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Laxative and purgatives

Dr. indrajit Banerje
MBBS, MD
Associate Professor
Chitwan Medical College
Nepal

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Laxative and purgatives

  1. 1. Laxatives & Purgatives Dr. Indrajit Banerjee, MBBS, MD Associate Professor Department of Pharmacology Chitwan Medical College Nepal
  2. 2.  Purgatives & laxatives are drugs that promote evacuation of bowels, used in constipation and dyschezia. Constipation : Delayed passage of faeces through the intestine. Dyschezia: Derangement of defaecation process due to 1. Pain arising from haemorrhoids or fissure 2. Presence of hard dehydrated faecal matter in the rectum 2
  3. 3. Purgative Stronger action resulting in more fluid evacuation Laxative Milder action, elimination of soft but formed stools. Aperients (to get rid off) < Laxatives (to loosen) < Emolient (to smooth and soften) < Evacuant (to empty) < Purgatives (to clean)< Cathartic (to utterly clean) 3
  4. 4. Classification of Drugs 1. Bulk forming Dietary fibre: Bran*, Psyllium, Ispaghula*, Methylcellulose 2. Stool softener Docusates (DOSS)*, Liquid paraffin* 3. Stimulant purgatives (a) Diphenylmethanes Phenolphthalein, Bisacodyl*, Sodium picosulfate 4
  5. 5. (b) Anthraquinones (Emodins) Senna, Cascara sagrada (c) 5-HT4 agonist: Prucalopride (d) Fixed oil: Castor oil 4. Osmotic purgatives Magnesium salts: sulphate*, hydroxide* Sodium salts: sulfate, phosphate Sod. pot. tartrate Lactulose* 5
  6. 6. Laxatives/ Purgatives •Mr Akash is suffering from Inguinal Hernia. •Mr. Gurung suffering from Tape worm infestation is on Niclosomaide. Which drug should be combined along with it? • Mrs. Rita undergoing abdominal X ray • Mr. Ram who is a post MI patient suffering from constipation. • Mr. Alok who is a post MI patient. Which drug can be used for prophylaxis of constipation 6 At the end of this session all of you should be able to address these conditions confidently
  7. 7. LAXATIVES
  8. 8. Laxatives are used 1) To treat constipation 2) To avoid undue straining at defaecation in cases having hernia, haemorrhoids or cardiovascular disease 3) Before or after surgery of any anorectal disease 4) In bedridden patients. Laxatives 8
  9. 9.  Bulk-Forming Laxatives: Wheat bran, Psyllium husk, Ispaghula, Methyl cellulose.  Osmotic Laxatives: Lactulose, Glycerine suppositories  Lubricant Laxatives :Liquid paraffin  Surfactant Laxatives Docusate (Dioctyl sodium sulfosuccinate) 9
  10. 10.  Bulk-Forming Laxatives: Wheat bran consists of 40% dietary fibre It absorbs water in the intestines, swells, increases water content of faeces Stimulate local peristalsis & defecation reflexes by increasing faecal bulk Dose : 20-40 g/ day, acts 1-3 days S/E : Bloating C/I : GIT ulcerations, adhesions, stenosis10
  11. 11.  Osmotic Laxative: Lactulose: It is a semisynthetic disaccharide of fructose and lactose neither digested, nor absorbed in the small intestine- retains water. Broken down by colonic bacteria- osmotically active products Side effects: Flatulence, cramps 11
  12. 12. Dose of 10 g BD with plenty of water, It produces soft formed stools in 1-3 days Lactulose causes reduction of blood NH3 concentration by 25-50% in patients with hepatic Encephalopathy Dose : 20 g TDS 12
  13. 13. Lubricant Laxatives pharmacologically inert mineral, not palative, but can be given in emulsified form or with juices. Liquid paraffin Dose : 15-30 ml/ hs. Latency period: l-3 days Side Effects :  It is not palatable Frequent use leads to the deficiency of fat soluble vitamins Leakage of oil past anal sphincter 13
  14. 14. Forcible administration can lead to aspiration lipid pneumonia. It also delays the healing of enteric fistula. Foreign body granulomas in the intestine 14
  15. 15. Surfactant Laxatives: [STOOL SOFTENER] Dioctyl sodium sulfosuccinate(Docusate) It is an anionic detergent which softens the stool by decreasing the surface tension of fluids in the bowel. It also acts as a wetting agent for the bowel, because by emulsifying the colonic contents it facilitates the penetration of water into faeces 15
  16. 16. Dosage : 100-400 mg/day. Indicated when straining at defaecation is to be avoided Side Effects: Bitter in taste, Nausea, Cramps and abdominal pain. Prolonged use leads to Hepatotoxicity 16
