Diarrhoea and Constipation By Priyanca Patel

What is Constipation? Infrequent bowel movements due to increased transit time or pelvic dysfunction What factors could cause constipation? Age Physiology Medication Opioids Anticholinergics TCAs CCBs Diet Illness or disorder Hormonal

What treatment options are available for constipation? Lifestyle: Changes in diet and exercise habits Purgatives: accelerate transit of faeces through the intestine

What are the 4 main classes of purgatives?  F aecal softeners  O smotic laxatives  B ulk laxatives  S timulant laxatives

 Alter fecal consistency  Surface acting compounds  Act slowly (3-5 days) to keep stools soft  Used for constipation and fissures/ piles  Docusate - softens faeces  Mineral oils - lubrication Fecal Softeners

Osmotic Laxatives  Poorly absorbed solutes  Maintain an increased volume of fluid in GI tract, therefore accelerating transit time  Saline purgatives - Mg sulphate and Mg hydroxide used for bowel prep prior to procedure as rapidly acting  Lactulose - semi synthetic disaccharide (fructose and glucose)  2 poorly absorbed monosaccharaides (by colonic bacteria)  fermentation yields lactic acid + acetic acid. Acts in 1-3 days and can be prescribed alongside opioids

Bulk Laxatives  Polysaccharide polymers that are NOT broken down by the normal process of digestion  Retain water in the GI lumen, softening and increasing fecal bulk and promote motility  Eg. Methylcellulose and plant gums such as bran, agar or ispaghula husk  Faster acting days  Good first choice for constipation and IBS

Stimulant laxatives- Senna + Bisacodyl  Contains a glycoside which passes unchanged into the colon  Bacteria act upon it to release free anthrancene derivatives which have a direct effect upon the myenteric plexus  Usually taken at night and takes around 8hrs to work  Short term use is safe but abuse  melanosis coli and/or cathartic colon  Bisacodyl usually given as a suppository  Stimulates rectal mucosa  mass movements and defecation in 15-30mins

What is diarrhoea? Frequent, watery, loose bowel movements involving increased GI motility and secretion and decreased absorption of water What factors could cause diarrhoea? Infectious agents Toxins Anxiety Drugs Antibiotics PPIs Antidepressants

What are the 4 main types of diarrhoea?  M otility-related diarrhoea  O smotic diarrhoea  I nflammatory diarrhoea  S ecretory diarrhoea

What are the main treatments for diarrhoea?  Maintenance of fluid/ electrolyte balance (ESP. Na + and K + )  Anti-infective agents  Anti-diarrheal agents

Anti-motility agents  Eg. Immodium or diocalm  Opioids: codeine + loperamide  Loperamide has relatively selective action on GI tract – mu opioid receptors in the myenteric plexus  Increases tone and rhythmic contractions of colon whilst diminishing propulsive activity