Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheals and Laxatives Drugs Affecting the Gastrointestinal System

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Diarrhea Abnormal frequent passage of loose stoolsAbnormal frequent passage of loose stoolsor Abnormal passage of stools with increased frequency, fluidity, and weight, or with increased stool water excretionAbnormal passage of stools with increased frequency, fluidity, and weight, or with increased stool water excretion

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Diarrhea Acute Diarrhea Sudden onset in a previously healthy personSudden onset in a previously healthy person Lasts from 3 days to 2 weeksLasts from 3 days to 2 weeks Self-limitingSelf-limiting Resolves without sequelaeResolves without sequelae

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Diarrhea Chronic Diarrhea Lasts for over 3 to 4 weeksLasts for over 3 to 4 weeks Associated with recurring passage of diarrheal stools, fever, loss of appetite, nausea, vomiting, weight loss, and chronic weaknessAssociated with recurring passage of diarrheal stools, fever, loss of appetite, nausea, vomiting, weight loss, and chronic weakness

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Causes of Diarrhea Acute DiarrheaChronic Diarrhea BacteriaTumors ViralDiabetes Drug-inducedAddison’s disease hyperthyroidism NutritionalIrritable bowel syndrome Protozoal

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheals: Mechanism of Action Adsorbents Coat the walls of the GI tractCoat the walls of the GI tract Bind to the causative bacteria or toxin, which are then eliminated through the stoolBind to the causative bacteria or toxin, which are then eliminated through the stool Examples: bismuth subsalicylate (Pepto-Bismol), kaolin-pectin, activated charcoal, attapulgite (Kaopectate)

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheals: Mechanism of Action Anticholinergics Decrease intestinal muscle tone and peristalsis of GI tractDecrease intestinal muscle tone and peristalsis of GI tract Result: slowing the movement of fecal matter through the GI tractResult: slowing the movement of fecal matter through the GI tract Examples: belladonna alkaloids (Donnatal), atropine, hyoscyamine

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheals: Mechanism of Action Intestinal Flora Modifiers Bacterial cultures of Lactobacillus organisms work by:Bacterial cultures of Lactobacillus organisms work by: –Supplying missing bacteria to the GI tract –Suppressing the growth of diarrhea-causing bacteria Examples: Lactobacillus acidophilus (Lactinex)

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheals: Mechanism of Action Opiates Decrease bowel motility and relieve rectal spasmsDecrease bowel motility and relieve rectal spasms Decrease transit time through the bowel, allowing more time for water and electrolytes to be absorbedDecrease transit time through the bowel, allowing more time for water and electrolytes to be absorbed Examples: paregoric, opium tincture, codeine, loperamide, diphenoxylate

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheal Agents: Side Effects Anticholinergics Urinary retention, hesitancy, impotenceUrinary retention, hesitancy, impotence Headache, dizziness, confusion, anxiety, drowsinessHeadache, dizziness, confusion, anxiety, drowsiness Dry skin, rash, flushingDry skin, rash, flushing Blurred vision, photophobia, increased intraocular pressureBlurred vision, photophobia, increased intraocular pressure

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheal Agents: Side Effects Opiates Drowsiness, sedation, dizziness, lethargyDrowsiness, sedation, dizziness, lethargy Nausea, vomiting, anorexia, constipationNausea, vomiting, anorexia, constipation Respiratory depressionRespiratory depression Bradycardia, palpitations, hypotensionBradycardia, palpitations, hypotension Urinary retentionUrinary retention Flushing, rash, urticariaFlushing, rash, urticaria

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Antidiarrheal Agents: Interactions Adsorbents decrease the absorption of many agents, including digoxin, clindamycin, quinidine, and hypoglycemic agentsAdsorbents decrease the absorption of many agents, including digoxin, clindamycin, quinidine, and hypoglycemic agents Adsorbents cause increased bleeding times when given with anticoagulantsAdsorbents cause increased bleeding times when given with anticoagulants Antacids can decrease effects of anticholinergic antidiarrheal agentsAntacids can decrease effects of anticholinergic antidiarrheal agents

