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Laxative and Antidiarrheal Agents

Laxative and Antidiarrheal Agents. By Clare Shalders/ GoTafe/ 2007. Actions of Drugs Used to Affect Motor Activity of the GI Tract. Speed up or improve movement of intestinal contents when movement becomes slow or sluggish (constipation)

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Laxative and Antidiarrheal Agents

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  1. Laxative and Antidiarrheal Agents By Clare Shalders/ GoTafe/ 2007 CSHALDERS/GOTAFE/2008

  2. Actions of Drugs Used to Affect Motor Activity of the GI Tract Speed up or improve movement of intestinal contents when movement becomes slow or sluggish (constipation) Increase the tone of the GI tract and stimulate motility throughout the system Decrease movement along the GI tract when rapid movement decreases the time for absorption of nutrients (diarrhea) CSHALDERS/GOTAFE/2008

  3. Site of Action of Drugs Affecting GI Motility CSHALDERS/GOTAFE/2008

  4. Types of Laxatives • Chemical stimulants • Chemically irritate the lining of the GI tract • Bulk stimulants • Cause the fecal matter to increase in bulk, natural plant gums. Stimulate peristalsis by increasing bulk in stool through absorption of water in the colon • Lubricants • Help the intestinal contents move more smoothly CSHALDERS/GOTAFE/2008

  5. Stimulant Stimulants • Senna (Senokot): Reliable drug, similar to cascara (OTC) Produces bowel action in 6-12 hours • Castor oil (Neoloid): Old standby for thorough evacuation of the intestine • Bisacodyl (Dulcolax): Very popular OTC laxative; Enteric coated to dissolve in small intestine and produces stimulating effect on colon. Can irritate stomach hence enteric coated. Evacuation 6-12 hours after oral and 15-60 mins supp CSHALDERS/GOTAFE/2008

  6. Feacal Softeners • Ducosate: Faecal softening agent, detergent like properties acts by holding water to the feacal matter, thus rendering it softer and easier to pass • Poloxamer: Coloxyl. Also act on intestinal wall to inhibit water reabsorption, these are used to ease bowel movements and work over several days. CSHALDERS/GOTAFE/2008

  7. Types of Osmotic Laxatives • Magnesium sulfate (Epsom Salts) • Sodium phosphate, sodium salts • Glycerol • Lactulose (Chronulac) • Sorbitol • Psyllium (Metamucil) CSHALDERS/GOTAFE/2008

  8. Osmotic Laxatives • Contents are hypertonic, causing water to be retained and if the osmotic pressure is great enough, can pull water from the gut capillaries back in to the bowel lumen. Leading to a stimulation in the defecation process CSHALDERS/GOTAFE/2008

  9. Types of Lubricating Laxatives • Docusate, liquid paraffin. • Has a detergent action on the surface of the intestinal bolus, making a softer stool • Glycerin (Sani-Supp) • Hyperosmolar laxative used to gently evacuate the rectum without systemic effects higher in the GI tract • Mineral oil (Agoral Plain) • Forms a slippery coat on the contents of the intestinal tract CSHALDERS/GOTAFE/2008

  10. Lubricants • Action is purely physical, relatively little absorption occurring • Their action is lubrication CSHALDERS/GOTAFE/2008

  11. Lubricants • Adverse Effects • Liquid paraffin can interfere with absorption of fat soluble vitamins, Vit A D and K • It can accumulate in the intestinal mucosa resulting in paraffinomata- polyp like growths CSHALDERS/GOTAFE/2008

  12. Lubricants • If the paraffin finds its way into the general circulation or small amounts leak through the epiglottis when swallowed, accumulation in the lungs can develop- resulting in lipoid pnuemonia • Clients should take liquid paraffin preparations at least half an hour before lying down CSHALDERS/GOTAFE/2008

  13. Indications for the Use of Laxatives • Short-term relief of constipation • Prevent straining when it is clinically undesirable • Evacuate the bowel for diagnostic procedures • Remove ingested poisons from the lower GI tract • As an adjunct in athelmintic therapy ( T of worms CSHALDERS/GOTAFE/2008

  14. Focus on the Prototype Chemical Stimulant: Castor Oil • Indications:Evacuate the bowel for diagnostic procedures; remove ingested poisons from the lower GI tract; adjunct in anthelmintic therapy • Actions:Directly stimulates the nerve plexus in the intestinal wall, causing increased movement and the stimulation of local reflexes • Pharmacokinetics:Not absorbed systemically • Not absorbed systemically CSHALDERS/GOTAFE/2008

  15. Focus on the Prototype Bulk Laxative: Magnesium Citrate • Indications:Short-term relief of constipation; prevent straining; evacuate the bowel for diagnostic procedures; remove ingested poisons; adjunct in anthelmintic therapy • Actions:Increases motility of the GI tract by increasing the fluid in intestinal contents; enlarges bulk; stimulates local stretch receptors; activates local activity • Pharmacokinetics:Not absorbed systemically Not absorbed systemically CSHALDERS/GOTAFE/2008

