Cathartics

definition classification and compounds

1. Saline cathartics By Dr.N.Gopinathan M.Pharm Ph.D Assistant Professor Faculty of Pharmacy Sri Ramachandra Medical college and Research institute ( Deemed University) Chennai, Tamilnadu India.

2. Definition Drugs that relieve constipation and promote defecation. It is otherwise called as laxatives or purgatives. Constipation is delayed passage of faeces Presence of hard dehydrated fecal matter in the rectum. Habitual use of purgatives. Presence of haemorrhoids and fissures

3. Constipation is relieved by non therapeutic measures like increasing the fibre content of daily diet intake or increase daily fluid intake. If it fails the laxatives and purgatives are used. The intensity of their action depends on dose. Laxatives eliminates soft semisolid stool and the purgative lead to watery evacuation.

4. The order of effectiveness is described as follows Aperients – to smooth and soft Evacuant – to empty Purgative – to clean Catharatic – to completely clean

5. Types of laxative Bulk forming laxatives Osmotic laxatives Lubricants laxatives Surfactant laxatives

6. Bulk forming laxatives It acts on intestinal luminal Hydrophilic Indigestible vegetable fibres which stimulate peristalsis . Peristalsis produce defecation reflexes by increasing the fecal bulk due to their water absorbing and retaining capacity.

7. Bulk forming laxatives Eg wheat bran. Isphagula , carboxy methyl cellulose Administered with plenty of water. Side effect : Bacterial digestion of vegetable fibres within the colon may leads to abdominal discomfort.

8. Osmotic diuretic Non absorbable Indigestible disaccharide. Osmotic action Eg Sorbitol and lactulose . Dose: 10 g twice daily with plenty of water. Side effect: Lead to flatulence, nausea and cramps.

9. Lubricant laxatives Pharmacologically inert mineral oils. It acts on intestinal lumen. It is fecal lubricants and stool softener by decreasing the water absorption from the stools. Eg liquid paraffin 15-30ml / day at bed time Leads to deficiency of fat soluble vitamin.

10. Surfactant laxatives Luminally active laxative. An anionic surfactant which softens the stools by decreasing the surface tension of fluids in the bowel. Sometimes it act as wetting agent for the bowel by emulsifying the colonic contents which facilitates the mixing of water in to fatty substance of feces Eg docusate sodium

11. Purgative

12. It provides semi fluid stool or leads to watery evacuation. These are used for complete cleaning of bowel prior to gastrointestinal endoscopic procedures. To flush out the worms of post bed ridden or post operative patients after the use of anthelmintic drugs

13. Cleaning the bowel before surgery or taking abdominal x-ray Classification Osmotic purgatives Irritant purgatives

14. Osmotic purgative Electrolyte osmotic purgative Saline purgatives

15. Electrolyte osmotic purgative It contains non absorbable PEG It retains water due to its high osmotic nature. It is given along with a balanced isotonic solution which contain sodium chloride, Sodium bi carbonate, sodium sulphate and potassium chloride. It is safer to all patient.

16. Saline purgatives It is soluble inorganic salts which acts by increasing the fecal bulk by retaining water due to its osmotic effect thus increases the peristalsis indirectly. Magnesium salts also releases cholecytokinin which is used to increases the intestinal secretions and peristalsis

17. Common side effect It is given along with plenty of water because being irritant it may induce vomiting. High osmolar property leads to intravascular fluid depletion and electrolyte disturbances. Long term usage should be avoided for hypertensive and cardiac failure patient. Long term use of magnesium for renal failure patient leads to risk of hyper magnesemia .

18. Irritant Purgatives Anthraquinone derivatives – senna , cascara and aloe Oils – Castor oil Organic irritants- Phenolphthalein, bisacodyl All the above stimulate intestinal peristalsis due to their irritant action

19. Common side effect Senna glycoside leads to melanosis coli on long term use. Long term of castor oil use leads to damaging the intestinal mucosa. Bisacodyl leads to hypokalemia .

20. Magnesium hydroxide

21. P reparation It is an aqueous suspension of hydrated magnesium oxide. Light magnesium oxide is mixed with sodium hydroxide solution to get a cream. It is diluted with water; the suspension is poured in thin stream into a solution of magnesium sulphate with constant stirring. The precipitate is allowed to settle .

22. The clear liquid is decanted off. The residue is transferred into a calico filter washed thoroughly with water until it is free from sulphate ions and finally mixed with the required quantity of purified water.

23. In this reaction sodium hydroxide reacts with magnesium sulphate and gives masnesium hydroxide. In the above formula pharmacopoeia permits the use of the following pharmaceutical aid. 0.1% citric acid which is used to minimize the reaction between glass containers and milk of magnesia during storage. Otherwise it imparts bitter taste.

24. 0.5 ml / 1000 ml of volatile oil as a flavouring agent. 0.2% of sodium benzoate 0.125% of methyl paraben as preservative

25. Assay- complexometric Weigh accuratley about 0.1 g dissolve in 20 ml of 2M HCl and dilute to 100 ml with water . To 50ml of this solution add 5 ml of strong ammonia – ammonium chloride buffer and titrate with 0.05M disodium edetate , using 50 mg of mordant black II mixture as indicator.

26. uses Antacid and laxative. Alkaline mouth wash It is used to liberate alkaloids from solution. Dose As Antacid 5-10 ml As laxative 15-30 ml It should not be refrigerated Shake well before use.

27. Magnesium sulphate epsom salt

28. Preparation Laboratory Neutralising of magnesium carbonate with hot sulphuric acid. Filter the solution and concentrate the filtrate to get crystals

29. From Magnesite / Calcined Dolomite The reaction of sulphuric acid with magnesite / calcined dolomite.

30. From brine solution Brine is treated with milk of lime gives magnesium hydroxide. The sulphur di oxide and air is passed through this suspension. Magnesium sulphate crystallised out .

31. Mechanism of action It does not get absorbed from intestine, so it retains sufficient water within the lumen which leads to increase in the hydrostatic pressure of the lumen to promote peristalsis of bowel.

32. Assay - complexometric Weigh accurately about 0.3 g dissolve in 50 ml of water, add 10 ml of strong ammonia – ammonium chloride solution and titrate with 0.05 M disodium edetate using mordant black II as indicator, untill a blue colour is obtained.

33. Use Osmotic laxative Electrolyte replenishers . It is also used in renal impaired patients as laxative.

34. Magnesium Carbonate

35. Preparation of Heavy magnesium carbonate It is preapared by double decomposition of magnesium sulphate and sodium carbonate. 125 parts of magnesium sulphate and 150 parts of sodium carbonate. Dissolved in boiling water separatley . Two solutions are mixed , filtered, washed, evaporated and dried

36. Preparation of light magnesium carbonate 125 parts of magnesium sulphate solution is mixed with 150 parts of sodium carbonate in cold water , heated for 5 minutes then precipitate is collected, washed untill gives a slight reaction for sulphate and dried in an oven.

37. uses Antacid Osmotic laxative Pharmaceutical aid Slow acting antacid. [ during pregnancy and lactation] Cathartic

38. Dose Antacid 300-600 mg Laxative 2-4 g

39. THANK YOU