemetics
(or)
Domperidone is preferred over Metaclopra- mide in vomiting
Answer:

• Domperidone is D₂ antagonist
• Its action is not blocked by atropine
• It crosses the blood-brain barrier poorly
• It does not have extrapyramidal side effects
• Side effects of Domperidone are much less than that with Metadopramide
• It includes only dry mouth, loose stools, headache, rashes, galactorrhoea
• Thus it is preferred over Metadopramide as an Antiemetic

Question 10. Mention two antiemetics.
Answer:

Antiemetics:

1. Metoclopramide
2. Domperidone

Question 11. Drugs used as purgatives
Answer:

• Purgatives are drugs that promote defecation
• They are also called laxatives

Purgatives  Classification:

1. Bulk-forming

• Dietary fiber- Bran, plantago seeds, is Paula, methylcellulose

2. Stool softener

• Docusates, liquid paraffin

3. Stimulant Purgatives

• Diphenylmethanes
  • Phenolphthalein, bisacodyl
• Anthraquinones
  • Senna, cascara sagrada
• 5-HT₄ agonist
  • Tegaserod

4. Osmotic Purgatives

• Magnesium salts- sulfate, hydroxide
• Sodium salts- sulfate, phosphate
• Sodium potassium tartrate

Purgatives Mechanisms:

Increases water content of feces by

1. Osmotic action

3. Secondary effects

• Increases propulsive activity
• Decreases time for absorption

Purgatives Uses:

• In functional constipation
• In bedridden patients
• To avoid straining at stools
• Preparation of bowel for surgery, colonoscopy, abdominal X-ray
• After certain antihelminthic

Question 12. ORS
Answer:

• Oral rehydration solution is used in patients with diarrhea to replenish the lost water

ORS  Composition:

• NaCl -3.5 g
• KC1 -1.5 g
• Trisodium citrate -2.9 g
• Glucose -20 g
• Water-1 liter

ORS  Uses:

• To replace fluids and salts lost from the body during diarrhea
• To restore and maintain hydration
• Maintain electrolyte and pH balance
• Maintain hydration in patients postsurgically after burns, trauma, and in heat stroke

Question 13. The rationale for using loperamide in diarrhea
Answer:

• Loperamide is an opiate analog
• It is the potent constipating agent
• It has a poor water solubility
• Entry of it into the brain is negligible
• So it has no CNS effects occur
• It also inhibits GIT secretions
• Abdominal cramps and rashes are common adverse effects.
• Thus it is preferred for diarrhea

Question 14. PPIs (proton pump inhibitors)
Answer:

• Proton pump inhibitors are the most efficient inhibitors of the gastric acid secretion
• They are given as enteric-coated granules to avoid degeneration by the acid in the stomach
• They are:
  • Omeprazole
  • Lansoprazole
  • Pantoprazole
  • Rabeprazole
  • Dexrabeprazole
  • Esomeprazole

PPIs (proton pump inhibitors)  Mechanism of Action:

• Proton pump inhibitors get accumulated in the parietal cells

PPIs (proton pump inhibitors)  Uses:

1. Peptic ulcers

• Given for 4-8 weeks
• Ulcers heal fast
• Relief of pain is rapid and excellent

2. Gastroesophageal reflux disease

• Produces rapid symptomatic relief
• It is more effective than H2 blockers

3. Use in H. pylori treatment regimen

4. Zollinger- Ellison syndrome

PPIs (proton pump inhibitors)  Adverse Effects:

• Adverse effects are minimal
• They occur rarely
• It includes:
  • Nausea
  • Loose stools
  • Headache
  • Abdominal pain
  • Muscle and joint pain
  • Dizziness
  • Rashes
  • Leucopenia
  • Hepatic dysfunction

Gastrointestinal Short Question and Answers

Question 1. H2 antagonist
Answer:

• Antihistaminic drugs or H2 blockers are:
  • Cimetidine, Ranitidine, Famotidine, Roxatidine, Loxatidine
• They are highly effective drugs

Question 2. Cimetidine
Answer:

• Cimetidine is an H2 blocker
• It was the first H2 blocker to be introduced

Cimetidine  Uses:

• Duodenal ulcer- provides rapid and marked pain relief
• Gastric ulcer- Heal NSAID-associated ulcers
• Stress ulcers- Occurring in situations like severe burns, trauma, prolonged surgery, etc.
• Zollinger-Elison syndrome
• Gastroesophageal reflux disease
• Prophylaxis of aspiration pneumonia

Question 3. Antacids
Answer:

Antacids are basic substances that neutralize gastric acid and raise the pH of gastric contents.

