Gastrointestinal Tract Flashcards
(14 cards)
Metoclopramide
Promotility (Prokinetic) Agent
Peripherally and centrally acting D2-antagonist.
It increases LES pressure and accelerates gastric emptying.
Causes extrapyramidal side effects and hyperprolactinemia.
FDA Warning—may cause Tardive Dyskinesia.
Domperidone
Promotility (Prokinetic) Agent
Peripheral D2-antagonist. Improves upper GI motility—increase gastric emptying.
Promote lactation by blocking the D2-receptors.
Can cause fatal QT-interval prolongation; mostly when used with CYP3A4 inhibitors.
Cisapride and Mosapride
Prokinetic (Promotility) Agents
Serotonin 5HT-4 receptor agonists. (This receptor’s stimulation increases ACh release in the enteric nervous system)
Life threatening QT-interval prolongation if used with CYP3A4 inhibitors.
Itopride
Promotility (Prokinetic) Agent
Combined D2-antagonist and AChE-Inhibitor.
No effect on QT-interval; unlike Mosapride and Cisapride.
May cause leukopenia.
Anti-secretory Antidiarrheal Agents
Racecadotril: an anti-secretory agent acts peripherally as Enkephalinase inhibitor, increasing Enkephalins levels; leading to inhibition of fluid/electrolyte depltion.
Racecadotril has no effect on motility, used as an adjuvant to ORS.
Bismuth Subsalicylate is an anti-secretory, anti-inflammatory and antibacterial.
Adsorbent Agents
Methylcellulose and Kaolin-Pectin—coating and protecting intestinal mucosa or adsorbing intestinal toxins.
Stimulant (Irritant) Laxatives
Senna, Bisacodyl, Picosulfate and Castor Oil—Purgatives.
Short-term relief of acute or intermittent constipation.
Onset: 6-10 hours.
Bulk-forming Laxatives
Psyllium (Ispaghula), Wheat Bran, Methylcellulose, Polycarbophil—Fibers. (Prebiotics)
For intermittent/chronic constipation. However, least effective; require adequate water intake.
May cause gas and bloating.
Safe in renal and hepatic disease and can be used in pregnancy and geriatrics.
Onset: 12-72 hours.
Osmotic Laxatives
Glycerin, Lactulose and Macrogol (PEG).
Lactulose lowers the colonic pH and is also used in hepatic encephalopathy. Safe. Onset is 1-2 days.
Saline Osmotic Laxatives (Saline Cathartics)
Sodium Phosphate, Magnesium Hydroxide, Magnesium Citrate and Magnesium Sulfate
Stool Softener (Emollient/Surfactant) Laxatives
Emulsify the stool.
Onset orally is 1-3 days and 5-20 minutes rectally.
Used in prophylaxis rather than acute treatment.
Needs adequate water for effectiveness.
OK in pregnancy.
Lubricant Laxatives
Mineral Oil or Paraffin Oil.
Pinaverium
An antispasmodic for IBS—acts as a calcium channel blocker.
Trimebutine
An antispasmodic for IBS—anti-muscarinic and weak u-opioid agonist effects.