  16. Focus on the Prototype Lubricant: Mineral Oil • Indications:Short-term relief of constipation; prevent straining; remove ingested poisons; an adjunct in anthelmintic (treatment of worms) therapy • Actions:Forms a slippery coat on the contents of the intestinal tract; less water is absorbed out of the bolus; bolus is less likely to become hard or impacted • Pharmacokinetics:Not absorbed systemically • Not absorbed systemically CSHALDERS/GOTAFE/2008

  17. Types of Gastrointestinal Stimulants • Dexpanthenol (Ilopan) • Increases acetylcholine levels and stimulates the parasympathetic system • Metoclopramide (Reglan) • Blocks dopamine receptors and makes the GI cells more sensitive to acetylcholine • Leads to increased GI activity and rapid movement of food through the upper GI tract CSHALDERS/GOTAFE/2008

  18. Focus on the GI Stimulant Prototype: Metoclopramide • Indications:Acute and chronic diabetic gastroparesis; gastroesophageal reflux disorder; postoperative nausea and vomiting; small bowel intubation; gastric emptying; intestinal transit of barium • Actions:Stimulates movement of the upper GI tract without stimulating gastric, pancreatic, or biliary secretions; sensitizes tissues to acetylcholine effects • Routes: Oral, IM, IV • metabolized in the liver; excreted in urine CSHALDERS/GOTAFE/2008

  19. Types of Antidiarrheal Drugs • Bismuth subsalicylate (Pepto-Bismol): Coats the lining of the GI tract and soothes irritation stimulating local reflexes to cause excessive GI activity and diarrhea • Loperamide (Imodium): Has a direct effect on the muscle layers of the GI tract; slows peristalsis and allows increased time for absorption of fluid and electrolytes • Opium derivatives (paregoric): Stimulates spasm within the GI tract, stops peristalsis and diarrhea CSHALDERS/GOTAFE/2008

  20. Antidiarroeals • Apart from antibiotics drugs used in the treatment effect only the symptoms and not the underlying cause • Drugs used for non specific diarrhoea usually slow gastrointestinal motility or help absorb the excessive fluid in the colon CSHALDERS/GOTAFE/2008

  21. Antidiarrhoeals • Antimuscarinic drugs can be used to treat colicky pain, but have no effect on stool frequency • Antibiotics only used if the cause is known i.e.: Salmonella, Shigella, Campylobacter, E Coli • Antibiotic of choice: antibacterial agent doxycycline or ciprofloxacin CSHALDERS/GOTAFE/2008

  22. Functions of Antidiarrheal Drugs • Soothe irritation to the intestinal wall • Block GI muscle activity to decrease movement • Affect CNS activity to cause GI spasm and stop movement • Relief of symptoms and fluid and electrolyte loss • Many OTC antidiarrhoeal drugs, contain limited amounts of opiods (codeine, loperamide) aluminium hydroxide, kaolin and pectin (hyoscine and atropine) CSHALDERS/GOTAFE/2008

  23. Antidiarrhoeals • Precautions • Care should be taken when using antidiarrhoeals if the cause of the diarrhoea is bacterial as this allows the bacterial toxin to remain in the body. • Constipation can result from excess use CSHALDERS/GOTAFE/2008

  24. Non Specific Antidiarrhoeal Drugs • Most narcotic analgesics act as opiod receptors in the GI tract • This stimulus increases mixing movements of the gut and therefore decreases peristaltic movements. • Eg Diphenoxylate/Lopermaide • Adverse Effects • Constipation, nausea abdominal cramping CSHALDERS/GOTAFE/2008

  25. Absorbents • Act by coating the intestinal mucosa, absorbing the bacteria or toxins causing the diarrhoea and passing them out with the stools • Examples include aluminium hydroxide (Kaomagna) and kaolin and pectin (Kaopectate) • General initial higher dose then lower after each bowel movement • Caution if other meds given concurrently, they can bind the other drugs CSHALDERS/GOTAFE/2008

  26. Absorbents • Adverse Effects • Kaolin and pectin can interfere with absorption of other drug • Can interfere with estimation of fluid loss CSHALDERS/GOTAFE/2008

  27. Peppermint oil • Causes relaxation of the sphincters • Enteric coated as relaxation of the cardiac oesophageal sphincter can lead to reflux oesophagitis if it released in the stomach CSHALDERS/GOTAFE/2008

  28. Opiod Antidiarrhoeals • Loperamide are OTC opiods that activate opiod receptors in the gut wall, resulting in a reduction in secretions and inhibition of propulsive movements in the gut. • This slows the passage of intestinal contents and allows reabsorption of water and electrolytes, reducing stool frequency • Indicated for short term treatment • Lomotil can produce adverse reactions of dizziness, dry mouth and blurred vision CSHALDERS/GOTAFE/2008

  29. Inflammatory Bowel Disease • Includes ulcerative colitis and crohns disease • Includes drug therapy, dietary and lifestyle factors • Current therapy corticosteroids and sulphazine,mesalazine and olsalazine and immunosuppressant such as cyclosporin and methotraxate • Infliximab a new humanised antibody that targets tumour necrossis factor alpha, for crohns disease CSHALDERS/GOTAFE/2008

