cearticle #2 ce test - VetLearn.com

CE 

452 V 

Vol. 24, No. 6 June 2002 

Article #2 (1.5 contact hours) 

Refereed Peer Review 

KEY FACTS 

■ Xylazine is considered the drug of 

choice for stimulating emesis in 

cats, but it does not have 

consistent results in dogs. 

■ Serotonin antagonists are 

considered the most potent 

inhibitors of vomiting. 

■ H 2-receptor antagonists 

ranitidine and nizatidine are also 

acetylcholinesterase inhibitors 

with prokinetic effects at the 

clinically recommended doses. 

Comments? Questions? 

Email: compendium@medimedia.com 

Web: VetLearn.com • Fax: 800-556-3288 

Drug Therapies Used 

in Gastrointestinal 

Disease 

Oklahoma State University 

Susan M. Eddlestone, DVM, DACVIM 

ABSTRACT: Initial treatment of most gastrointestinal disorders in dogs and cats has traditionally 

been supportive and nonspecific. With the improved ability to diagnose many gastrointestinal 

disorders less invasively using endoscopy, serology, and fecal and rectal mucosal 

cytology, specific treatments can be applied earlier with marked improvement in clinical 

results. This article discusses the indications and uses of the most common treatments in 

small animal gastroenterology as well as newer therapies that are emerging and being 

received with favorable results. 

The treatment of gastrointestinal (GI) clinical signs and definitive disease 

in dogs and cats is often chosen based on the practitioner’s knowledge 

and experience with treatments known to be effective. This article 

reviews the traditional treatment modalities and provides an introduction to 

newer therapies that are being used successfully to treat many GI disorders in 

dogs and cats. 

VOMITING REFLEX 

The emetic center, which is located in the medulla of the brain, coordinates all 

impulses that cause vomiting. The emetic center is protected by the blood–brain 

barrier; therefore, input to this region occurs from the cerebral cortex (e.g., psychogenic 

vomiting, visual and olfactory stimuli), the limbic system (e.g., head 

injuries, increased intracranial pressure), the chemoreceptor trigger zone (CTZ), 

and peripheral impulses. Acetylcholine is the primary afferent neurotransmitter, 

mediating emesis from the higher centers with histamine acting as a secondary 

transmitter via H 1 receptors. Blood-borne chemicals stimulate the CTZ, which is 

located in the area postrema in the lateral walls of the third ventricle. Because this 

area does not have a complete blood–brain barrier, it is more accessible to substances, 

drugs, or toxins present in the circulating blood than is the emetic center. 

Stimulation of the CTZ is initiated by dopaminergic receptors that respond to 

such agonists as dopamine, apomorphine hydrochloride, and serotonin (5-HT 3). 

Peripheral impulses originate in the pharynx and fauces and travel to the emetic 

center via cranial nerve IX. Other peripheral afferent impulses originate from stimulation 

in various organs and tissues via the sympathetic or vagal afferents (i.e., 

heart, stomach, duodenum, small intestine, liver, gallbladder, peritoneum, kidneys, 

ureter, urinary bladder, and uterus). 1

Compendium June 2002 Drug Therapy/GI Disease 453 

Table 1. Emetic Drugs 

Drug Dose Comment 

3% Hydrogen peroxide Dogs and cats: 5–10 ml PO, one to two 

doses as needed 

Fatal aspiration of foam is possible in cats 

Ipecac syrup Dogs: 1–2.5 ml/kg PO; cats: 1–3.3 Not to exceed 15 ml/dog; dogs and 

ml/kg PO (may cause toxicity and death) cats: dose may be repeated once but 

product must be removed via gastric 

lavage if vomiting does not occur 

Apomorphine hydrochloride Dogs: 0.04 mg/kg IV, 0.08–0.1 mg/kg 

IM or SC, or 0.25 mg (conjunctival sac) 

Not recommended for use in cats 

Xylazine Cats: 0.44 mg/kg IM Not effective in dogs; emesis in cats 

should occur within 15 min; 

sedation lasts 1–2 hr 

EMETICS 

Emetics are used to induce vomiting in dogs and cats 

for early treatment of ingestion of noncorrosive toxins. 

Within the first 30 minutes to 1 hour after toxic ingestion, 

emetics can help eliminate the toxin from the 

stomach before they are absorbed in the small intestine. 

Emesis should never be induced in patients that are 

unconscious, experiencing a seizure, or having respiratory 

difficulty. Reflux emesis can be induced by instilling 

warm water (5 to 10 ml/kg) into the stomach via a 

stomach tube. This will dilute the toxin and initiate the 

vomiting reflex by stimulating peripheral receptors in 

the stomach that respond to distention. 

