1. LAXATIVES AND CATHARTICS
Lactulose, Milk of Magnesia
Increase fluid content of feces, making them softer and easier to pass.
-Used for animals with constipation, trichobezoars, colon evacuation, pelvic fractures, and surgeries of the rear-end
-Laxatives are used when the goal is to soften the stool, Cathartics are used when evacuation of the bowel is the goal.
Metamucil, Bran, Docusate sodium
Mineral oil, Petrolatum, Glycerin

2. Emollient laxatives- mineral oil, cod liver oil, petrolatum (Laxatone)
Oils that soften the fecal mass, making it easier to move through the body.
Mineral oil is often used in horses with impaction and/or colic. Must ensure that nasogastric tube is not in the lungs!
Petrolatum is often used in cats with hairballs.

3. Emollient laxatives- glycerin, docusate sodium succinate (________)
Glycerin is in suppository form; stools are softened to pass through narrow pelvic canal
DSS is often in enema form; allows water to penetrate dry, hard stool.

4. Bulking laxatives- Metamucil, bran
Psyllium preparations that are indigestible; cause stool to swell with water to increase the size of intestinal contents and stimulate peristalsis.
Flatulence increases

5. Cathartics- Milk of Magnesia, lactulose
Milk of magnesia is an osmotic cathartic that contain magnesium or phosphate salts that are poorly absorbed. Pulls water into the bowel lumen via osmosis.
CCK is released which increases peristalsis.
Can cause electrolyte imbalances if treatment is prolonged or large doses are given.
Lactulose is an osmotic sugar cathartic that treats constipation and reduces ammonia absorption, which is helpful in patients with hepatic encephalopathy.

6. ANTIULCER MEDICATIONS
Causes of ulcers: gastric hyperacidity, bile reflux from duodenum to stomach, accumulation of toxins in the blood (renal failure), stress, inhibition of Prostaglandin Type E, drugs (steroids, NSAIDS)
Signs of ulcers: anorexia, hematemesis, pain, melena
NOTE: Many of these products effect the pH of the stomach. Be sure to read the package insert as they will instruct not to give other oral meds for 2 hours after administration.
ANTIULCER MEDICATIONS
Omeprazole, Lansoprazole
Cimetidine , Ranitidine, Famotidine, Sucralfate
TUMS, Rolaids, Maalox, Mylanta, Amphojel
Misoprostol

7. Nonsystemic antacids- TUMS, Rolaids, Maalox, Mylanta, Amphojel
Fast-acting, relatively nonabsorbable salts of aluminum, calcium, or magnesium taken PO to neutralize acid molecules by converting HCl to weaker acids.
Can affect other drugs by adsorbing to them, increasing stomach pH, and increasing urinary pH
Calcium and aluminum products can cause constipation, magnesium products can cause diarrhea. Many products contain both to counteract these effects.

8. Systemic Antacids
H2 Blockers- cimetidine (_________), ranitidine (__________), and famotidine (__________)
H2 receptors are one of three types of receptors on parietal cells. When receptor is stimulated by histamine, more hydrochloric acid is released from parietal cells.
H2 blockers block the receptors and reduce the production of HCl.

9. H2 Blockers cont’d
Cimetidine is the least potent- must be given up to 4 times a day to see results. Ranitidine is given less frequently- twice daily. Famotidine is only given once daily.
Cimetidine inhibits some of the liver enzymes needed to metabolize other drugs. If given with other meds (especially cardiac drugs), cimetidine may cause their concentrations in the blood to rise to toxic levels.
All come in oral (OTC and Rx) and injectable forms 

10. Proton Pump Inhibitors- omeprazole (__________, __________, ___________), lansoprazole (__________)
Bind to the luminal surface of parietal cells and inhibits the pump that moves hydrogen ions out of the cell.
end in the suffix –azole
Omeprazole – used in horses older than 4 weeks. Primarily for ulcers due to too little hay intake, reoccurring ulcers, or a sensitive growing GI tract. Compounding must be done carefully.

11. Gastromucosal protectant- sucralfate (_________)
Disaccharide that forms a paste in the stomach and binds to the surface of ulcers to promote healing (gastric Band-aid).
Increases mucus production and blood flow to ulcer site.
Avoid giving with drugs that alkalinize the stomach because it works better in the normal pH of the stomach (2-3)
Nonabsorbable
Only side effect is constipation

12. Prostaglandin Analogue- misoprostol (_________)
Increases mucus production, decreases acid production.
Used to treat ulcers due to large doses of NSAIDS.
$$$
Can cause colic in horses
May cause abortion in both patient and administrator

13. MISCELLANEOUS GI DRUGS

14. RUMINATORIC- neostigmine
Prokinetics that stimulate a flaccid rumen.
Stimulate the parasympathetic nervous system to increase GI motility.
Will cause other signs of PNS stimulation

15. ANTIBLOAT- DSS, poloxalene
Reduce gas buildup or facilitate the removal of gas from the rumen
Rumen is at risk for frothy bloat
Gas distention in rumen from grazing certain plants (legumes usually) that mixes with fluid to cause a froth
This froth can kill them by blocking the ability to burp
These agents cause small gas bubbles to coalesce into a belchable gas pocket.

16. ANTIBIOTIC- metronidazole (_________)
Effective against anaerobic bacteria & Giardia
Often used to treat diarrhea as it reduces inflammation in the GI tract and returns stool to its normal consistency.
Neurological signs may be seen with moderate to
high doses
Carcinogenic in food animals

17. ENZYMATIC SUPPLEMENTATION- Viokase, Pancrezyme
Treatment for Pancreatic Enzyme Insufficiency which causes maldigestion and malabsorption
Pancreas is not making its digestive enzymes
Amylase, lipase, protease (enzymes used to digest fat, starch, and protein)
The enzymes can be provided to the patient in the diet