  30. Inflammatory Bowel Disease • Corticosteroids • Prednisolone (as suppositories and retention enemas) • Budenoside as enteric coated tablets used in Crohns disease • Others include prednisolone, hydrocortisone and methylprednisolone CSHALDERS/GOTAFE/2008

  31. Inlammatory Bowel Disease • (5-ASA) • Sulphasalazine effective when metabolised in the intestine in two moieties. The two need to be combined so that hydrolysis of the sulphasalazine takes place in the colon, where most needed. CSHALDERS/GOTAFE/2008

  32. Inflammatory Bowel Disease • Mesalazine has been used on its own as an enema • A prodrug osmesalazine, balsalazide is now released in Australia • Clinical trials suggest may produce better symptom relief CSHALDERS/GOTAFE/2008

  33. Inflammatory Bowel Disease • Adverse Effects • Heamatological disorders, nausea and abdominal pain • Sulphasalazine can cause reversible male infertility by lowering sperm counts CSHALDERS/GOTAFE/2008

  34. Inflammatory Bowel Disease • Immunosuppresants • Azathioprine,Mercaptopurine, Methotrexate, and Cyclosporin • Infiximab a monoclonal antibody useful in severe Chrons disease • Are of use when clients cannot be weaned off corticosteroids, assist in inducing and maintaining remission of symptoms CSHALDERS/GOTAFE/2008

  35. Antispasmodics • Used to control smooth muscle spasm • Most are antimuscarinic drugs which block muscarinic receptors • Eg Mebeverine/ Tegaserod CSHALDERS/GOTAFE/2008

  36. Gallstone Dissolution • Ursodeoxycholic Acid • Naturally occurring bile acid, which induces cholesterol containing gallstones to dissolve. • May eventually cause the stone to disappear, only useful if stones are small CSHALDERS/GOTAFE/2008

  37. Gallstone Dissolution • Adverse Effects • Diarrhoea in half of all clients • Hepatotoxicity, recommended periodic liver function tests • Cost and length of treatment • Nausea and vomiting reduced if taken with food CSHALDERS/GOTAFE/2008

  38. Haemorrhoids • Varicose veins in the anal canal • Local anaesthetics, lignocaine,benzocaine, cinchocaine commonly used • Excessive use can result in systemic effects CSHALDERS/GOTAFE/2008

  39. Haemorrhoids • Corticosteroids in anal preparations will help suppress inflammation, itching and swelling • Excessive use leads to systemic effects • Commonly used agents hydrocortisone,prednisolone and fluocortolone CSHALDERS/GOTAFE/2008

  40. Haemorrhoids • Antispetic agents such as cetylpyridium chloride. Cetrimide, and chlorhexidine may inhibit microbial growth of the lesion • Zinc and aluminium precipitate cell surface protiens and thus reduce swelling. • Witch Hazel topically cleanse and soothe the area CSHALDERS/GOTAFE/2008

  41. Haemorrhoids • Clinical considerations • High fibre diet • Topical anorectal agents short term use only • Local anesthetics can cause sensitisation of the perianal skin • Corticosteroids may aggravate localised infection and cause skin atrophy CSHALDERS/GOTAFE/2008

  42. Rectal Administration • Suppositories • Advantages • The unconscious patient • Nauseous or vomiting client • Difficulty swallowing CSHALDERS/GOTAFE/2008

  43. Suppositories • Disadvantages • Can cause rectal irritation • Client education required • Always inserted in left lateral position to avoid perforation of the rectum • Melt at body heat CSHALDERS/GOTAFE/2008

  44. Enemas • Liquid preparations for rectal administration • For topical or systemic use they are termed retention enemas, and are hypotonic solutions and will be taken up in the body with rectal and colonic mucousa CSHALDERS/GOTAFE/2008

  45. Enemas • When used a laxatives,enemas are hypertonic to cause an outward flow of water from the body into the distal portion of the digestive system and thus promote defeacation CSHALDERS/GOTAFE/2008

  46. Enemas: Insertion • Client left lateral position • Wear disposable gloves • Lubricate tip • Administer medication slowly • Ask client to gently hold buttocks together for as long as possible CSHALDERS/GOTAFE/2008

  47. Gallstone Dissolution • Ursodeoxycholic acid naturally occurring bile acid, induces cholesterol containing gallstones to dissolve • Adverse effects • Diarrhea • Cost and length of treatment CSHALDERS/GOTAFE/2008

  48. Haemorrhoidal treatment • Only treatment is in the relief of symptoms • Local aneasthetics are in treatments to relieve the pain lignocaine, benzocaine and cinchocaine • Excessive usage can result in systemic effects CSHALDERS/GOTAFE/2008

  49. Haemorrhoidal treatment • Corticosteroids in anal preparation will help to suppress inflammation, itching and swelling • Hydrocortisone, prednisolone • Antiseptic agents may be incorporated in anal preparations to inhibit microbial growth CSHALDERS/GOTAFE/2008

  50. Haemorrhoidal treatment • Also used to treat anal fissure • Glyceryl trinitrate relaxes the smooth muscle, improves blood supply and allows healing to proceed without the need for surgery CSHALDERS/GOTAFE/2008

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