Gastric mucosa irritants can also induce the vomiting 

reflex peripherally. Orally administered hypertonic 

saline solution or table salt, 3% hydrogen peroxide 

solution, or ipecac syrup or powder (i.e., emetine) can 

be effective and administered at home prior to an emergency 

visit (Table 1). Ipecac in cats can be toxic, particularly 

with the administration of multiple doses that 

can be absorbed systemically. Hydrogen peroxide can 

foam and cause fatal aspiration in cats; therefore, it 

should be used with caution in this species. 1 

Centrally acting drugs are more potent stimulants of 

the vomiting reflex. Apomorphine hydrochloride, an opioid 

and synthetic derivative of morphine, stimulates the 

CTZ by acting on dopamine receptors. 1 It is available as a 

powder inside a capsule and can be mixed in sterile water 

and given subcutaneously. The tablet form, which is more 

expensive, can be used in the conjunctival sac for quick 

absorption. Oral administration usually requires a much 

higher dose because of decreased oral bioavailability. 1 

Likewise, giving subsequent doses does not improve the 

vomiting effect but may actually suppress the emetic center. 

Although considered only a mild CNS depressant, 

apomorphine hydrochloride should not be used in animals 

with depressed CNS conditions. Apomorphine 

hydrochloride is not recommended for use in cats because 

they need a higher dose to induce vomiting, and this can 

cause excitement and hyperactivity of the CNS. 1 

Xylazine, an α 2-agonist, is the drug of choice to stimulate 

emesis in cats. 1 Although it is used more commonly 

for its sedation/analgesic properties, it can be 

used at a lower dose to induce vomiting in cats. In dogs, 

xylazine is not as consistent at inducing emesis. There 

are no reports on the use of medetomidine, a drug with 

similar actions, to induce emesis in either species. 

ANTIEMETICS 

Vomiting occurs in dogs and cats as a result of many 

GI and non-GI disorders. Suppression of vomiting is 

indicated when the underlying cause is known and 

serves to prevent further metabolic alterations caused 

by the loss of fluid, gastric acids, and electrolytes. 

Although treatment of the underlying cause is always 

the primary objective, the use of antiemetics for the 

interim to prevent further debilitation is beneficial. 

Suppressing vomition is contraindicated in patients 

with pyloric or intestinal obstruction. 

Dopamine Antagonists 

Metoclopramide, a dopamine antagonist, blocks 

dopamine receptors at the CTZ 2 (Table 2). It is suspected 

that at higher doses, antagonism is at the 5-HT 3 receptors. 

This agent is reported to be 20 times more potent than 

phenothiazines, although this difference in efficacy has not 

been documented in dogs and cats. 3 Metoclopramide also 

has prokinetic effects, which may help minimize vomiting 

by increasing upper GI motility, increasing lower 

esophageal sphincter tone, decreasing pyloric sphincter 

tone, and promoting antegrade contraction of the gastric 

antrum. A side effect is CNS stimulation that presents as 

irritability or nervousness, particularly in cats. The antidote 

for this side effect is diphenhydramine hydrochloride

454 Small Animal/Exotics Compendium June 2002 

Table 2. Antiemetic Drugs 


Metoclopramide Dogs and cats: 0.1–0.5 mg/kg PO or Use lower doses with renal failure; 

SC q8h, 0.02 mg/kg IV q1h, or 1–2 common side effects are anxiety and 

mg/kg/day IV by CRI restlessness in dogs and cats 

Domperidone Dogs and cats: 0.1–0.5 mg/kg IM or 

IV q12h or 2–5 mg/kg PO q12h 

Not available in the United States 

Ondansetron Dogs and cats: 0.1–0.2 mg/kg SC q8h, No side effects are known; further 

0.1–1.0 mg/kg q12–24h PO, 0.5 mg/kg 

IV load, or 0.5 mg/kg IV infusion q1h 

investigation is needed in dogs and cats 

Dolasetron Dogs and cats: to prevent nausea or Can be combined with metoclopramide 

vomiting—0.6 mg/kg/day IV or PO; for optimal prevention of chemotherapyvomiting—1 

mg/kg/day IV or PO induced nausea and vomiting in dogs 

and cats 

Chlorpromazine Dogs: 0.2–0.4 mg/kg IM or SC q6–8h, 

3.3 mg/kg PO q6–8h; cats: 0.5 mg/kg 

IM or SC q6–8h, 2.0–4.0 mg/kg/day PO 

May cause sedation 

Prochlorperazine Dogs: 0.25–0.5 mg/kg IM q8–12h 

or 1 mg/kg PO q12h; cats: 0.13 mg/kg 

IM q12h or 0.5 mg/kg PO q12h with food 

May cause sedation in dogs and cats 

Trifluoperazine Dogs and cats: 0.03 mg/kg IM q12h May cause sedation in dogs and cats 

Cyclizine hydrochloride Dogs and cats: 4 mg/kg IM q8h For vestibular disease–induced emesis 

Meclizine hydrochloride Dogs 10 kg: 2–6 mg/kg/day PO; 

cats: 4 mg/kg/day PO 

For vestibular disease–induced emesis 

Diphenhydramine hydrochloride Dogs and cats: 2–5 mg/kg PO q6–8h, For vestibular disease–induced emesis 

2 mg/kg IM or IV (slowly) q12h 

CRI = constant-rate infusion. 

