In this essay we will discuss about the drugs used for the treatment of dyspepsia and gastro-esophageal reflux disease:- 1. Non-Systemic Antacids 2. Systemic Antacid 3. Alginates 4. Surface Anesthetics 5. Acid Release Inhibitors 6. Pro-Kinetic Drugs or Motility Stimulants.
1. Non-Systemic Antacids:
Aluminum and magnesium containing antacids are relatively insoluble, very poorly absorbed, longer acting and most suitable for most antacid purpose. Liquid preparations are more effective than tablets. Magnesium trisilicate or magnesium carbonate is the commonly used magnesium salts for dyspepsia. They may cause diarrhea. Aluminum hydroxide in addition to reducing acidity also inactivates gastric pepsin. This antacid is slightly astringent and can cause constipation.
2. Systemic Antacid:
Sodium bicarbonate dissolved in water is used occasionally when a rapid relief of dyspepsia is intended. It should not be used for prolonged periods, as it causes alkalosis, which may lead to aggravation of hepatic, renal and cardiovascular disorders.
Compound antacid preparations:
Activated dimethicone (simethicone) is added to non-systemic antacid as an antifoaming agent to relieve flatulence. Such a combination may also be useful for the relief of hiccup in palliative care.
3. Alginates:
Alginates float on the gastric contents and can also be added to an antacid, which protects the mucosa of the lower esophagus in case of a reflux and may be useful against gastro-esophageal reflux disease.
4. Surface Anesthetics:
Oxetacaine added to an antacid is of doubtful efficacy in gastro-esophageal reflux disease.
5. Acid Release Inhibitors:
Proton pump inhibitors (e.g. omeprazole) are the most potent inhibitors of gastric acid secretion and are indicated in severe gastro-esophageal reflux disease, which do not respond to combined antacid preparation.
6. Pro-Kinetic Drugs or Motility Stimulants:
These are the drugs that improve gastro-esophageal sphincter function and accelerate gastric emptying and small intestine transit. They include metoclopramide, domperidone (dopamine antagonists) and cisapride (cholinomimetic).
Metoclopramide and domperidone are mainly used in nonspecific and cytotoxic induced nausea and vomiting due to their selective action on the CTZ, where their pro-kinetic action further acts as contributing factor for antiemesis. They may induce an acute dystonic action, particularly in young women and children.
Cisapride, a pro-kinetic drug, is believed to promote release of acetylcholine in the gut wall. It does not have dopamine antagonist action as possessed by metoclopramide and domperidone. It is quite useful in gastro-esophageal reflux, gastric stasis and dyspepsia.
The most serious side effect of cisapride is serious cardiac arrhythmia, which may be even fatal. Others include abdominal cramps, diarrhea, hypersensitivity reaction and increased urinary frequency. Cisapride is contraindicated in heart diseases with a family history of QT interval prolongation or ventricular arrhythmia.