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Gastrointestinal Agents ( GIA)

Gastrointestinal Agents ( GIA)

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Gastrointestinal Agents ( GIA)

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  1. Gastrointestinal Agents ( GIA)

  2. Inorganic agents used to treat GIT • Inorganic agents used to treat gastrointestinal disorders include: • Products for altering gastric pH • -Acidifying Agents: Used to treat achlorhydria (absence of HCl in the gastric secretion) • e.g.- Diluted HCl • -Antacids: Used to treat hyperchlorhydria and peptic ulcer. • 2) Protectives for intestinal inflammation • 3) Adsorbents for intestinal toxins • 4) Cathartics or laxatives for constipation

  3. Acidifying Agents • Achlorhydria is the absence of HCl in the gastric secretion. Lt is common in otherwise normal individual after age 50 years. • Gastric HCl functions by killing the bacteria in ingested food& drink, softening fibrous food, promoting formation of the proteolytic enzyme, pepsin.

  4. The symptoms of achlorhydria • 1-mild diarrhea( frequent bowel movement) • 2-epigastreic pain ( upper abdominal pain ). • 3- sensitive to food ( spicy ).

  5. Treatment of Achlorhydria • Dilute HCl solution ( 200ml ) prepared . • Dose 15ml for each . • The use of dil HCl because to avoid exposure of dental enamel

  6. Antacids • Agents are given or administered to neutralize excess HCl which may be causing pain & possible ulceration.

  7. When anatcids are described? • 1- uncomfortable feeling from over eating • 2-heartburn • 3-A growing hungry feeling between meals.

  8. Treatment of hyperacidity • 1- Anticholinergic agents. • 2- Inorganic antacids ( Aluminum hydroxide and Magnesium hydroxide ). • 3-In case of ulceration, H2 –antagonist • Cimetidine, Ranitidine, … • 4-Bed rest • 5- Surgical if necessary ( Bleeding ).

  9. Hyperacidity developed , the result can range from gastritis ( inflammation of gastric mucosal to peptic ulcer.A peptic ulcer can be located in the lower end of the esophagus. • Also, stomach ulcer( gastric ulcer), duodenum ulcer.

  10. Patients suffering from burn, which is due to gastric acid entering the esophagus either a blechor upon lying in bed ( Reflux ). • Frequently, these people obtained relief by sleeping in a bed elevated at the head to reduce the flow of gastric fluid from the stomach into esophagau.

  11. Types of peptic ulcers • There are TWO types. • 1- chronic ulcer. • 2- acute ulcer. • Chronic ulcer rather than acute , • Complications will include hemorrhage , may be leads to other disease ( CA).

  12. Treatment of Ulcer • Range from diet • Antacids • Anticholinergic agents.

  13. Antacids Therapy • Antacids are alkaline bases used to neutralized the excess gasrtic HCl associated with gastric & peptic ulcers.

  14. Antacids Products( drugs) • * Sodium bicarbonate Na2HCO3 • **Aluminum antacid products • *** Magnesium antacid products. • Combination therapy( Al + Mg) products. • Maloox . • There is no ideal antacids

  15. Selection of pharmaceutical Anatcids • The antacid should not be absorbable or cause systemic alkalosis. •  It should not be laxative or cause constipation •  It should buffer in the pH 4-6 range •  It should be rapidly effective and maintain its effect over a long period of time. •  It should probably inhibit pepsin but should not completely inactivate peptic digestion. •  It should not produce rebound acidity or excessive eructation (belching). •  It should not cause large evolution of gas by reacting with gastric HCl. •  It should not affect the absorption of food, nutrient and vitamin. •  It should be non-irritant to stomach, intestine and should not cause diarrhea. •  It should be non-toxic, and palatable. •  It should be cheap and available.

  16. Criteria for antacid products • In order for a product to be labeled an antacid according to FDA Antacid Panel it must consist of one or more approved (active) ingredients. • Each active ingredient must contribute at least 25% of the total acid-neutralizing capacity of the product. •  The finished product must contain at least 5mEq/dose unit of acid-neutralizing capacity and raise the pH of gastric secretions to 3.5 or greater within 15 minutes. •  No more than four active antacid ingredients can be combined in any one product

  17. Classification of Antacids • Antacids are commonly classified in two groups: • Systemic Antacids & Nonsystemic antacids • Systemic Antacids: • Antacids(water soluble) which are absorbed in the systemic circulation (usually from the gut) and may cause metabolic alkalosis are called systemic antacids. • Common systemic antacids are: Sodium Bicarbonate, Sodium citrate, Sodium acetate, and Potassium citrate

  18. On systemic Antacids: • Antacids which are not absorbed from the gut and does not interrupt acid base balance (metabolic alkalosis) are called nonsystemic antacids. • Non systemic antacids are divided into-Buffer antacid & Non-buffer antacid. • Buffer antacid:They limit the rise in pH of the gastric contents to below neutrality. • e.g. Aluminum Hydroxide Gel [Al(OH)3], Magnesium hydroxide [Mg(OH)2], Magnesium Trisilicate [2MgO.3SiO2.xH2O] • Non-buffer antacid:They potentially permit the elevation in pH even above neutrality. • e.g. Calcium carbonate [CaCO3], Calcium phosphate [Ca3(PO4)2], Magnesium oxide [MgO], Magnesium Carbonate [MgCO3]

  19. Sodium bicarbonate NaHCO3 • Sodium bicarbonate USP ( Baking Soda ) • Used as antacids it can cause sharp increase in gastric pH up to 7 • HCl + NaHCO3 NaCl + H2O + CO2 • It is readily absorbed and sodium retention can result with continued use.