(1 mg/kg IV) in dogs and cats. 4 Contraindications are GI 

hemorrhage and obstruction. Other dopamine antagonists 

that have been available but less commonly used are domperidone 

and the butyrophenone derivatives haloperidol 

and droperidol. Domperidone, which is similar to metoclopramide 

in activity, is currently not available in the 

United States for use in dogs and cats. The butyrophenones 

cause potent tranquilizer side effects and seizures in 

preepileptic patients. 

Serotonin Antagonists 

Serotonin antagonists, also known as 5-HT 3 antagonists, 

are a relatively new class of antiemetic drug that 

blocks stimulation at the CTZ and in the intestine to 

prevent vomiting. 5 The neurotransmitter serotonin acts 

by increasing the secretion of acetylcholine at distal 

ganglia, thereby stimulating the CTZ to induce vomiting. 

Serotonin antagonists block this mechanism and 

are considered the most potent inhibitors of vomiting. 

They are particularly useful for preventing vomiting 

induced by chemotherapy, parvovirus, and causes that 

are resistant to other therapies. 5-HT 3 antagonists that 

are available include ondansetron, tropisetron, 

granisetron, azesetron, and dolasetron. Ondansetron 

and dolasetron have been reported to be very effective 

in both dogs and cats 6 ; however, the high cost of these 

drugs limits their use to chemotherapy patients or 

patients unresponsive to other medications. Side effects 

have not been reported in dogs and cats; however, indepth 

study of these drugs in companion animals have 

not been published. 

Phenothiazines 

Phenothiazines control vomiting by inhibiting the 

CTZ as a result of their antidopaminergic and antihistaminergic 

effects. 2 Phenothiazine derivatives used as 

antiemetics in small animals include chlorpromazine, 

prochlorperazine, triflupromazine, perphenazine, trifluoperazine, 

and mepazine. Side effects associated with phenothiazines 

are sedation, hypotension caused by peripheral 

α blockade, and seizures in preepileptic patients. 

Glucocorticoids 

Glucocorticoids are used in human medicine to con-


Table 3. Antisecretory Drugs 


Cimetidine Dogs and cats: 5–10 mg/kg PO q6–8h Give IV dose slowly over 30–40 min 

or 10 mg/kg IV q6h in dogs and cats; cytochrome P450 

microsomal enzyme inhibitor 

Ranitidine Dogs and cats: 0.5–2 mg/kg PO, 

IV, IM, or SC q8–12h 

No serious side effects reported 

Famotidine Dogs and cats: 0.5–1.0 mg/kg PO 

or IV q12–24h 

No serious side effects reported 

Nizatidine Dogs: 5 mg/kg/day PO No serious side effects reported 

Omeprazole Dogs: 0.5–1.0 mg/kg/day PO Achlorhydria, diarrhea, and transient 

fluctuations in liver enzymes reported 

trol vomiting, although the exact mechanism of action 

is not understood. These agents may have a synergistic 

effect when used with other antiemetics, such as metoclopramide, 

particularly when used in chemotherapy 

patients. Because of the side effects of gastric, duodenal, 

and colonic ulceration, the use of glucocorticoids 

for vomiting is not recommended. 

Barbiturates and Benzodiazepines 

Barbiturates (e.g., phenobarbital) and benzodiazepines 

(e.g., diazepam) are sedatives that are used to control 

psychogenic and behavioral vomiting by acting on the 

higher centers of the brain. This type of vomiting, however, 

is not well documented in veterinary medicine. 

Anticholinergics 

Anticholinergics (e.g., atropine) are centrally acting 

antiemetics that block cholinergic transmission as well as 

muscarinic receptors in the emetic center. Many anticholinergics 

(e.g., glycopyrrolate, propantheline, meth-


Table 4. Cytoprotective Drugs and Antacids 


Aluminum magnesium hydroxide Dogs and cats: 2–10 ml PO q2–4h Preferred combination to avoid 

side effects 

Aluminum carbonate gel Dogs and cats: 10–30 mg/kg PO Can cause diarrhea, nausea, GI upset, 

q8h with meals constipation, and hypophosphatemia 

Aluminum hydroxide Dogs and cats: 30–90 mg/kg PO Binds bile salts and phosphorus; 

q8–24h with meals inactivates pepsin; can cause 

constipation 

Magnesium hydroxide Dogs: 5–30 ml PO q8–24h; Can cause diarrhea; avoid 

cats: 5–10 ml PO q8–24h magnesium-based products in 

patients with renal failure 

Calcium carbonate Dogs: 50–75 mg/kg divided daily Can cause metabolic alkalosis, 

q8–12h PO hypercalcemia, calciuria, 

hypophosphatemia, and constipation 

Misoprostol Dogs and cats: 2–5 µg/kg PO q6–8h Prevents NSAID-induced gastric ulcers 

