1. Gastrointestinal agents

2. Gastrointestinal agents Acidifiers: Ammonium chloride* and Dil. HCl
nonliving
Gastrointestinal agents
Acidifiers: Ammonium chloride* and Dil. HCl
Antacid: Ideal properties of antacids, combinations of antacids, Sodium Bicarbonate*, Aluminum hydroxide gel, Magnesium hydroxide mixture
Cathartics: Magnesium sulphate, Sodium orthophosphate, Kaolin and Bentonite
Antimicrobials: Mechanism, classification, Potassium permanganate, Boric acid, Hydrogen peroxide*, Chlorinated lime*, Iodine and its preparations
Disinfectants
Living
Kill
Antiseptic
Germicides
Bacteriostatic
An antacid is a substance which neutralizes stomach acidity, used to relieve heartburn, indigestion or an upset stomach
Acidifiers are inorganic chemicals that either produce or become acid
Antimicrobial agents are the
chemicals and their preparation in reducing or preventing infection
due to microorganisms
In medicine, a cathartic is a substance that accelerates defecation

3. Acidifiers are inorganic chemicals that either produce or become acid
Gastric acidifiers, used in controlling pH in stomach.
Urinary acidifiers, used in controlling pH in urine.
Systemic acidifiers, used in controlling pH in all the parts of body.

4. Antacids: Mechanism of Action
Promote gastric mucosal defense mechanisms
Secretion of:
Mucus: protective barrier against HCl
Bicarbonate: helps buffer acidic properties of HCl
Prostaglandins: prevent activation of proton pump which results in  HCl production

5. Antacids: Mechanism of Action (cont'd)
Antacids DO NOT prevent the over-production of acid
Antacids DO neutralize the acid once it’s in the stomach
They have a quick onset of relief but last for a short duration.
They have a quick onset of relief but last for a short duration.

6. Antacids: Drug Effects
Reduction of pain associated with acid-related disorders
Raising gastric pH from 1.3 to 1.6 neutralizes 50% of the gastric acid
Reducing acidity that reduces pain

7. Antacids (cont'd)
Used as alone or in combination with other antacids that may reduced constipation.

8. Antacids: Aluminum Salts
Forms: carbonate, hydroxide
Have constipating effects
Often used with magnesium to counteract constipation
Examples
Aluminum carbonate: Basaljel
Hydroxide salt: AlternaGEL
Combination products (aluminum and magnesium): Gaviscon, Maalox, Mylanta, Di-Gel

9. Antacids: Magnesium Salts
Forms: carbonate, hydroxide, oxide, trisilicate
Commonly cause diarrhea; usually used with other antacid agents to counteract of this undesirable effect
It is dangerous, when used with renal failure or disease —the failing kidney cannot excrete extra magnesium, resulting in hypermagnesemia

10. Antacids: Magnesium Salts (cont'd)
Examples
Hydroxide salt: magnesium hydroxide Mg(OH)2
Carbonate salt: Gaviscon (also a combination product)
Combination products such as Maalox, Mylanta (aluminum and magnesium)

11. Antacids: Calcium Salts
There are different forms to be prepared but the most common is carbonate of calcium.
They may cause constipation after taking.
They may cause kidney stones.
Long duration of acid action may cause increased gastric acid secretion (hyperacidity rebound)
Often advertised as an extra source of dietary calcium
Example: Tums (calcium carbonate)

12. Antacids: Sodium Bicarbonate
It is highly soluble in nature
Buffers have acidic properties to counter HCl
Quick onset, but short duration
May cause metabolic alkalosis
Sodium content may cause problems in patients with hypertension, or renal insufficiency (fluid retention)

13. Antacids and Antiflatulents
Antiflatulents: used to relieve the painful symptoms associated with gas
Several agents are used to bind or alter intestinal gas and are often added to antacid combination products

14. Antacids and Antiflatulents (cont'd)
OTC antiflatulents
Activated charcoal
Simethicone
Alters elasticity of mucus-coated bubbles, causing them to break
Used often, but there are limited data to support effectiveness

15. Antacids: Side Effects
Minimal, and depend on the compound used
Aluminum and calcium
Constipation
Magnesium
Diarrhea
Calcium carbonate
Produces gas and belching; often combined with simethicone
Excess use of any calcium ant acid can cause kidney stones
Rebound of hyperacidity with overuse of these medications
Long-term self medication of these medications can mask more serious problems such as bleeding ulcers or malignancies, pt with ongoing symptoms should see a physician b/c other meds ma need to be used to control the hyperacidity or r/o more serious conditions.

