procainamide derivative- metoclopramide *reglan blocks receptors in the crtz. prokinetic drug:...
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Procainamide Derivative- Metoclopramide *Reglan
• Blocks receptors in the CRTZ.
• Prokinetic drug: increases gastric contractions and speeds emptying, strengthens cardiac sphincter tone.
• DO NOT GIVE WITH GI OBSTRUCTION
• More effective in dogs than cats.
Antihistamines- Diphenhydramine *Benadryl, Dimenhydrinate *Dramamine
• Used for vomiting caused by motion sickness or inner ear abnormalities.
• Decrease impulses sent from the vestibular apparatus by blocking H1 receptors at the CRTZ.
• More effective in dogs than cats.
• May cause sedation.
• Although injectables are available, oral dose can be given prophylactically.
Serotonin Receptor Antagonists- Ondansetron *Zofran, Dolasetron
*Anzemet
• Also called 5-HT3 receptor antagonists, these drugs block serotonin (a neurotransmitter) receptors on the vagus nerve and in the CRTZ.
• Used when emesis is caused by cytotoxic chemotherapy drugs
• Pricey, but may be worth it for short-term treatment.
NK-1 Receptor Antagonist- Maropitant citrate *Cerenia
• Inhibit the binding of Substance P (a neuropeptide) to neurokinin receptors in the Emetic center.
• Injectable form is approved for use in both dogs and cats. Oral form is for dogs.
• Injection may be painful.
• Can be given prophylactically to prevent motion sickness (without causing drowsiness), but also used to treat vomiting from other causes.
ANTIDIARRHEALS
Atropine, Aminopentamide,
Propantheline Loperamide,
DiphenoxylateBismuth subsalicylate
Sulfasalazine
• Diarrhea is the abnormal frequency and liquidity of fecal material due to failure of the intestinal tract to adequately absorb fluids from the intestinal contents.
– It is NOT a disease
– It IS a sign of disease
– It is a normal protective mechanism to remove substances from the GI tract.
• Antidiarrheals change intestinal motility or reduce secretions.
Motility Modifiers
• Increase segmental contractions and/or decrease peristaltic contractions to slow the movement of feces.
Anticholinergics- Atropine, Aminopentamide *Centrine, Propantheline
*Pro-Banthine
• Work against the effects of the neurotransmitter Acetylcholine. Also called parasympatholytics.
• Use with caution in animals who are already in Sympathetic mode (tachycardia, ileus)
• Most effective at reducing spastic contractions of the colon and diarrhea associated with tenesmus.
Opiod family- Loperamide *Immodium, Diphenoxylate
*Lomotil• Increase segmental contractions, decrease intestinal
secretions, enhance intestinal absorption.
• Use with caution in cats and horses as they can cause CNS stimulation/excitement.
• Can cause constipation, ileus, sedation. May also mask GI pain.
• Atropine is often added to discourage abuse (will cause dry mouth).
• Lomotil is a Class V controlled substance, Immodium is OTC
Antisecretory agents
• Stimulation of the cells that line the GI tract can result in secretion of ions that pull water with them into the gut lumen.
• When inflammation damages the tight junctions between GI cells, sugars, proteins, and red blood cells can also be lost in the lumen.
• These animals are at risk for dehydration.
• The opioids listed on the previous slide are also in this category.
Bismuth subsalicylate *Pepto-Bismol, *Kaopectate
• Breaks down in the gut to bismuth carbonate and salicylate. Bismuth coats the mucosa, decreases secretions, and has an anti-bacterial effect, while salicylate (aspirin-like compound) decreases inflammation and secretions.
• Cats as they have limited ability to metabolize/excrete salicylates.
• Bismuth can cause stools to become black and tarry, resembling melena.
• Shows up opaque on radiographs.
• Animals dislike the taste. Refrigeration may help or use tablet form.
Sulfasalazine *Azulfidine
• Sulfonamide antimicrobial that is chemically similar to a salicylate, producing an anti-inflammatory effect and decreasing GI secretions.
• Use with caution in cats.
• Little effect as an antibacterial.
ADSORBENTS/PROTECTANTS
-Many toxins/irritants cause hypersecretion and diarrhea by coming into direct contact with intestinal mucosal cells. An ADSORBENT will prevent this by adhering to the substance while a PROTECTANT will coat the gut wall like a blanket.
BismuthBarium
KaolinPectin
Bismuth• Active ingredient in Pepto-Bismol and Kaopectate
• Protectant that also reduces GI secretions.
Barium• Provides radiographic contrast.
• Protectant that may also reduce chronic diarrhea.
Activated Charcoal
• Adsorbent that has little effect on diarrhea.
• Decreases a toxin’s ability to be absorbed by the body.
• Charcoal and toxin are excreted in the feces.
• Messy!
Kaolin and pectin *Kaopectolin• Kaolin is a clay and pectin is a polysaccharide found in plant cell
walls.
• Combination acts as an adsorbent for bacteria and enterotoxins to bind to.
• Do not give simultaneously with other oral medications.
• Improves vomiting and diarrhea.