Sucralfate Dogs 15 kg: 1-g tablet q6–8h; before or after other drugs (may bind 

cats: 1 /4 - to 1 /2-g tablet q8–12h with other medications if administered 

together) 

scopolamine [not recommended for use in cats], and isopropamide) 

do not cross the blood–brain barrier; therefore, 

they act peripherally. Peripheral actions that prevent 

vomiting are due to inhibition of afferent vagal stimulation, 

relaxation of smooth muscle, and inhibition of GI 

secretions. Unfortunately, the limiting effect is that they 

promote delayed gastric emptying and decreased intestinal 

motility, causing GI overdistention, which may in 

itself cause vomiting. They also inhibit the actions of 

such drugs as metoclopramide, cisapride, and opioids 

that are dependent on cholinergic activity in ganglia or 

smooth muscle. Because this inhibition limits their usefulness, 

anticholinergics are not usually recommended. 1 

Antihistamines 

Antihistamines are used to control vomiting caused by 

motion sickness or inner-ear disease, which is mediated 

by the vestibular apparatus. Cyclizine hydrochloride, 

meclizine hydrochloride, or diphenhydramine hydrochloride 

may control vomiting for several hours. 2 Side effects 

of antihistamines include drowsiness and dry mouth. 

GASTRIC ANTISECRETORY DRUGS 

Gastric antisecretory drugs are most commonly used 

to treat gastric inflammation and ulceration (Table 3). 

Gastric ulceration caused by drugs, toxins, trauma, 

immune-mediated disease, or neoplasia may be treated 

by reducing the acidity of gastric secretions. Esophagitis 

caused by foreign bodies, ingestion of caustic substances, 

gastric reflux during anesthesia, and chronic 

vomiting are also treated by reducing gastric acidity and 

reflux of gastric fluid. 

H2-Receptor Antagonists 

H2-receptor antagonists (H2 blockers), which are relatively 

inexpensive, are the most widely available drugs 

that reduce hydrogen ion content of gastric secretions 

and the amount of pepsin induced by other secretory 

enzymes. In addition, these drugs, particularly the 

newer ones (e.g., ranitidine, nizatidine), may also promote 

gastric prokinetic activity due to anticholinesterase 

properties. The potency and duration of action 

of H2 blockers are rated as follows: 

Famotidine > ranitidine > cimetidine2 Gastric motility potency studied in guinea pig muscle is 

rated as follows: 

Nizatidine = ranitidine > cimetidine > famotidine7 Cimetidine inhibits the cytochrome P450 microsomal 

enzyme system in the liver and thus impairs the metabolism 

of other drugs and should be avoided in animals with 

liver disease or when being used with other medications 

that are metabolized by the liver. Rebound hypersecretion 

of gastric acid is believed to be the cause for relapse of gastroduodenal 

ulcers in humans when H 2 blockers are discontinued. 

8 Most H 2 blockers are available over the 

counter, making dispensing and refilling them easy. 

Proton Pump Inhibitors 

Proton pump inhibitors are substituted benzimida-


Table 5. Protectants and Adsorbents 


Kaolin–pectin Dogs and cats: 1–2 ml PO q2–6h Used for nonspecific treatment 

of diarrhea 

Bismuth subsalicylate Dogs: 0.25–2 ml/kg PO q4–6h; cats: Cats should not receive frequent or 

0.25 ml/kg PO q4–6h high doses because of possible 

salicylate toxicity 

Activated charcoal Dogs and cats: 1–4 g/kg PO slurry, as Best if used within the first hour of 

needed (1 g/5 ml water); 6–10 ml/kg PO ingestion; slurry and suspension are 

suspension, as needed more absorptive than tablets 

Cholestyramine Dogs: 200–300 mg/kg PO q12h, Can cause hypochloremic acidosis, 

as needed steatorrhea, decreased fat-soluble 

vitamin absorption, and 

hypoproteinemia 

zoles and a new class of antisecretory drugs. They are 

potent antagonists of the H + /K + ATPase proton pump, 

which is the final step to secretion of hydrogen ions at 

the apex of the parietal (oxyntic) cell. Omeprazole is 

the most commonly used proton pump inhibitor in 

veterinary medicine and is reported to be 30 times 

more potent than the H 2 blocker cimetidine. 9 

Omeprazole is formulated as encapsulated entericcoated 

granules that are dissolved in the alkaline con- 

tents of the small intestine. The drug is absorbed into 

the systemic circulation and concentrated in the acidic 

environment of the parietal (oxyntic) cell, where it is 

converted to the inhibitor drug. There is a lag period 

of 3 to 5 days for the drug to accumulate in the parietal 

cell before maximum effects are seen. After this 

time, low serum concentrations will maintain the 

effect with once-daily dosing. Omeprazole is considered 

superior to H 2 blockers in the treatment of


Table 6. Motility-Modifier Drugs 


Metoclopramide Dogs and cats: 0.1–0.5 mg/kg PO or SC q8h LES, stomach, and small intestinal effects 

Domperidone Dogs and cats: 0.1–0.5 mg/kg IM or IV q12h LES, stomach, and small intestinal effects; 

or 2–5 mg/kg PO q12h not currently available in the United States 

Cisapride Dogs: 0.1–0.5 mg/kg PO q8–12h; cats: 2.5–5 LES, stomach, small intestinal, and colon 

mg PO q8–12h effects 

Diphenoxylate Dogs: 0.1–0.2 mg/kg or 2.5–10 mg PO q8h; Narcotic that contains atropine to 

hydrochloride cats: 0.05–0.1 mg/kg PO q12h or 0.6–1.2 mg prevent abuse; controlled substance; 

