How Drug can Affect Digestive System and What is Drug Than Can Affect Digestive System?
Digestive System is Complex network of organ and structure working together to break down food and absorbing nutrient and used to eliminate body waste, It is composed by by Stomach, small intestine, Large intestine, esophagus and Mouth.
Before we focus on how drug affect digestive system we Have to know how the digestive system work and its disorder. A student nurses or Nurses should first Think on Gastro intestinal disorder.
List of different disorder occur in Gastro intestinal system.
Peptic Ulcer disease(PUD), Gastro Esophageal reflux Disease(GERD), Zollinger elision syndrome, Esophagitis, GI bleeding, Stress ulcer, Diarrhea
Heart burn.
Some cause of PUD
Imbalance between cell-destructive and cell-protective effect, Helicobacter pylori.
Drugs Affecting Gastrointestinal Secretions
Drugs typically used to affect GI secretions in treating peptic ulcer disease and disorders involving increased GI acid work to decrease GI secretory activity, block the action of GI secretions, or form protective coverings on the GI lining to prevent erosion from GI secretions.
The drugs used to treat gastroesophageal reflux disease (GERD) and ulcer disease include:
Histamine-2 (H2) antagonists, which block the release of hydrochloric acid in response to gastrin.
Antacids, which interact with acids at the chemical level to neutralize them.
Proton pump inhibitors, which suppress the secretion of hydrochloric acid into the lumen of the stomach.
GI protectants, which coat any injured area in the stomach to prevent further injury from acid.
Prostaglandins, which inhibit the secretion of gastrin and increase the secretion of the mucous lining of the stomach, providing a buffer.
1.Gastric Acid Inhibitor (Anti secretory Drugs)
In this class we have the Proton pump inhibitor(PPI), These drugs bind to H+,K+-ATPase to prevent the pumping or release of gastric acid into the stomach lumen and therefore block the final step of acid production. Omeprazole, esomeprazole, lansoprazole, pantoprazole, and rabeprazole are available PPIs.
Omeprazole.
omeprazole is indicated for the PUD,errosive gastratis, gastroesophageal reflux disease(GERD) and zollinger Ellison syndrome.
Have minimal Adverse effects Such nausea, diarrhea and headache,
2. Histamine-2 Receptor Blocker (H2RB) Agents.
These drugs inhibit the action of histamine at histamine H2 receptor cells of the stomach, which then reduces the secretion of gastric acid and reduces total pepsin output.
This drug is Indicated to be used for the medical treatment of a gastric or duodenal ulcer, gastric hypersecretory (excessive gastric secretion of hydrochloric acid) conditions, and GERD. These drugs may also be used as prophylaxis of stress-related ulcers and acute upper GI bleeding in critically ill patients
Adverse reactions of the histamine H2 antagonists include dizziness, somnolence, headache, confusion, hallucinations, diarrhea, and impotence (that is reversible when the drug is discontinued).
Antacids.
Antacids are a group of inorganic chemicals that neutralize stomach acid.
Antacids are available OTC, and many patients use them to self-treat a variety of GI symptoms.
There is no one perfect antacid. The choice of an antacid depends on adverse effect and absorption factors.
Available agents are sodium bicarbonate (Bell-ans), calcium carbonate (Oystercal, Tums, and others), magnesium salts (Milk of Magnesia and others), aluminum salts (Amphojel and others), magaldrate (Riopan).
Therapeutic Actions and Indications.
Antacids neutralize stomach acid by direct chemical reaction. They are recommended for the symptomatic relief of upset stomach associated with hyperacidity, as well as the hyperacidity associated with peptic ulcer, gastritis, peptic esophagitis, gastric hyperacidity, and hiatal hernia.
Contraindications and Cautions.
Allergy to antacid products or any component of the drug to prevent hypersensitivity reactions.
Caution, Any condition that can be exacerbated by electrolyte or acid–base imbalance to prevent exacerbations and serious adverse effects, any electrolyte imbalance, which could be exacerbated by the electrolyte-changing effects of these drugs, GI obstruction, which could cause systemic absorption of the drugs and increased adverse effects, Renal dysfunction, which could lead to electrolyte disturbance if any absorbed antacid is not neutralized properly, pregnancy and lactation because of the potential for adverse effects on the fetus or neonate.
Adverse effect.
The adverse effects associated with these drugs relate to their effects on acid–base and electrolyte balance.
Administering an antacid frequently causes acid rebound, in which the stomach produces more acid in response to the alkaline environment. Neutralizing the stomach contents to an alkaline level stimulates gastrin production to cause an increase in acid production and return the stomach to its normal acidic state.
In many cases, the acid rebound causes an increase in symptoms, which results in an increased intake of the antacid. This leads to more acid production and an ongoing cycle. When more and more antacid is used, the risk for systemic effects rises. Alkalosis with resultant metabolic changes (nausea, vomiting, neuromuscular changes, headache, irritability, muscle twitching, and even coma) may occur.
Tri -Therapy Against H. pylori Bacteria
Standard “tri-therapy”
Bismuth+ Metronidazole + Amoxycilline (for 2 weeks), Eradication rate of H.pylori is 70-80% of patients. Omeprazole + Metronidazole + Clarithromycine (for one week), Eradication rate of H.pylori is 95-100% of patients .
PPI + clarithromycin +amoxicillin, Omeprazole 20mg bid+clarithromycin 500mg bid+amoxicillin 1gr bid for 7 days then omeprazole 20mg OD for 3 weeks. PP I+ amoxicillin + tinidazole, Omeprazole 20mg bid+clarithromycin 500mg bid+metronidazole 500mg bid for 7 days then omeprazole 20mg OD for 3 weeks.
GI Protectant drugs
GI protectants coat any injured area in the stomach to prevent further injury from acid. Sucralfate (Carafate) is the only GI protectant currently available
Therapeutic Actions and Indications of GI protectant Drugs.
Sucralfate forms an ulcer-adherent complex at duodenal ulcer sites, protecting the sites against acid, pepsin, and bile salts.
This action prevents further breakdown of the area and promotes ulcer healing.
The drug also inhibits pepsin activity in gastric juices, preventing further breakdown of proteins in the stomach, including the protein wall of the stomach
Contraindications and Cautions.
Known allergy to the drug or any of its components to prevent hypersensitivity reactions. Renal failure or undergoing dialysis because a buildup of aluminum may occur if it is used with aluminum-containing products.
Caution are pregnant or lactating because of the potential adverse effects on the fetus or neonate.
Prostaglandins
Prostaglandins are used to protect the stomach lining.
The prostaglandin available for this use is the synthetic prostaglandin E1 analogue misoprostol (Cytotec).
Therapeutic Actions and Indications
Prostaglandin E1 inhibits gastric acid secretion and increases bicarbonate and mucous production in the stomach, thus protecting the stomach lining.
Misoprostol is primarily used to prevent NSAID-induced gastric ulcers in patients who are at high risk for complications from a gastric ulcer (e.g., elderly or debilitated patients, patients with a past history of ulcer).
Contraindications and Cautions.
Allergy to any part of the drug to prevent hypersensitivity reactions. Pregnancy because it is an abortifacient. Women of childbearing age should be advised to have a negative serum pregnancy test within 2 weeks of beginning treatment, and they should begin the drug on the second or third day of their next menstrual cycle. In addition, they should be instructed to use barrier contraceptives during therapy.
Caution: lactation because of the potential for adverse effects on the newborn. hepatic or renal impairment, which could interfere with the effective metabolism and excretion of the drug.