GERD And Lower GI Flashcards
Gastro-esophageal reflux disease (GERD) mechanism
- transient lower esophageal relaxation
- sphincter at the base of the esophagus relaxes
- this allows acid to reflux back up into the esophagus
D2 antagonist
Metoclopramide
Domperidone
Metoclopromide mechanism
Effects on the upper GIT:
- increase lower esophageal sphincter tone
- increases contractions, gastric emptying (moves food out of the stomach faster)
- inhibits chemoreceptor trigger zone (anti-nauseant)
Metoclopromide side effects
- Pseudoparkinsonism
- Hyperprolactinemia
Domperidone mechanisms and AE’s
- Same effects as Metoclopromide
- Works outside the CNS, therefore no movement disorders
- Hyperprolactinemia
Motilin agonist
Erythromycin
Erythromycin mechanism
- stimulates peristalsis by stimulating the motilin receptor
- can therefore use this side effect as a beneficial effect to increase GI motility
Serotonin agonist
Prucalopride
Prucalopride mechanism
Stimulates peristalsis via 5HT-4
-
Prucalopride side effects
Nausea
Diarrhea
Abdominal Cramps
Disorders of the lower GI tract (4)
Diarrhea
Constipation
Inflammation
Irritation
Treating Diarrhea
Opioid agonists
Act on mu receptors, decrease peristalsis
- Loperamide
Why does loperamide have minimal CNS Mu effects?
Loperamide has limited ability to cross the blood brain barrier
Loperamide side effects
Constipation High (toxic) doses: Arrhythmia
Laxatives categories (6)
Bulk Osmotic Stimulant Softeners Opioid antagonists Other
Bulk Laxative example
Fibre
Fibre (Psyllium) mechanism
Pulls water into the stool, increase in bulk leads to increase in peristalsis
Osmotic examples
Polyethylene glycol
Magnesium hydroxide
Osmotic’s mechanism
Pulls water into the colon
Stimulant examples
Bisacodyl
Sennosides
Stimulant’s mechanism
Directly stimulate the colon, increasing peristalsis
Softener example
Docusate
Softeners mechanism
Emollient effect
Enhances secretion of intestinal fluids
However, all mush, no push
Softeners side effects
Mild GI cramping
Opioid antagonists example
Methylnaltrexone
Methylnaltrexone mechanism
- like naltrexone but polar, so does not cross into the CNS
- blocks peripheral opioid receptors, no impact on pain
Opioid Antagonists side effects
Diarrhea
Nausea
Cramps
cGMP agonist
Linaclotide
Linaclotide mechanism
Intestinal secretagogue
- increases intestinal secretions
- reduces transmission of pain signals
cGMP agonist side effects
Diarrhea