PO q8–12h used to treat diarrhea 

Loperamide hydrochloride Dogs: 0.08–0.20 mg/kg PO q8–12h; cats: Available over the counter due to lack of 

0.1–0.3 mg/kg PO q12–24h or 0.08–0.16 blood–brain barrier transmission; used 

mg/kg PO q12h to treat diarrhea 

Erythromycin Dogs and cats: 0.5–1.0 mg/kg PO q8h Give after meals; LES, stomach, and small 

intestinal effects 

Ranitidine Dogs and cats: 0.5–2 mg/kg PO, IV, IM, or 

SC q8–12h 

Stomach, small intestinal, and colon effects 

Nizatidine Dogs: 5 mg/kg/day PO Stomach, small intestinal, and colon effects 

Misoprostol Dogs and cats: 2–5 µg/kg PO q6–8h Colon effects; may be effective in 

refractory constipation 

LES = lower esophageal sphincter. 

esophageal and gastric inflammation and ulceration. 

Although the high cost of omeprazole may limit its 

use, the shorter recovery period and more successful 

outcome in severe cases may justify the expense. Side 

effects in animals are not reported when omeprazole is 

used less than 8 weeks. 10 

CYTOPROTECTIVE DRUGS AND ANTACIDS 

Cytoprotective drugs are commonly used in patients 

to decrease gastric acidity (Table 4). 

Antacids 

Antacids chemically neutralize hydrochloric acid in 

the gastric lumen, resulting in the generation of chlorides, 

water, and carbon dioxide. Some formulations 

(e.g., aluminum hydroxide) may also bind bile salts and 

inactivate pepsin. Some products induce local synthesis 

of the mucosal protectants, prostaglandins, and 

sulfhydryls. The duration of action of antacids is usually 

about 1 to 2 hours and is extended when food is 

present because of increased gastric pH. Administration 

of these drugs with food is required every 4 to 6 hours 

to prevent a gastric acid rebound effect, which occurs 

because the increased pH in the antral lumen stimulates 

increased serum gastrin levels. 

Aluminum, magnesium, and calcium salts can be 

used alone or in combination. In addition to antacid 

properties, aluminum salts absorb bile acids and 

pepsin and stimulate local prostaglandin production; 

however, they may cause constipation. Aluminum salts 

also bind phosphate, thereby reducing phosphate 

absorption. They are often used to manage patients 

with renal failure but can cause hypophosphatemia 

with prolonged use. Products containing magnesium 

are better at raising the gastric pH than are aluminum 

products. Unabsorbed magnesium salts, however, act 

as a laxative and can cause diarrhea. Therefore, a combination 

of aluminum and magnesium is the preferred 

antacid. Calcium carbonate is a potent and fast-acting 

antacid, but prolonged use may cause metabolic alkalosis, 

gastric-acid rebound, hypercalcemia, calciuria 

with metastatic calcification and urolithiasis, 

hypophosphatemia, and constipation. 11 

Misoprostol 

Other drugs that have antisecretory properties are 

prostaglandin analogues, but they are not as effective as 

H 2 blockers in decreasing intraluminal gastric pH. 

Misoprostol, a prostaglandin E 1 analogue, is an antisecretory 

drug as well as a cytoprotectant. Hydrochloric 

acid production is decreased by interaction with a basolateral 

membrane receptor, which decreases cyclic 

adenosine monophosphate, thus decreasing protein 

kinase activity and hydrogen ion concentration. 12 Misoprostol 

increases mucus and bicarbonate secretion and 

enhances the epithelialization of the mucosa and


mucosal blood flow. Its major effect is the ability to 

promote gastroduodenal ulcer healing. Preventive therapy 

or treatment of NSAID-induced gastroduodenal 

ulceration is the primary indication, but misoprostol 

may also be helpful in treating GI ulcers of other 

causes. 

Sucralfate 

Sucralfate is an orally administered disaccharide aluminum 

hydroxide product that binds to the submucosa 

of an ulcerated lesion in the stomach and duodenum 

and protects the submucosa from acid, bile salts, and 

pepsin activity. Binding also prevents exudation of protein 

and electrolytes and stimulates production of 

prostaglandins, sulfhydryl ions, and oxygen radical 

scavengers, which are natural gastric mucosal protectants. 

Potential binding and inhibition of other drugs 

may occur when given with sucralfate; therefore, sucralfate 

should be given on an empty stomach at least 2 

hours before or after other medications. 

PROTECTANTS AND ADSORBENTS 

Protectants are nonabsorbable compounds that line 

the GI mucosa and prevent irritation and erosion by 

potentially harmful substances (Table 5). Although 

commonly used for vomiting, protectants such as 

kaolin, pectin, bismuth salts, demulcents, and antacids 

generally do not work and often increase vomiting by 

causing stomach distention and irritation. Adsorbents 

physically bind chemicals to prevent their absorption 

and promote elimination in the feces. Commonly used 

products contain both absorbent and protective properties. 