16. Antacids: Drug Interactions
Adsorption of other drugs to antacids
Reduces the ability of the other drug to be absorbed into the body
Chelation
Chemical binding, or inactivation, of another drug
Produces insoluble complexes
Result: reduced drug absorption
Increased stomach pH- increase adsorption of the basic drug and decreased absorption of the acidic drugs.
Decreased stomach pH-increases excretion of the acidic drug and decreases excretion of the basic drug.
Most drugs are either weak acids or weak bases. Therefore, pH conditions in both the GI and urinary tracts will affect the extent to which drug molecules are ionized (changed)

17. Antacids: Nursing Implications
Assess for allergies and preexisting conditions that may restrict the use of antacids, such as:
Fluid imbalances – Renal disease – HF(heart failure)
Pregnancy – GI obstruction
Patients with HF or hypertension should use low-sodium antacids such as Riopan, Maalox, or Mylanta II

18. Antacids: Nursing Implications
Use with caution with other medications due to the many drug interactions
Most medications should be given 1 to 2 hours after giving an antacid
Antacids may cause premature dissolving of enteric-coated medications, resulting in stomach upset

19. Antacids: Nursing Implications
Monitor for side effects
Nausea, vomiting, abdominal pain, diarrhea
With calcium-containing products: constipation, acid rebound
Monitor for therapeutic response
Notify heath care provider if symptoms are not relieved

20. Ideal properties of antacids
Ideal Characteristics of Antacid
~>should not absorbable or cause systemic alkalosis.
~>should not liberate carbon dioxide &cause rebound hyperacidity.
~>should not interfere with absorption of food.
~>should not be a laxative or cause constipation.
~>should be quick acting & exert its effect over a longer period of time.
~>should buffer in the pH range 4-6.
~>should probably inhibit pepsin.
~>should be palatable & inexpensive.
~>should be insoluble in water.

21. Abnormal frequent passage of loose stool.
Diarrhea
Abnormal frequent passage of loose stool.
Or Abnormal passage of stools with increased frequency, fluidity, and weight, or with increased stool water excretion.

22. Diarrhea (cont'd) Acute diarrhea
Most cases of acute, watery diarrhea are caused by viruses (viral gastroenteritis)
The most common ones in children are rotavirus and in adults are norovirus (this is sometimes called “cruise ship diarrhea” due to well publicized epidemics)
Last from 3 days to 2 weeks

23. Antidiarrheals: Mechanism of Action
Adsorbents
Coat the walls of the GI tract
Bind to the causative bacteria or toxin, which is then eliminated through the stool
Examples: bismuth subsalicylate (Pepto-Bismol), kaolin-pectin, activated charcoal, attapulgite (Kaopectate)

24. Cathartics
Laxatives make defecation easier . Purgatives cause bowels to evacuate everything from them. Cathartics make urgency to defecate sooner
In medicine, a cathartic is a substance that accelerates defecation. This is in contrast to a laxative, which is a substance which eases defecation, usually by softening faeces. It is possible for a substance to be both a laxative and a cathartic

25. laxative effect
Laxative should only be used for short term therapy as prolonged use may lead to loss of spontaneous bowl rhythm upon which normal evacuation depends, causing patient to become dependent on laxatives, the so called laxative effect.
Four types of laxatives are known:
Stimulants
Bulk forming
Emollient
Saline cathartics

26. Stimulants act by local irritation on the intestinal tract which increase peristaltic activity.
They include phenolphthalein, aloin, cascara extract, rhubarb extract, senna extract, podophyllin, castor oil, bisacodyl, calomel etc.
Bulk forming laxatives are made from cellulose, sodium carboxyl methyl cellulose and karaya gum

27. Continue…
The emollient laxatives act either as lubricants facilitating the passage of compacted faecal material or as stool softeners. e.g mineral oil, d-octyl sodium sulfosuccinate, an anionic surface active agent.
Saline cathartics act by increasing the osmotic load of the GIT. They are salts of poorly absorbable anions –(biphosphate), (phosphate), sulphates, tartarates, and soluble magnesium salt.

28. Saline cathartics
Saline cathartics or purgatives are agents that quicken and increase evacuation from the GI tract.
Laxatives are mild cathartics. Cathartics are used:
to ease defecation in patients with painful hemorrhoids or other rectal disorders and to avoid excessive straining and concurrent increase in abdominal pressure in patients with hernias or to relieve acute constipation

29. Magnesium Sulphate
I.P. limit: It contains not less than 99.0% and not more than 100.5% of magnesium sulphate calculated with reference to dried substance.
Properties: It forms colorless prismatic crystals. It dissolves in water, is practically insoluble in alcohol.
Preparation:
1) It can be prepared by neutralizing hot dilute sulphuric acid with magnesium or its oxides or carbonate. The solution is filtered; the filtrate is concentrated and recrystallized with H2O
2) On commercial scale it is manufactured by reacting sulphuric with dolomite. Magnesium sulphate so formed is dissolved in the solution and the sparingly soluble calcium sulphate is deposited.

30. Test for Identification:
For magnesium: To solution of sample add dilute nitric acid solution a white precipitate is produced that is redissolved by adding 1ml of 2M ammonium chloride, add 0.25M disodium hydrogen phosphate a white crystalline precipitate is produced.
For sulphate: To 5ml of sample solution add 1ml of dilute HCl and 1ml barium chloride solution white precipitate. Add 1ml of iodine solution to the suspension, the suspension remains yellow (distinction from sulphites and dithionites) but decolorizes on adding stannous chloride (distinction from iodates).
Assay: Weigh accurately about 6.3gm of sample dissolve in 50ml of water, add 10ml of strong ammonia ammonium chloride solution and titrate with 0.05M disodium EDTA using 0.1gm of moderate black II mixture as indicator until blue color is obtained. Each ml of 0.05M disodium EDTA≡ gm of MgSO4
Uses: It is used as osmotic laxative, in treatment of electrolyte deficiency, in treatment of cholecystitis, sea sickness, hypertension etc.

