Diarrhea And Constipation Flashcards
Drugs altering motility
Anti-spasmodics - decrease smooth muscle tone
Laxatives - accelerate passage
Anti-diarrhoeal drugs - decrease motiity
Pro-kinetics - increase motility of smooth muscle
Dicyclomine
Antimuscarinic
Hyoscine butyl-bromide
Anti-muscarinic
Mebeverine
Anti-muscarinic
Propantheline
Anti-muscarinic
Falvoxate
Antimuscarinic
Clidinium bromide
Anti-muscarinic
Anti-muscarinics indications
Used as anti-spasmodics
- intestinal
- biliary
- genitourinary
Diarrhea mechanisms
- Increased osmotic load - water retention in lumen
- Excessive secretion of electrolytes
- Exudation of protein and fluid from mucosa
- Altered motility - rapid transit and decreased fluid absorption (inflammatory/infectious)
Diarrhea Mx
- Prevent dehydration
- Anti-infective - curative
- Spasmolytic or other antidiarrhoeal (symptomatic)
Loperamide
Anti-motility agent
Diphenoxylate
Antimotility agent
Codeine
Anti-motility agent
Anti-motility agents
-opioid derivatives - inhibits Ach release - decreased peristalsis and increased sphincter tone
Anti-motility agent indications
Traveller’s diarrhea
Adjunct in chronic diarrheal disease
Anti motility agent SE
- minimal
- some BBB crossing
- low incidence of addiction
Avoid in suspected inflammatory diarrhea
- prolonged fever with shigella
- toxic megacolon in pts w. C. difficile (>6cm dilation of transverse colon)
Bismuth subsalicylate
- decreases fluid secretion
- travellers diarrhoea, episodic diarrhea, acute gastroenteritis, H. Pylori eradication
Adsorbents
- adsorbs intestinal toxins and microorganisms
- coats intestinal mucosa
- interferes with abrorbtion of other drugs
Cholestiramine
Adsorbent - Bile acid sequestrant
Kaolin and Pectin
Adsorbent
Methylcellulose
Adsorbent (fermented fibre)
Aluminium hydroxide
Adsorbent
Probiotics indications
- acute diarrhea
- antibiotic associated diarrhea
- infectious diarrhea
Dietary fibre
Laxative - bulk forming
Unfermented fibre attracts H2O and increases stool bulk - distends intestine increasing peristalsis
(fermented fibre attracts stool water - used in diarrhea)
- hydrophilic colloids
- indigestible parts of fruit and veg
- psyllium seeds, bran, ispaghula
Osmotic active agents
Saline laxatives: magnesium citrate - non-absorbable salts
Electrolyte solution laxatives
-polyehtylene glycol
Nondigestible sugars & alcohols
- lactulose - semi-synthetic sugar cannot be hydrolized by intestinal enzymes
- increases osmotic pressure, increase fluid, increase lumen pressure, stimulate evacuation
Docusate sodium/calcium/potassium
Laxative - stool wetting agent
- lowers surface tension of stools - allow mixing
- may take days
Mineral oil
Indigestible
-causes anal leakage and lipid pneumonitis NB
Senna
Stimulant laxative
-induce limited low grade inflammation
Bisacodyl
Stimulant laxative
-induce limited low grade inflammation
Castor oil
- irritant laxative
- stimulates uterine contractions in pregnant
Pro-kinetic agents
- increase intensity of contractions in small intestine without rhythm disruption
- good in diabetics with gastroparesis
Dopamine receptor antagonists
Suppress Ach release
-inhibits motility, reduces LOS tone, reduce intragastric pressure
- metoclopramide
- domperidone
Cisapride
5HT4 agonist - prokinetic agent
-ventricular arrhythmia
Macrolide
Pro-kinetic agent
Only used in diabetics with gastroparesis