Indications for these products in small animal medicine 

are limited, and studies showing efficacy are lacking. 

Kaolin–Pectin 

Kaolin–pectin is a demulcent and adsorbent that is 

used for the nonspecific treatment of diarrhea. 

Although improvement may be seen in the consistency 

of stools, kaolin–pectin has not been shown to reduce 

stool volume or shorten the course of the disease, and 

fluid and electrolyte loss remains unchanged. 13 

Bismuth Salts 

Bismuth salts are demulcents and lesser adsorbents. 

When given to rabbits experimentally, bismuth subcarbonate 

and subsalicylate have been shown to inhibit 

Escherichia coli and Vibrio cholerae enterotoxins when 

administered before or immediately after enterotoxins. 14 

They have benefit in preventing enterotoxin-induced


Table 7. Antimicrobials 

Drug Dose Indication Comment 

Ampicillin/ Dogs and cats: 10–20 mg/kg Gram-positive bacteria, Disrupts normal GI flora 

amoxicillin PO, IM, or IV q6–8h anaerobes 

Cephalexin Dogs and cats: 22 mg/kg PO Gram-positive bacteria, Disrupts normal GI flora; give 

q8–12h some gram-negative bacteria; 

mucosal injury, sepsis 

with food if vomiting occurs 

Metronidazole Dogs and cats: 10–20 mg/kg Bacterial overgrowth, Neurotoxicity at higher 

PO q8–12h anaerobes, IBD, Clostridium, doses; use one third of dose 

Giardia if liver disease is present 

Erythromycin Dogs and cats: 10 mg/kg PO q8h Campylobacteriosis Can cause GI upset 

Enrofloxacin Dogs: 2.5–5.0 mg/kg PO or IM Gram-positive bacteria, gram- Can cause cartilage 

q12h; cats: 2.5 mg/kg PO or IM negative bacteria, sepsis defects in puppies (if given 

q12h >5 mg/kg) and possible 

blindness in cats 

Sulfasalazine Dogs: 10–30 mg/kg PO q8h; IBD, colitis Can cause keratoconjunccats: 

20 mg/kg or 250 mg PO q8h tivitis sicca; use with caution 

(three times), then q24h in cats because of possible 


Tetracycline Dogs and cats: 20 mg/kg PO q8h Bacterial overgrowth, Can cause liver toxicity, 

hydrochloride rickettsial diarrhea, sepsis GI upset, discolored teeth 

(in puppies), drug fever 

(in cats) 

Gentamicin sulfate Dogs and cats: 2.2 mg/kg IM, Sepsis Can cause nephrotoxicity; 

IV, or SC q12h do not use in dehydrated 

patients or those with renal 

disease 

Tylosin Dogs and cats: 11–200 or Bacterial overgrowth, IBD Sprinkle on food; broad dose 

20–40 mg/kg PO q12h; range with wide safety 

5–10 mg/kg PO q8–12h; margin; each gram contains 

1 /4–1 tsp with food q8–12h 100 mg tylosin 

Trimethoprim Dogs and cats: 15 mg/kg PO Mucosal injury, gram-negative Immune disease (in liver, 

sulfonamide or SC q12h bacteria, Salmonella, coccidia bone marrow) is a possible 

reaction 

diarrhea but are not effective once clinical illness is apparent. 

Bismuth subsalicylate has been shown to have 

antiprostaglandin synthetase effects that enhance the ability 

to control diarrhea caused by the subsalicylate component. 

This compound should be used cautiously in cats 

because the subsalicylate is absorbed systemically and toxicity 

is associated with use of this drug in cats. 1 

Activated Charcoal 

Activated charcoal, which is a commonly used adsorbent 

to treat intoxications from ingestion of harmful drugs 

or substances, absorbs the toxin in the gut and decreases 

the amount of toxin entering the systemic circulation. If 

the drug or toxin is eliminated by the liver and reabsorbed 

in the intestine, activated charcoal can absorb the toxin 

and increase the rate of elimination from plasma and tis- 

sues. Timing of treatment is important for maximal efficacy, 

and delays of even 30 minutes can decrease absorption 

substantially. Activated charcoal is available in readymade 

liquid, powder, or tablet form; the liquid and 

powder forms are more absorptive than the tablets. 

Cholestyramine 

Cholestyramine is the chloride salt of a basic anion 

exchange resin and acts by forming ionic bonds with 

acidic side chains. 13 This drug is known for its bile 

acid–binding capacity and is used for bile acid–induced 

diarrhea following resection of the ileum. Cholestyramine 

can interfere with intestinal absorption of drugs 

(e.g., chlorothiazide, phenylbutazone, phenobarbital, 

anticoagulants, thyroxine, digitalis) and can be used to 

treat intoxication. Side effects include hypochloremic


acidosis, steatorrhea, decrease in fat-soluble vitamins, 

and hypoproteinemia (of an unknown mechanism). 

MOTILITY MODIFIERS 

Prokinetic therapy is indicated when there is either a 

primary or secondary effect of GI stasis (Table 6). 

Motility problems are often secondary to inflammatory, 

infiltrative, postobstructive, and postoperative conditions. 

