Antiulcer

Ulcers

• Ulcers are open sores or wounds on the skin or lining of the digestive tract, caused by loss of tissue due to various factors.

Types of Ulcers

• Peptic ulcer: found in the stomach, duodenum (first part of the small intestine), or esophagus
• Genital ulcer: found in the genital area
• Esophageal ulcer: found in the esophagus
• Pressure ulcer: found in individuals who are confined to bed

Factors Contributing to Ulcers

• Imbalance of digestive fluids (HCl, pepsin)
• Infection with Helicobacter pylori
• Ingestion of NSAIDs (non-steroidal anti-inflammatory drugs)
• Stress

Treatment of Ulcers

• H2 receptor blockers (e.g. cimetidine, ranitidine)
• Proton pump inhibitors (e.g. omeprazole, pantoprazole, lansoprazole)
• Muscarinic antagonists (e.g. pirenzepine)
• Antacids (e.g. sodium bicarbonate, magnesium hydroxide)
• Prostaglandin analogues (e.g. misoprostol)

H2 Receptor Blockers

• Mechanism of action: competitively block histamine receptors, reducing acid secretion
• Adverse effects: headache, dry mouth, confusion, bradycardia, cardiac arrest

Proton Pump Inhibitors

• Mechanism of action: inhibit the proton pump, reducing acid secretion
• Adverse effects: nausea, diarrhea, headache, muscle pain, rashes

Muscarinic Antagonists

• Mechanism of action: block muscarinic receptors, reducing acid secretion
• Adverse effects: dry mouth, blurred vision, anticholinergic effects

Prostaglandin Analogues

• Mechanism of action: increase production of mucus and bicarbonate, protecting the mucosa
• Adverse effects: diarrhea, uterine bleeding, inflammatory bowel disease

Antacids

• Mechanism of action: neutralize acid, inhibit pepsin
• Adverse effects: systemic alkalosis, discomfort, bloating### Antacids
• Sodium Bicarbonate has potent neutralizing capacity and is used to treat heartburn.
• It can raise pH above 7, which may decrease the effect of certain medications.

Systemic vs Non-Systemic Antacids

• Systemic antacids (e.g. Sodium Bicarbonate) can be absorbed into the bloodstream and may cause side effects.
• Non-systemic antacids (e.g. Aluminum Hydroxide, Magnesium Hydroxide) are not absorbed and are less likely to cause side effects.

Magnesium-Based Antacids

• Magnesium Hydroxide reacts with HCl to form MgO and water, which can cause constipation and osteomalacia.
• Magnesium Trisilicate reacts with HCl to form MgCl and water, which can cause osmotic diarrhea.

Aluminium-Based Antacids

• Aluminium Hydroxide can cause constipation, osteomalacia, and aluminum toxicity, which can lead to encephalopathy.

Miscellaneous Antacids

• Simethicone reduces surface tension and prevents bubble formation, which can help prevent reflux.
• Alginates form a layer of foam on top of gastric contents, reducing reflux.
• Oxethazine is a surface anesthetic that can help reduce pain.

Sucralfate

• Sucralfate polymerizes by cross-linking to form a sticky substance that adheres to ulcer craters, providing a physical barrier.
• It can cause constipation and hypophosphatemia.

Colloidal Bismuth

• Colloidal Bismuth coats the ulcer crater with a layer of mucus, providing a protective barrier.
• It can cause the tongue, stools, and dentures to turn black.

Subcitrate (CBS)

• Subcitrate is a mucous bicarbonate that can help protect the ulcer crater.
• It can cause osteodystrophy and encephalopathy.

Antibiotics/Eradication of H.pylori

• Triple therapy involves using 2 antibiotics and 1 acid-reducing agent to eradicate H.pylori.
• The best triple therapy regimen is Omeprazole/Lansoprazole + Clarithromycin + Amoxycillin/Metronidazole.
• Quadruple therapy involves using 4 medications to eradicate H.pylori.