ANTIULCER DRUGS:
Antiulcer drugs or medications which block the pathways of acids production or secretion, decreasing gastric acidity, improving symptoms and aids in healing of acid peptic diseases.
DEFINITION:
Antiulcers are a class of drugs exclusive of antibacterial agents and used to treat ulcers in stomach and upper part of small intestine.
Classification of Antiulcer Drugs:
Antihistamines:
- Cimetidine
- Famotidine
- Roxatidine
- Ranitidine
- Nizatidine
Proton Pump inhibitors:
- Omeprazole
- Pantoprazole
- Esmoprazole
- Lansoprazole
- Rabeprazole
Anticholenergics:
- Pirenzepine
- Oxyphenonium
- Propantheline
Prostaglandin Analogue:
- Misoprostol
Acid Neutralizing Agents (Antacids):
- Systemic: Sodium bicarbonate
- Non-systemic: Calcium carbonate
Anti H.Pylori Drugs:
- Amoxicillin
- Tetracycline
- Clarithromycin
- Tinidazole
- Metronidazole
Ulcer Protectives:
- Sucralfate
- Colloidal bismuth sub citrate
Pharmacokinetics:
Bioavailability: Approximately 50% (instability at acidic pH).
Metabolism: Antiulcers are metabolized by liver.
Excretion: Metabolites are excreted through renal system.
Duration of action: 24 hours
Mechanism of Action:
- Block last step in secretion of gastric acid by combining with hydrogen,potassium and adenosine triphosphate in parietal cells of stomach.
- React covalently with SH groups of H+K+ATPASE enzyme and inactivate it irreversibly.
- Acid secretion resumes only when new H+K+ATPASE molecules are synthesized.
Therapeutic Uses of Antiulcer Drugs:
- Promote healing of duodenal
- Gastric ulcers
- Peptic Ulcers
- Stress ulcer
- GERD
- Aspiration Pneumonia
- Zollinger Ellison Syndrome
- Bleeding peptic ulcer
Adverse effects of Antiulcers:
- Nausea
- Constipation
- Headache
- Diarrhea
- Depression
- Joint Pain
- Cramping
- Hives
- Leucopenia
- Rashes
- Hepatic Dysfunction
- Hepatic Dysfunction
- Erectile Dysfunction
- Abdominal pain
Drug Interaction:
Antiulcer drugs inhibits oxidation of certain drugs, diazepam, phenytoin and warfarin.
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