Primary motility problems are most commonly 

seen as congenital or acquired megaesophagus and 

megacolon. Aging animals may also be predisposed to 

less than adequate motility secondary to common GI 

ailments caused by degeneration of their GI neuromuscular 

system. Differences in anatomy and physiology 

between species must be recognized. For example, the 

distal one third of the esophageal muscle in cats consists 

of smooth muscle compared with dogs, which 

have skeletal muscle throughout the esophagus. Therapies 

to improve motility in these varied situations 

depend on treatment of any underlying cause of GI stasis 

and then supplementation with prokinetic drugs 

until the underlying problem is resolved. Other more 

permanent conditions may require continual use of 

these drugs. Prokinetic drugs are categorized into 

classes based on their mechanism of action. 

Dopamine Antagonists 

Metoclopramide and domperidone, which are 

dopamine antagonists, inhibit peripheral and central 

dopamine receptors. 15 As previously discussed, these 

drugs are effective antiemetics because of the central 

inhibition of dopamine. The peripheral inhibition of 

dopamine is still not fully understood. These drugs 

may actually have other properties, such as serotonin 

inhibition and agonism (5-HT 3 and 5-HT 4 receptors), 

α 2- and β 2-adrenergic–receptor inhibition, and indirect 

cholinergic effects, which make them prokinetics. The 

major effects of these drugs are in the lower esophageal 

sphincter, stomach, and upper small intestine (i.e., 

duodenum, jejunum). 

Serotonin Agonists 

Cisapride, a serotonin agonist, acts on the 5-HT 4 and 

5-HT 2a (smooth muscle) receptors and is antagonistic 

to the 5-HT 1/5-HT 3 receptors. 16 Cisapride exerts its 

potent effects in the lower esophageal sphincter, stomach, 

small intestine, and colon. It is considered to be 

superior to metoclopramide in the treatment of gastroesophageal 

reflux, delayed gastric emptying, ileus, 

and constipation. However, cisapride is no longer produced 

because of its association with fatal arrhythmias


in humans. 17,18 Veterinarians must, therefore, consider using other classes of 

motility drugs that are available. 

Motilinlike Drugs 

Motilinlike drugs simulate the activity of the gut hormone motilin to induce 

motility in the GI tract. Erythromycin, a macrolide antibiotic, is also a motilinlike 

drug. When given at lower than microbially effective doses, erythromycin 

acts on the GI tract to stimulate migrating motility complexes and causes antegrade 

peristalsis similar to the actions induced by the endogenous hormone 

motilin. Direct action is believed to be via cholinergic and noncholinergic 

mechanisms in dogs. 19,20 These effects are seen in the lower esophageal sphincter, 

stomach, and small intestine. This drug is not effective in the colon because 

it does not induce colonic propulsive motility. 21 Its prokinetic effect in the 

stomach has been compared with that of cisapride and metoclopramide, and it 

appears to induce greater antral contractions in amplitude and frequency than 

those induced by cisapride and metoclopramide. 22 Erythromycin stimulates the 

interdigestive contractions of the migrating myoelectrical complex in the stomach 

and small intestine that usually occur during the fasted state. Therefore, 

when given to patients that have been fed, erythromycin may cause premature 

emptying of gastric solids into the small intestine, resulting in inadequate 

digestion and absorption of larger pieces of food. This may cause increased 

intestinal distress, thereby limiting its use. 

Acetylcholinesterase Inhibitors 

Acetylcholinesterase inhibitors (i.e., parasympathetics) are usually overlooked 

as a first-line therapy for motility disorders and are more commonly 

used for their antisecretory properties. Ranitidine and nizatidine are H 2-receptor 

antagonists but are also acetylcholinesterase inhibitors that increase the 

amount of acetylcholine available to bind smooth muscle at the muscarinic 

cholinergic receptors in the GI tract. 23 Prokinetic effects occur at the clinically 

recommended doses used for antisecretory activity. Both ranitidine and nizatidine 

are comparable to cisapride in stimulating gastric motor activity and 

increasing the rate of gastric emptying, making them the preferred antisecretory 

drugs for treating gastric ulcers. 23,24 Ranitidine and nizatidine have the 

strongest motility effect in the stomach but may also be effective in the small 

intestine and colon. They have both been shown to increase feline colonic 

smooth muscle contraction. 25 

Opioids 

Diphenoxylate hydrochloride, a meperidine derivative, and loperamide 

hydrochloride, a butyramide derivative, are used for their ability to act directly 

on the GI wall to increase the segmental contraction of the small and large 

bowel. Although not considered prokinetic drugs, they can help control diarrhea 

in dogs and cats because diarrhea is most commonly caused by hypomotility of 

the bowel. 