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. LAXATIVES

Constipation Abnormally infrequent and difficult passage of feces through the lower GI tract.Abnormally infrequent and difficult passage of feces through the lower GI tract. Symptom, not a diseaseSymptom, not a disease Disorder of movement through the colon and/or rectumDisorder of movement through the colon and/or rectum Can be caused by a variety of diseases or drugsCan be caused by a variety of diseases or drugs

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Causes of Constipation Metabolic and endocrine disorders Diabetes, hypothyroidism, pregnancyDiabetes, hypothyroidism, pregnancyNeurogenic Autonomic neuropathy, multiple sclerosis, spinal cord lesions, Parkinson’s disease, CVAAutonomic neuropathy, multiple sclerosis, spinal cord lesions, Parkinson’s disease, CVA Adverse drug effects Analgesics, anticholinergics, iron supplements, opiates, aluminum antacids, calcium antacidsAnalgesics, anticholinergics, iron supplements, opiates, aluminum antacids, calcium antacids

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Causes of Constipation Lifestyle Poor bowel movement habits: voluntary refusal to defecate resulting in constipationPoor bowel movement habits: voluntary refusal to defecate resulting in constipation Diet: poor fluid intake and/or low-residue (roughage) diet, or excessive consumption of dairy productsDiet: poor fluid intake and/or low-residue (roughage) diet, or excessive consumption of dairy products Physical inactivityPhysical inactivity Psychological factors: stress, anxiety, hypochondriaPsychological factors: stress, anxiety, hypochondria

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Mechanisms of Action Bulk-formingBulk-forming EmollientEmollient HyperosmoticHyperosmotic SalineSaline StimulantStimulant

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Mechanism of Action Bulk-Forming High fiberHigh fiber Absorbs water to increase bulkAbsorbs water to increase bulk Distends bowel to initiate reflex bowel activityDistends bowel to initiate reflex bowel activity Examples: psyllium (Metamucil), methylcellulose (Citrucel), polycarbophil

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Mechanism of Action Emollient Stool softeners and lubricantsStool softeners and lubricants Promote more water and fat in the stoolsPromote more water and fat in the stools Lubricate the fecal material and intestinal wallsLubricate the fecal material and intestinal walls Examples:Stool softeners: docusate salts (Colace, Surfak) Lubricants: mineral oil

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Mechanism of Action Hyperosmotic Increase fecal water contentIncrease fecal water content Result: bowel distention, increased peristalsis, and evacuationResult: bowel distention, increased peristalsis, and evacuation Examples:polyethylene glycol (GoLYTELY), sorbitol, glycerin, lactulose (Chronulac)

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Mechanism of Action Saline Increase osmotic pressure within the intestinal tract, causing more water to enter the intestinesIncrease osmotic pressure within the intestinal tract, causing more water to enter the intestines Result: bowel distention, increased peristalsis, and evacuationResult: bowel distention, increased peristalsis, and evacuation Examples:magnesium sulfate (Epsom salts) magnesium hydroxide (MOM), magnesium citrate sodium phosphate (Fleet Phospho-Soda)

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Mechanism of Action Stimulant Increases peristalsis via intestinal nerve stimulationIncreases peristalsis via intestinal nerve stimulation Examples:castor oil, senna, cascara, bisacodyl

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Therapeutic Uses Laxative GroupUse Bulk-formingAcute and chronic constipation Irritable bowel syndrome Diverticulosis EmollientAcute and chronic constipation Softening of fecal impaction Facilitation of BMs in anorectal conditions

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Therapeutic Uses Laxative GroupUse HyperosmoticChronic constipation Diagnostic and surgical preps SalineConstipation Diagnostic and surgical preps Removal of helminths and parasites

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Therapeutic Uses Laxative GroupUse StimulantAcute constipation Diagnostic and surgical bowel preps

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Therapeutic Uses Laxative GroupUse Bulk-formingImpaction and fluid overload EmollientSkin rashes Decreased absorption of vitamins HyperosmoticAbdominal bloating, rectal irritation

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Therapeutic Uses Laxative GroupUse SalineMagnesium toxicity (with renal insufficiency), cramping, diarrhea, increased thirst StimulantNutrient malabsorption, skin rashes, gastric irritation, rectal irritation

Copyright © 2002, 1998, Elsevier Science (USA). All rights reserved. Laxatives: Side Effects All laxatives can cause electrolyte imbalances!!!All laxatives can cause electrolyte imbalances!!!