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Digestive Drug Agents

Digestive Drug Agents. Contents. Antacids Histamine 2 blockers Proton pump inhibitors (PPI) Anti-diarroheal drugs Laxatives Anti-emetics. Peptic ulcer. Peptic ulcer occurs in that part of the gastrointestinal tract which is exposed to gastric acid and pepsin.

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Digestive Drug Agents

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  1. Digestive Drug Agents .

  2. Contents • Antacids • Histamine 2 blockers • Proton pump inhibitors (PPI) • Anti-diarroheal drugs • Laxatives • Anti-emetics

  3. Peptic ulcer • Peptic ulcer occurs in that part of the gastrointestinal tract which is exposed to gastric acid and pepsin. • The etiology of peptic ulcer is not clearly known. It results probably due to an imbalance between the aggressive (acid, pepsin, bile, and H.pylori) and defensive ( gastric mucus, bicarbonate secretion, prostaglandins, and nitric oxide )

  4. Approaches for the treatment PUD • H2-blockers: Cimetidine, ranitidine, Famotidine, and roxitidine • Proton pump inhibitors: Omeprazole, lansoprazole, pantoprazole, rabeprazole, Esomeprazole. • Anticholinergic: Pirenzepine, propantheline, oxyphenonium. • Prostaglandin analogue: misoprostol

  5. Continued • Neutralization of gastric acid • systemic: sodium bicarbonate and sodium citrate • Nonsystemic: mg hydroxide, magnesium trisilicate, aluminum hydroxide gel, and calcium carbonate

  6. Continued • Ulcer protective's: Sucralfate, and bismuth subsalicyte. • Anti-h-pylori drugs: amoxicillin, Clarithromycin, Metronidazole, Tinidazole, and tetracycline.

  7. Antacids • Antacids have been used for centuries in the treatment of patients with acid related disorders. • They were the principle of anti-ulcer treatment until the availability of histamine 2 blockers in the late of 1970s. • The ancient Greece used crushed coral (calcium carbonate)in the first century to treat patients of dyspepsia

  8. Continued • These are basic substances which neutralize gastric acid and raise PH of gastric contents. • Antacids donot decrease acid production, rather agents that raise the antral PH to greater than 4.

  9. Sodium bicarbonate • It is water soluble but the duration of action is short. • It is potent neutralizer, Ph may rise above 7. • It is absorbed systematically, large doses will induce alkalosis • Produces carbon dioxide in stomach, distention, discomfort, belching, risk of ulcer perforation. • Increases sodium load, may worsen edema and CHF.

  10. Continue • However antacids are extensively used, especially on OTC market. • In addition many antacids contain simethicone which reduces gas and bloating. • Basically there are three forms of antacids: • Aluminum antacid • Calcium antacid • Magnesium antacid

  11. Continue • The OTC antacid formulations are available: • Capsules • Tablets • Powders • Chewable tablets • Suspension

  12. Mechanism of action • Antacids originally believed to work by neutralization of gastric acidity. • They donot nothing for prevent over production of acid. • They do this by stimulating: • Mucus • Prostaglandin • Bicarbonate secretion

  13. Drug Effects • The primarily drug effect of antacids is the reduction of the symptoms associated with various acid related disorders such as peptic ulcer disease and hyperacidity. • The ability of antacids to reduce the pain associated with acid related disorders is thought to be result, inhibition of protein digesting ability of pepsin.

  14. Side-Effects • Mg results diarrhea • Al & Ca can result constipation. • Rebound hyperacidity

  15. Aluminum • The amount of antacid necessary to neutralize hydrochloric acid depends on the: • Patient • Condition been treated • Buffering capacity of the preparation used. • Adult dosage is 5-10ml 3-4 times a day, Hs.

  16. Calcium • Calcium carbonate neutralization will produce gas and possible belching, for this reason it may be combined with an anti-flatulent type of drug such as simethicone. • Calcium containing products have a long duration of acid action, which can cause hyperacidity rebound. • Calcium carbonate is available 1-2 tabs Prn.

  17. Magnesium • Mg containing antacids commonly cause a laxative effect and frequent administration of these antacids alone often cannot be tolerated. • Administration of Mg containing antacids is dangerous in patients with renal failure, because of failing of kidney cannot excrete extra Mg and accumulation may occur.

  18. Histamine-2 Blockers • Histamine -2 blockers reduce Hcl but donot abolish stimulated acid secretion. • They have become the most popular drugs for the treatment of many acid related disorders. • These can be attributed by their: • Efficacy • Safety profile • Patient acceptance

  19. Drugs • Cimetidine • Famotidine • Nizatidine • Ranitidine

  20. Mechanism of action • They have ability of blocking parietal cells. • They reduce the amount of Hcl in the parietal cells.

  21. Side-Effects • Confusion • Lethargy • Headache • Abdominal cramp

  22. Cimetidine • In 1977 Cimetidine was the first agent in this class to be released in the market. • Cimetidine comes available 200, 300, 400, 800mg tablets, 300mg/ml, 200mg/ml, 150mg/ml parentral injection.

  23. Proton pump inhibitors (PPI) • PPI is introduced for the treatment of acid related disorders. • The enzyme H+/K+ ATPase is the final common step in acid Secretory processes. • PPI drugs are: • Omeprazole 20mg • Lanzomeprazole 30mg • Esomeprazole 40mg • Pantoprazole 20, 10mg • Rapiprazole 20mg

  24. Mechanism of action • PPI irreversible binds to H+/K+ATPase. The binding of this enzyme prevents the movement of hydrogen ions out of the parietal cell into the stomach, there by blocking all gastric acid secretion. • PPI makes the patient achlorhydric.