  17. 17. PURGATIVES
  18. 18. Purgatives are used for complete colonic cleansing 1. Prior to gastrointestinal endoscopic procedure 2. To flush out worms after the use of an anthelmintic drug 3. To prepare the bowel before surgery or abdominal X-ray 4. Food/Drug poisoning 5. For post operative or post-Ml bedridden patient 18
  19. 19. Osmotic Purgatives Purgatives lrritant Purgatives I. Osmotic Purgatives: a) Saline purgatives : Magnesium sulfate, Magnesium hydroxide, sodium sulfate, sod. phosphate, sod. pot. tartarate b) Electrolyte osmotic purgative Polyethylene glycol (PEG)- 19
  20. 20. a) Saline purgatives: Mode of Action:  Increase the faecal bulk by retaining water by osmotic effect, thus increasing peristalsis indirectly.  Doses : Mag. Sulfate : 5-15 g. Mag. Hydroxide: 30 ml. Sod. Sulfate : 10-15 g. Sod. phosphate: 6-12 g. Sod. pot. Tartrate : 8-15 g. Dissolved in 200 ml of water & effects come with in 2-3 hrs & Latency period is 1-3 hrs20
  21. 21. Side Effects and Comments:  Should be ingested with enough water  Magnesium salts: Should not be used for prolonged period in patients with renal insufficiency due to the risk of hypermagnesemia.  Sodium salts should be avoided in hypertensives & CHF 21
  22. 22. 22
  23. 23. II. Irritant Purgatives: (a) Anthraquinone group: Senna, Cascara sagrada, and Aloe. (b) Organic irritants: Phenolphthalein, Bisacodyl, Sodium picosulfate. (c) 5 HT4 Agonist: Prucalopride. (d) Oils: Castor oil. 23
  24. 24. Senna, Cascara sagrada, and Aloe.  Plant purgatives contain anthraquinone glycosides [emodins]  Active principle “anthrol” which acts locally or is absorbed into circulation  Acts on the myenteric plexus to increase peristalsis and decrease segmentation  Senna Dose: 12-25 mg hs, effects come with in 6-8 hours, 24
  25. 25. Side Effects:  Produce abdominal cramps & nausea  Senna glycosides are secreted through milk.  Chronic use leads to brown pigmentation of the colon known as "melanosis coli". 25
  26. 26. Bisacodyl: Activated in the intestine by deacetylation  In the colon it irritate the mucosa, produce mild inflammation and secretion Oral Dose : 5-10 mg hs. The effect appears with in 8-10 hrs. Suppositories act with in 20-40 min Side Effects: Abdominal cramps and skin rashes. Higher doses can cause mucosal damage26
  27. 27. Choice of Drugs /Uses: Functional Constipation 1. Spastic constipation Dietary fibre Bulk forming agents taken over weeks. Stimulant purgatives are contraindicated. 2.Atonic constipation (sluggish bowel): Due to old age, debility or laxative abuse Bulk forming agent, Bisacodyl or senna given once or twice a week 27
  28. 28. 2. Bedridden patients (MI, stroke, fractures, postoperative): Prevent- Bulk forming, docusates, lactulose, liquid paraffin. 3. To avoid straining at stools (hernia, cardiovascular disease, eye surgery) and in perianal afflictions (piles, fissure, anal surgery) Bulk forming agents, Docusates, lactulose and liquid paraffin. 28
  29. 29. 4. Preparation of bowel for surgery, colonoscopy, abdominal X-ray Saline purgative, bisacodyl or senna 5. After anthelmintics: Saline purgative or senna 6. Food/ drug poisoning: Saline purgatives 29
  30. 30. 30
  31. 31. All laxatives are contraindicated in: (i) Undiagnosed abdominal pain, colic or vomiting. (ii) Stricture or obstruction in bowel, hypothyroidism, hypercalcaemia, malignancies 31
  32. 32. Do you know which drugs can cause constipation? •Opioids •Anticholinergics •Antiparkinsonian, •Antidepressants and Antihistaminics •Almunium and Calcium groups of Antacids •Oral iron, clonidine, verapamil Laxative abuse 32
  33. 33. Laxatives/ Purgatives •Mr Akash is suffering from Inguinal Hernia. •Mr. Gurung suffering from Tape worm infestation is on Niclosomaide. Which drug should be combined along with it? • Mrs. Rita undergoing abdominal X ray • Mr. Ram who is a post MI patient suffering from constipation. • Mr. Alok who is a post MI patient. Which drug can be used for prophylaxis of constipation 33 At the end of this session all of you should be able to address these conditions confidently
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