Antidiarrheal and Laxatives Flashcards
Drugs that alter the motility of the gastrointestinal tract include
**Antidiarrheal drugs and antispasmodic drugs:
Decrease motility or decrease smooth muscle tone
Laxatives/Purgatives:
Accelerate the passage of food through the intestine
Acute Diarrhea
Sudden onset
3 days-2 weeks
Causes:
Microbial
Drug-induced
Nutritional
Chronic Diarrhea
-Lasts longer than 3 weeks
-Associated with recurring passage of diarrhea, fever, loss of appetite, nausea, vomiting, weight loss, weakness
Causes:
Tumours, diabetes, hormonal, IBS
Antidiarrheal: Opioids
Opioid receptor activation decreases bowel motility. Increases bowel transit time which allows more time for water and electrolytes to be absorbed
DRUGS:
Loperamide (Imodium)
Poorly absorbed. Poor access to CNS
ADVERSE:
Excessive use can lead to typical opioid drug effects such as drowsiness, sedation, nausea, vomiting, resp depression, urinary retention, flushing
Antidiarrheal: Adsorbents
-Coat wall of GI tract
-Inhibit intestinal secretions
Example: Bismuth subsalicylate and activated charcoal
Bismuth subsalicylate also used for stomach acid symptoms.
ADVERSE: Bismuth can cause constipation and dark stool/tongue
DO NOT give bismuth subsalicylate to children with viral infections - Reye’s syndrome
Antidiarrheal: Anticholinergics
Decrease muscle cramping
DRUG: Atropine
Adverse effects: CNS excitation, dizziness, anxiety, dry mouth, constipation
Laxatives mechanism of actions
Bulk forming
Osmotic
Fecal softener
Stimulant
(DO NOT use in bowel obstruction)
Laxatives: Bulk Forming
High fibre substances
Absorbs water to increase bulk
Distends bowel to initiate bowel activity
Laxatives: Osmotic Laxatives
-Non-absorbable compounds or salt solutions that draw water into intestinal lumen
-Can cause dehydration
Hyperosmotic Compounds
Increase fecal water content.
DRUGS:
Lactulose
Salines: Magnesium hydroxide
Increase osmotic pressure in intestinal tract, causing more water to enter intestines
Laxatives: Fecal Softeners
-Stool softeners and lubricants
-Promote more water and fat in stools
-Lubricate fecal matter and walls
DRUG: Docusate sodium
Laxatives: Stimulant
-Increases peristalsis via intestinal nerve stimulation
-Increase fluid secretion into intestine
DRUG: Senna
Laxatives used to counteract opioid constipation
Stimulants and fecal softener
Client care
Pts should take bulk-forming laxatives with at least 240 ml of water
Long-term laxative use can result in decreased bowel tone and lead to dependency