  25. Side-effects • Headache • Dizziness • Vomiting • Nausea • Rash • Fatigue

  26. Omeprazole • Omeprazole is a prodrug. • Omeprazole is degraded at low PH and must be given in granules. • Omeprazole inhibits cytochrome P450 system, decreasing metabolism of Warfarin, diazepam, Carbamazepine, and phenytoin and enhancing the effect of these drugs.

  27. Continue • Omeprazole is currently approved only for the acute treatment of severe gastrointestinal reflux disease un responsive to: • Antacids • Antiflatulents • H2-blockers • Adult dosage is 20mg/day for 4-8 weeks.

  28. Ulcer protective agents • Sucralfate: it is compound of aluminum and sucrose which coats the base of the ulcer protecting it from pepsin and acid allowing it to heal. • Dosage is 1gm 1 hour before each meal.

  29. Bismuth Compound • It protects the ulcer by causing coagulation at the base of the ulcer. It has also anti H. pylori action. • It should not be combined with antacids. • The tongue and the stool may appear black after taking dosage 120gm 1 hour before meals and at the bed time.

  30. Prostaglandins • Prostaglandins exert some protective effect on the gastric mucosa and this is why NSAIDs which inhibits prostaglandin synthesis can cause peptic ulceration. • One of the prostaglandin preparation misoprostol reduces the risk of gastric ulcers in patients who are taking NSAIDS, especially in elderly patients having history of ulcers.

  31. Treatment of H. pylori • For helicobacter pylori associated ulcers, there are two therapeutic goals: • Heal the ulcer • Eradication of the organism • The best treatment regimen is for a 10-14 days of Triple Drug regimen.

  32. Continue • The regimen consists of: • PPI, E.g omeprazole 20mg BD • Clarithromycin 500mg BD • Metronidazole 400mg BD

  33. Treatment of NSAIDS associated ulcers • For treatment of aspirin or other NSAIDS induced ulcers the best treatment is to give a proton pump inhibitor, which provides prompt healing of the ulcer. • PPI are also useful in bleeding ulcers as they raise the gastric PH. It is observed that intra gastric PH above 6 may enhance coagulation and platelet aggregation.

  34. Magnesium Case study • ID/CC: A 22 year old female presents to the ER with severe abdominal colic and a history of profuse watery diarrhea of several days duration. • HPI: She also complains dizziness and desire to lose weight, that she has been taken by magnesium sulfate. • PE: Hypotension, lethargy. • Labs: Hypokalemia • Discussion: • Treatment:

  35. Anti-diarrheals Agents • Diarrhea is defined as the abnormal frequent passage of loose stools. • Diarrhea is the abnormal passage of stools with increased frequency, fluidity and weight. • Diarrhea is divided into: • Acute diarrhea • Chronic diarrhea

  36. Causes of Diarrhea • Acute Diarrhea • Bacterial • Drug induced • Viral • Nutritional • Protozoal

  37. Continue • Chronic Diarrhea • Tumors • Diabetes mellitus • Hyperthyroidism • Addison's disease • Irritable bowl syndrome

  38. Anti-diarrhoe Agents • Electrolytes • Bulk agents • Absorbents • Anti-inflammatory • Opioids • Intestinal flora modifiers

  39. Bismthus subsalicyte • Bismuth subsalicte is a pregnancy category C agent. • It should be used with caution in children and teenagers who have or are recovering from chicken pox or flu because of attendance risk of Reyes syndrome.

  40. Continue • Bismuth subsalicyte have two harmless side-effects: • Darkening of the stool • Darkening of the tongue • It is available in a OTC drug. • Available 262 mg chewable tablet and 262 mg/15ml suspension.

  41. Attapulgite • Attapulgite has replaced the use of kaolin-pectin in this preparation. • Kaolin is a naturally hydrated aluminum compound that is now rarely used as an anti-diarrheal agents. • How ever pectin which is extracted from the apples or citrus fruit and is used in many combination products.

  42. Continue • The original kaopectate contained 980mg/5ml of kaolin and 21.7 mg/5ml of pectin. • Attapulgite is an OTC agent. • It is a pregnancy category C agent. • Available 300mg chewable tablet and 600mg/15ml solution.

  43. Diphenoxylate & Atropine (Lomotil) • Lomotil is a synthetic opiate agonist that is structurally related to meperidine. • It has little or no analgesic activity. • It is classified in a pregnancy category C agent. • Available as 2.5mg/5ml + 0.025mg/5ml atropine solution, and 2.5mg + 0.025mg, diphenoxylate and atropine respectively.

  44. Loperamide • Loperamide is a synthetic anti-diarrheal that similar to diphenoxylate. • Decreases the number of stools and water content. • It is the only opiate anti-diarrheal agent that is available as an OTC medication. • Loperamide is a pregnancy category B agent. • Available 1mg tab, 1mg/5ml oral.

  45. Lactobacillus acidophilus • Lactobacillus acidophilus is an acid producing bacteria prepared in a concentrated oral administration. • Has been used for more than 75 years in the treatment of uncomplicated diarrhea, particularly that caused by antibiotic treatment that destroys normal florae.

  46. Continue • It is an OTC medication. • Available 1g powder, 1g tablet, and 1g capsules.

  47. Laxatives • Laxatives are used for the treatment of constipation, which is defined as a condition of abnormally infrequent and difficult passage of feces through the lower GIT. • Constipation is not a disease but it is a symptom of disease.

  48. Causes of Constipation • Pregnancy • Hypothyroidism • Hypokalemia • Parkinsons disease • Iron supplements • Anti-cholinergics • Poor fluid intake

  49. Continue • Lack of exercise • Anxiety • Stress • AL-antacids

  50. Classification of Drugs • Bulk-forming agents • Methylcellulose • Psyllium • Polycarbophil • Stool Softeners- Emollient • Docusate salts • Mineral oil • Glycerin

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