31. Aluminum hydroxide: Uses
This medication is used to treat the symptoms of too much stomach acid such as stomach upset, heartburn, and acid indigestion. Aluminum hydroxide is an antacid that works quickly to lower the acid in the stomach. Liquid antacids usually work faster/better than tablets or capsules.
This medication works only on existing acid in the stomach. It does not prevent acid production. It may be used alone or with other medications that lower acid production (e.g., H2 blockers such as cimetidine/ranitidine and proton pump inhibitors such as omeprazole).

32. MAJOR INTRA AND EXTRA CELLULAR ELECTROLYTES
An electrolyte is any substance that dissociates into ions .
Ions can be positively charged (cations) or negatively charged (anions) in aqueous solution.
The major electrolytes found in the human body are:
Sodium (Na+),
Chloride (Cl- )
Potassium (K+),
Phosphate (HPO4--)
Calcium (Ca++)
Sulfate (SO4--)
Magnesium (Mg++)
Bicarbonate (HCO3- )

33. electrolytes

34. Continue..
Interstitial fluid and blood plasma are similar in their electrolyte make up. Na + and Cl- being the major electrolytes. In the intracellular fluid, K+ and HPO4- are the major electrolytes.
Physiological role of Sodium
This plays a crucial role in the excitability of muscles and neurones. It is also of crucial importance in regulating fluid balance in the body.
Sodium levels are extremely closely regulated by kidney function.
Sodium is easily filtered in the glomerular portion of the kidneys and most of it is reabsorbed in the kidney tubules.
Major factors that control the GFR include the blood pressure at the glomerulus and the stimulation of renal arteriole by the sympathetic nervous system.
The amount of sodium reabsorbed in the proximal convoluted tubule remains almost constantly at around 67%.

35. Physiological role of Potassium
Because water has a close chemical affinity for sodium, it will follow that more water is reabsorbed in the kidney as well and this will put up the BP to a normal level.
Physiological role of Potassium
Potassium is the major cation of intracellular fluid. Concentration within the cells is 28x that of the extra cellular fluids. As with sodium it is extremely important in the correct functioning of excitable cells such as muscles, neurones, sensory receptors etc.
It is also importantly involved in the regulation of fluid levels within the cell and in maintaining the correct pH balance within the body.

36. Physiological role of Calcium
Calcium is found mainly in the extracellular fluids whilst phosphorous is found mostly in the intracellular fluids. Both are important in the maintenance of healthy bone and teeth.
Calcium is also important in the transmission of nerve impulses across synapses, the clotting of blood and the contraction of muscles. If the levels of calcium fall below normal level both muscles and nerves become more excitable.

37. Physiological role of Phosphate
Phosphate is required in the synthesis of nucleic acids and high-energy compounds such as ATP. It is also important in the maintenance of pH balance.

38. Physiological role of Magnesium
Most magnesium is found in the intracellular fluid and in bone. Within cells, magnesium functions in the sodium-potassium pump and as an aid to the action of enzymes.
It plays a role in muscle contraction, action potential conduction, and bone and teeth production.
Aldosterone controls magnesium concentrations in the extracellular fluid. Low Mg++ levels result in an increased aldosterone secretion, and the aldosterone increases Mg++ reabsorption by the kidneys.

39. Physiological role of Chloride
Chloride (Cl-) is the most plentiful extracellular anion with an extracellular concentration 26 times that of its intracellular concentration.
Chloride ions are able to diffuse easily across plasma membranes and their transport is closely linked to sodium movement, which also explains the indirect role of aldosterone in chlorine regulation.
When sodium is reabsorbed, chlorine follows passively. It helps to regulate osmotic pressure differences between fluid compartments and is essential in pH balance.
The chloride shift within the blood helps to move bicarbonate ions out of the red blood cells and into the plasma for transport.
In the gastric mucosa, chlorine and hydrogen combine to form hydrochloric acid

40. Physiological role of Bicarbonate
Bicarbonate is alkaline, and a vital component of the pH buffering system of the human body (maintaining acid-base homeostasis).
70 to 75 percent of CO2 in the body is converted into carbonic acid (H2CO3), which can quickly turn into bicarbonate (HCO3−).
With carbonic acid as the central intermediate species, bicarbonate – in conjunction with water, hydrogen ions, and carbon dioxide – forms this buffering system, which is maintained at the volatile equilibrium required to provide prompt resistance to drastic pH changes in both the acidic and basic directions.
This is especially important for protecting tissues of the central nervous system, where pH changes too far outside of the normal range in either direction could prove disastrous (causing great damage).
Bicarbonate also acts to regulate pH in the small intestine. It is released from the pancreas in response to the hormone secretin to neutralize the acidic chyme entering the duodenum from the stomach.

41. Thank you