Ch. 58 Drugs Affecting GI Motility Flashcards
Define Laxatives
short-term relief of constipation
What do chemical stimulants do?
chemically irritate the lining of the GI tract
what do bulk stimulants do?
cause the fecal matter to increase in bulk
what do lubricants do?
help the intestinal contents move more smoothly
what is the prototype of chemical stimulant
Castor Oil
what is the prototype of bulk stimulant
Magnesium Citrate
what is the prototype of lubricants
Mineral Oil
Mineral Oil: Indications
- short term relief of constipation
- prevent straining when clinically undesirable
- remove ingested poisons from the lower GI tract
- adjunct in anthelmintic therapy when desirable to flush helminths from GI tract
Mineral Oil: Actions
- forms a slippery coat on the contents of the intestinal tract
- less H2O is absorbed out of the bolus = less likely to become hard or impacted
Mineral Oil: Adverse Effects
- diarrhea
- abdominal cramps
- bloating
- perianal irritation
- dizziness
- interference w/ absorption of fat-soluble vitamins
- leakage of stool and straining
Magnesium Citrate: Indications
- short term relief of constipation
- prevent straining when clinically undesirable
- evacuate the bowel for diagnostic procedures
- remove ingested poisons from lower GI tract
- adjunct in anthelmintic therapy when it is desirable to flush helminths from GI tract
Magnesium Citrate: Actions
- Increase motility of the GI tract by increasing the fluid in the intestinal contents = enlarges bulk, stimulates local stretch receptors, and activates local activity
Magnesium Citrate: Adverse Effects
- diarrhea
- abdominal cramps
- bloating
- perianal irritation
- dizziness
Castor Oil: Indications
- evacuate the bowel for diagnostic procedures
- remove ingested poison from the lower GI tract
- adjunct in anthelmintic therapy when it is desirable to flush helminths from GI tract
Castor Oil: Actions
- directly stimulates the nerve plexus in the intestinal wall
- causing increased movement and the stimulation of local reflexes
Castor Oil: Adverse Effects
- Diarrhea
- abdominal cramps
- perianal irritation
- dizziness
- cathartic dependence (laxative dependent)
what do gastrointestinal stimulants do?
- increase GI activity and rapid movement of food through the GI tract
- block dopamine receptors and makes the GI cells more sensitive to Acetylcholine
what is the prototype of GI stimulant
Metoclopramide (Reglan)
Metoclopramide: Indications
- relief of acute and chronic diabetic gastroparesis
- short term treatment of gastroesophageal reflux disorder in adults who cannot tolerate standard therapy
- prevention of postop or chemo induced N/V
- facilitation of small bowel intubation
- stimulation of gastric emptying
- promotion of intestinal transit of barium
Metoclopramide: Action
- stimulates movement of the upper GI tract w/out stimulating gastric, pancreatic, or biliary secretions
- appears to sensitize tissue to the effects of acetylcholine
Metoclopramide: Adverse Effects
- n/v
- diarrhea
- intestinal spasms
- cramping
- decreased BP and HR
- weakness
- fatigue
- restlessness
- drowsiness
- extrapyramidal effects
- parkinson-like reactions
Metoclopramide: drug-drug interaction
- Digoxin: decreased absorption when combined with metoclopramide
- cyclosporine: decreased immunosuppresive effects and increased toxicity when combined with metoclopramide
- alcohol: increased sedation
what do antidiarrheals do?
block stimulation of the GI tract for symptomatic relief from diarrhea
what is the prototype of antidiarrheal
Loperamide
Loperamide: Indication
- control and symptomatic relief of acute, nonspecific diarrhea and chronic diarrhea associated w/ irritable bowel syndrome
- reduction of vol. of discharge from ileostomies
Loperamide: Action
inhibits intestinal peristalsis through direct effects on the longitudinal and circular muscles of the intestinal wall, slowing motility and movement of water and electrolytes
Loperamide: Adverse Effects
- abdominal pain
- distention
- discomfort
- dry mouth
- nausea
- constipation
- dizziness
- tiredness
- drowsiness