  20. Sodium bicarbonate USP • Usual Dose ; 300mg- 2g four times daily • May be found in many combination therapy

  21. Side effects of Sodium bicarbonate • 1- it is readily absorbed. • 2- it will inhibit the absorption of tetracyclines. • 3- increase blood pressure. • 4- Bad taste and form gases.

  22. .To overcome this problem • Combination therapy between the sodium bicarbonate + Citric acid • May form effervescent

  23. Aluminum containing antacids • Widely used, they are nonsystemic & • pH =3- 5 • Because of libration of astringent aluminum cations Al +++, they ten to be constipation • Most cause increased fecal phosphate excreation due to formation of insoluble Aluminum phosphate in the intestine tract.

  24. Types of Aluminium products • There are TWO types • 1- Aluminum hydroxide gel ( suspension) • 2- Aluminum hydroxide gel Tablets • Both gel and dry aluminum are popular antacids ( Famous) • Dose 5ml to 30 ml for suspension • 1 to 4 chewable tablets.

  25. The onset of action of the latter (Dried gel..)is slower, deepening on patient must first chew the tablet or simply suck on the tablet. • The degree of chewing will determine how finely divided will be the particles.

  26. A problem with the gels is that of a loss of antacids properties on aging .This is more of a problem with dried gel than with the liquid suspension and seems to be related to the manufacturing process. • The rate of loss of antacids action is de-pendent upon pH used to ppt the gel.

  27. The Al hydroxide gels are nonabsorbable and exert little. • If the gel is formed by ppt in a carbonate,/bicarbonate system, they may be some evolution in of CO2 ,due to reaction between HCl and HCO3-

  28. Al hydroxide gel may be adsorb pepsin and interfere with adsorption with other drugs. • May be cause constipation , nausea, vomiting,. • For long period may be cause phosphate deficiency.

  29. Calcium containing Antacids • Those used in medicine as CaCO3 are poorly absorbed salts which will only go into solution • CaCO3 Ca +2 +CO3 H2CO3 • H2O + CO2

  30. Disadvantages • Make gases • Constipation • Contraindicated in patients with renal disease. gastric hemorrhage , hypertension, dehydration of electrolytes.

  31. Magnesium containing Antacids • There are a large number of official magnesium antacids . They are porrly soluble salts & rate of dissolution is slow. • The problem is Magnesium carbonate • (MgCO3)4. Mg(OH)2.5H2O are laxatives • Dose ; 500 mg four times daily.

  32. Magnesium Hydroxide Mg(OH)2 • It is white powder, insoluble iun water,alcohol,only dissolve in dil acids • Mg(OH)2 = Mg +2 + 2OH- -- 4H2O • At high doses, magnesiumhydtoxide used as Laxative. • When used as antacid usually found as combination therapy with Al. • Dose 300-600mg

  33. Combination Therapy • Because no single antacids meets all the criteria for an ideal antacids, several combination therapy products of antacids • 1-Aluminum hydroxide gel+ Magnesium hydroxide ( Aludrox) ( Maalox ) • Found as Tablet or suspension ( Not laxative and not constipation)

  34. Maalox Tablet or Suspension

  35. Gaviscon • Alginic acid + Sodium bicarbonate mixture • Attempt to provide relife of reflux esiphagus . • The bulk tablet is chewed. • Alginic acid is hydrophilic colloidal carbohydrate obtained from sea weed. • It make foam which floate on the top pf stomach.

  36. Chewable Tablet

  37. Protective's & Adsorbents • Agent are used for treat mild diarrhea • Diarrhea is a symptom and not a disease • Diarrhea may be acute or chronic • Acute diarrhea can be caused by bacteria , toxin, chemical poisons, drugs, allergy, disease

  38. Damage or irritation to that of causing electrolytes to flow from body fluids into intestinal tract.( Short Time ) • Electrolytes should be given to the patients.

  39. Diarrhea is a serious condition, particularly for very young or elderly patients. • The loss of fluids & electrolytes can quickly lead to dehydration and electrolyte imbalances. • It is believed that some of the bacterial toxins stimulate the flow of electrolytes into the intestine.

  40. Thereby increasing the intestinal osmoticload.

  41. Chronic diarrhea • Can result from gastrointestinal surgery, carcinoma, chronic inflammation. • The chronic diarrhea for long time • The loss of electrolytes and fluids can quickly lead to dehydration and electrolytes imbalance.

  42. Drugs used for treatment • 1- Adsorbent • 2-Antispasodic agent (organic agent ) • 3-Antibacterial ( Tetracycline)

  43. 1- Adsorbents • Protective agents supposed to adsorb toxins, bacteria & viruses. • Bismuthsalts. [Bi(OH)2NO3]]4.BiO(OH). • Clays • Activated charcoal

  44. Bismuth products • Milk of Bismuth ( Bismuth cream ) • A suspension contains bismuth hydroxide and bismuth subcarbonate . • Are water insoluble, may act as mild astringent and antiseptic action.

  45. Bismuth subcarbonate • It is USP, the chemical formula is: • [(BiO)2CO3]2 .H2O • Insoluble in H2O,but soluble in acids. • It is protective agent.

  46. clays • Kaolin is a native hydrate aluminum silicate • It is found in earth as clay, some times added to pectin used for children

  47. It occurs as a soft,white or fait tyellow, when mix with H2O assumes a darker color and clay odor. • It is insoluble with H2O .It is usually found together with the vegetable bcarbohydrate pectin . • It is used as adsorbent. • It is interfer with Lincomycin

  48. Activated Charcoal USP • Used as adsorbent in the treatment diarrhea • Now the drug of choice for poisoning as antidote. • Activated charcoal is recommended as a component of first aid kits. • Also, may be used as filter in gas mask. • It adsorb CO2,N2O, O2, N2, Amines,NH3,

  49. Activated Charcoal is used in filters of gas masks because of its ability to adsorb gases.