Antacids Classification:

1. Systemic antacids

• Sodium bicarbonate
• Sodium citrate

2. Nonsystemic antacids

• Magnesium hydroxide
• Magnesium trisilicate
• Aluminum hydroxide gel
• Magaldrate

Question 4. Sucralfate
Answer:

Sucralfate is an ulcer protective agent

Sucralfate Mechanism:

• In an acidic medium, Sucralfate polymerizes to form a sticky, viscid gel
• This adheres firmly to the base of the ulcer
• Act as a physical barrier preventing acid, pepsin, and bile from coming in contact with ulcer base
• Stimulates prostaglandin secretion and promotes healing

Sucralfate Uses:

• Duodenal ulcer
• Gastric ulcer

Sucralfate Adverse Effects:

• Constipation
• Dry mouth

Question 5. Carbenoxolone sodium
Answer:

• Carbenoxolone sodium is a steroid-like compound
• It is obtained from glycyrrhizic acid

Carbenoxolone sodium Mechanism of Action:

• It alters the composition of mucous
• Makes it more viscid
• Gets adheres to the gastric mucosa
• Protects the ulcer base
• Inhibits pepsin activity
• Prolong action of prostaglandin

Carbenoxolone sodium Adverse Effects:

• It causes salt and water retention so it is not preferred

Question 6. Omeprazole is used in peptic ulcer
Answer:

• Omeprazole is a proton pump inhibitor
• It is used in the treatment of peptic ulcer due to the following mechanism

Question 7. Ranitidine
Answer:

• Ranitidine is an H2 receptor blocker

Ranitidine Uses:

• Duodenal ulcer- provides rapid and marked pain relief
• Gastric ulcer- Heal NSAID-associated ulcers
• Stress ulcers- Occurring in situations like severe burns, trauma, prolonged surgery, etc.
• Zollinger-Elison syndrome
• Gastroesophageal reflux disease
• Prophylaxis of aspiration pneumonia

Question 8. Magnesium sulfate
Answer:

• Magnesium sulfate is a uterine relaxant

Magnesium sulfate  Uses:

• To control convulsions
• To reduce BP in toxemia of pregnancy
• To suppress uterine contractions

Magnesium sulfate  Adverse Effects:

• Cardiac arrhythmias
• Muscular paralysis
• CNS depression
• Respiratory depression

Question 9. Prokinetic drugs
Answer:

• Drugs that promote gastrointestinal motility and speed gastric emptying are called prokinetic agents
• Drugs that are used as prokinetic drugs are
  • Metoclopramide
  • Domperidone
  • Cisapride
  • Mosapride
  • Tegaserod

Question 10. Aluminum hydroxide
Answer:

• Aluminum hydroxide is a weak and slow-acting antacid
• Food interferes with its action
• It is an astringent, so it forms a protective coating over the ulcers
• The aluminum ions relax smooth muscle
• It delays gastric emptying
• It binds to phosphate and prevents its absorption
• It causes constipation

Question 11. Metoclopramide
Answer:

• Metoclopramide is widely used as antiemetic

Metoclopramide  Uses:

• Antiemetic- in postoperative, drug-induced, disease-associated vomiting
• Gastrokinetic- To accelerate gastric emptying
  • Before induction of general anesthesia
  • To assist the passage of the tube into the duodenum
  • To relieve diabetes-associated gastric stasis
• Dyspepsia
• Gastroesophageal reflux disease- provides symptomatic relief

Metoclopramide  Adverse Effects:

• Sedation
• Dizziness
• Diarrhea
• Muscle dystonia
• Long-term use causes:
  • Parkinsonism
  • Galactorrhoea
  • Gynaecomastia

Question 12. Cimetidine and Ranitidine
Answer:

• Cimetidine and ranitidine are H2 blockers

Cimetidine and Ranitidine  Uses:

• Duodenal ulcer- provides rapid and marked pain relief
• Gastric ulcer- Heal NSAID-associated ulcers
• Stress ulcers- Occurring in situations like severe burns, trauma, prolonged surgery, etc.
• Zollinger-Elison syndrome
• Gastroesophageal reflux disease
• Prophylaxis of aspiration pneumonia

Cimetidine and Ranitidine  Adverse Effects

• Headache, dizziness, bowel upset, dry mouth, rashes
• CNS effects- confusion, restlessness, hallucinations
• Antiandrogenic effect of cimetidine

Question 13. Ranitidine preferred over Cimetidine
Answer:

• Ranitidine is preferred over cimetidine because it is:
• More potent
• Longer-acting
• Has no antiandrogenic effects
• No CNS effects as it does not cross BBB
• Does not inhibit microsomal enzymes
• Has mild side effects

Question 14. Classify drugs used in peptic ulcers
Answer:

• Drugs used in the treatment of peptic ulcer are:

1. Reduction of gastric acid secretion

1. H2 Antihistamines

• Cimetidine, Ranitidine, Famotidine, Roxatidine, Loxatidine

2. Proton pump inhibitors

• Omeprazole, Lansoprazole, Pantoprazole, Rabepra- zole

3. Anticholinergic

• Pirenzepine, Propantheline

4. Prostaglandin analogs

• Misoprostol

2. Neutralization of gastric acid- antacids

1. Systemic antacids

• Sodium bicarbonate
• Sodium citrate

2. Non-systemic antacids

• Magnesium hydroxide
• Magnesium trisilicate
• Aluminum hydroxide gel
• Magaldrate

3. Ulcer protection.

• Sucralfate, colloidal bismuth substrate

4. Anti-H pylori drugs

• Amoxicillin, metronidazole, Clarithromycin

Question 15. The rationale of combining aluminum hydroxide gel and magnesium trisilicate as antacids
Answer:

• Aluminum hydroxide gel is slow-acting and delays gastric emptying
• Magnesium trisilicate is fast acting and hastens gastric emptying.
• Combining both leads to:
  • Prolongs the action of the drug
  • Makes it intermediate-acting
  • Maximizes the wanted effects
  • Minimizes the adverse effects
  • Neutralizes luxating effect of magnesium trisilicate
  • Neutralizes constipating effect of aluminum hydroxide

Question 16. Proton pump inhibitors
Answer:

• Protons pump Inhibitors are the most efficient. Inhibitors of the gastric add secretions
• They act by blocking the final step in gastric acid secretions
• They are inactive at neutral pH and only get activated at a pH less than 5
• They are
  • Omeprazole
  • Lansoprazole
  • Pantoprazole
  • Rabeprazole

Proton pump inhibitors Uses:

• Peptic ulcer
• Severe Gastroesophageal reflux disease
• The component in the H.pylori treatment regimen
• Zollinger Ellison syndrome

Question 17. Aspirin is contraindicated in peptic ulcers
Answer:

• Aspirin is contraindicated in peptic ulcer because:
• It irritates gastric mucosa
• It causes gastric distress, nausea, vomiting
• It stimulates CTZ
• In the acidic pH of the stomach, it remains in an unionized form
• Drug particles get attached to the gastric mucosa
• They promote back diffusion of acid in the stomach
• It inhibits prostaglandin synthesis
• Inhibits gastric acid secretions
• Increases production of the mucosa
• This leads to the occurrence of ulcers
• This leads to reduced platelet aggregation
• Promotes bleeding in ulcers

Question 18. Name two drugs used to suppress vomiting
Answer:

• Drugs used to suppress vomiting are called antiemetics

Suppress Vomiting  Classification:

• Anticholinergics- Hyoscine, Dicyclomine
• HI antihistaminics- Promethazine, Diphenhydramine, Dimenhydrinate.
• Neuroleptics- Chlorpromazine, prochlorperazine
• Prokinetic drugs- Metoclopramide, Domperidone, Cisapride
• 5-HT3 antagonists- Ondansetron
• Adjuvant antiemetics- Dexamethasone, benzodiazepines

Question 19. The rationale for using Metoclopramide in vomiting
Answer:

• Metoclopramide is used in vomiting because it
• Increases gastric peristalsis
• Relaxes the pylorus and the first part of the duodenum
• Speeds up gastric emptying
• Blocks D₂ dopamine receptors in the CTZ
• Enhances acetylcholine release from the cholinergic neurons in the gut

Question 20. Promethazine
Answer:

• Promethazine is a highly sedative H1 antagonist

Promethazine  Uses:

• Allergic disorders
• Pruritis
• Common cold
• Preanasethetic medication
• Parkinsonism

Question 21. Bulk purgatives
Answer:

• Bulk purgatives include
  • Bran
  • Plantago seeds
  • Agar
  • Methylcellulose
  • Ispaghula husk
• These are indigestible vegetable fiber and hydrophilic colloids
• It increases volume and lowers the viscosity of intestinal contents
• Used for prevention and treatment of functional constipation
• It requires daily administration for at least 3-4 days
• It forms a large, soft, and solid stool
• A large amount of water must be taken with it

Question 22. Name two osmotic purgatives
(or)
Osmotic purgatives
Answer:

• Osmotic purgatives are solutes that are not absorbed in the intestine
• They retain water osmotically, increase the bulk of intestinal contents, distend bowel, and increase peristalsis to evacuate a fluid stool
• They include

1. Nonabsorbable salts- saline Purgatives

• Magnesium hydroxide
• Magnesium sulfate
• Sodium potassium tartrate
• Sodium sulfate
• Phosphate

2. Nonabsorbable sugars- lactulose

3. Polyethyleneglycol

Question 23. Mention two drugs used in noninfective diarrhea
Answer:

• Drugs used in noninfective diarrhea are:
  • Codeine
  • Diphenoxylate
  • Loperamide

Question 24. Loperamide
Answer:

• Loperamide is an opiate analog
• It is a potent constipating agent
• It has a poor water solubility
• Entry of it into the brain is negligible
• So no CNS effects occur
• It also inhibits GIT secretions
• Abdominal cramps and rashes are common adverse effects
• It is preferred for diarrhea

Question 25. Liquid paraffin
Answer:

Liquid paraffin Advantages

• Liquid paraffin is a viscous inert mineral oil
• It is a mixture of petroleum hydrocarbons
• It lubricates and softens feces
• It is taken for 2-3 days

Liquid paraffin  Disadvantages:

• Unpleasant to swallow
• Interferes with the absorption of fat-soluble vitamins
• Aspiration may cause lipoid pneumonia
• May leak out of the anus causing discomfort
• If absorbed in the intestines causes foreign body granulomas

Question 26. Saline purgatives
Answer:

• Saline Purgatives are nonabsorbable salts
• It includes
  • Magnesium hydroxide
  • Magnesium surface
  • Sodium potassium tartrate
  • Sodium sulfate
  • Phosphate
• They produce 1-2 fluid evacuations within 1-3 hours with mild cramping
• Causes nearly complete emptying of the bowel

Saline purgatives Uses:

• For the preparation of the bowel before surgery and colonoscopy
• In food/drug poisoning
• In the treatment of tapeworm infestations

Question 27. Anthraquinone preparations
Answer:

• Senna and Cascara sagrada are popular anthraquinone preparations
• They contain anthraquinone glycosides
• They are usually administered at bedtime to produce their effect in the morning
• They take 6-8 hours to act
• They are not absorbed in the small intestine
• They pass to the colon where bacteria liberate the active natural form which is later absorbed into the circulation

Anthraquinone preparations  Adverse Effects:

• Skin rashes
• Black pigmentation of colonic mucosa
• Discoloration of urine
• Cramps and excessive purging

Anthraquinone preparations  Contraindications:

• It is contraindicated in lactating mothers

Question 28. Hazards of use of purgatives
Answer:

• Regular use of purgatives may cause
  • Gastrointestinal disturbances
  • Irritable bowel syndrome
  • Loss of electrolytes
  • Loss of salts like calcium in stools
  • Malabsorption
  • Excessive dehydration may lead to death

Question 29. List two purgatives giving an indication for each.
Answer:

Question 30. Mechanism of action and two uses of Domperidone.
Answer:

Domperidone Mechanism of Action:

• It blocks the D₂ receptor in CTZ

Domperidone Uses:

• As an antiemetic – alternative to metoclopramide
• As pre-anesthetic medication – to reduce postoperative vomiting