Benzamides 

Future prokinetic drugs that may become available soon in the United States 

are the new benzamide drugs. Tegaserod is from this new class of 5-HT 4–receptor 

agonists and is being evaluated in human clinical trials for its ability to increase 

colonic transit in patients with irritable bowel syndrome. 26 Potent prokinetic 

effects on canine colonic motility have been reported. 27 Gastric and intestinal 

effects have not been studied. Prucalopride is a potent partial benzamide agonist


Table 8. Immune-Modulating Drugs 


Metronidazole Dogs and cats: cholangitis—7.5 mg/kg Neurotoxicity at high doses or with liver 

PO q12–24h; bacterial overgrowth—10–15 mg/kg 

PO q12–24h; stomatitis—15 mg/kg PO q12–24h; 

Giardia, IBD—10–30 mg/kg PO q12–24h 

function impairment 

Prednisone Dogs and cats: 1–2 mg/kg PO q12h; Can cause polyuria/polydipsia, polyphagia, 

cats with eosinophilic enteritis: 2–3 mg/kg PO q12h gastric ulcers, Cushing’s syndrome 

Azathioprine Dogs: 50 mg/m2 (1–1.5 mg/kg) PO q24h for Can cause bone marrow suppression; CBC 

2 wk, then every other day for maintenance; monitoring required; lag period of weeks 

cats: 0.3–0.5 mg/kg PO q48h for full effect 

Cyclophosphamide Dogs: 50 mg/m2 PO four times per wk; cats: half Can cause bone marrow suppression; CBC 

of a 25-mg tablet PO four times per wk monitoring required; can cause vomiting/ 

diarrhea and hemorrhagic cystitis (dogs) 

Chlorambucil Dogs: 0.1–0.2 mg/kg PO q48h; cats: 0.25–0.5 

mg/kg PO q48–72h 

Can cause bone marrow suppression 

Tylosin Dogs and cats: 11–200 or 20–40 mg/kg PO q12h; Broad dose range with wide safety margin; 

1 /4–1 tsp with food q8–12h; 5–10 mg/kg PO each gram contains 100 mg tylosin; sprinkle 

q8–12h on food 

Sulfasalazine Dogs: 10–30 mg/kg PO q8h; cats: 20 mg/kg Can cause keratoconjunctivitis sicca; use 

or 250 mg PO q8h (three times), then q24h with caution in cats because of possible 


Mesalamine Dogs: 10–20 mg/kg PO q6–8h May decrease tear production in dogs 

Olsalazine Dogs and cats: 10–20 mg/kg PO q12–24h Not reported to decrease tear production 

in dogs 

at the 5-HT 4 receptor and is reported to stimulate 

colonic activity in dogs and cats and stimulate gastric 

emptying in dogs. 28 Other new benzamide prokinetic 

drugs such as mosapride citrate, cinitapride, clebopride, 

and renzapride are currently being developed and may 

become available in the United States in the future. 4 

Misoprostol 

Misoprostol may be used in dogs and cats with 

refractory constipation by initiating giant migrating 

complex pattern and increasing colonic propulsive 

activity as reported in dogs. 29 

ANTIMICROBIALS 

Use of antimicrobials to treat nonspecific gastroenteritis 

can cause more harm than good by negatively 

influencing the normal GI microflora. Misuse of 

antibiotics in animals with gastroenteritis can lead to 

disruption of the normal bacterial flora. This can cause 

increased bacterial colonization of the bowel and overgrowth 

of antibiotic-resistant pathogenic strains of bacteria 

(e.g., Clostridium perfringens, Clostridium difficile), 

which in turn can result in severe and chronic inflammation 

of the bowel. 30 Helicobacter pylori colonization occurs 

with high prevalence in the gastric mucosa of healthy as 

well as sick dogs and cats. 31 Infection causing clinical illness 

is not proven and is being investigated; indications 

for treatment are also being investigated. 32 

Proper use of antimicrobials for specific GI diseases 

includes adjunct treatment for secondary bacterial 

overgrowth caused by exocrine pancreatic insufficiency 

or inflammatory bowel disease (IBD; Table 7). Other 

indications for use are primary bacterial overgrowth of 

the proximal small intestinal bowel and diarrhea 

induced by Salmonella, Campylobacter, Clostridium, or 

enterotoxigenic E. coli, with evidence of these organisms 

on fecal culture, fecal cytology, or fecal enterotoxin 

assay. Bacterial adherence to villi on histopathologic 

examination of intestinal biopsies is another 

indication for antimicrobial treatment. Patients with 

bloody vomitus or bloody diarrhea or that have severe 

mucosal injury and mucosal barrier breakdown should 

also be placed on antimicrobial therapy. This includes 

patients with parvovirus, hemorrhagic gastroenteritis, 

salmon poisoning disease, and postchemotherapy complications. 

Translocation of normal bacterial flora from 

the intestinal lumen and into the bloodstream can lead 

to septicemia and death, particularly in immunosup-


pressed patients. Choosing the proper antibiotic therapy should be based on 

the known sensitivity of the antibiotic to the normal bacterial flora of the GI 

tract or the specific bacterial pathogen, if known. Stomach microflora has a 

transient population of clostridia, streptococci, lactobacilli, E. coli, and spirochetes. 

33 The proximal small intestinal bowel has low numbers of gram-positive 

bacteria, including streptococci and lactobacilli. Anaerobes and gram-negative 

bacteria are the predominate organisms in the distal small intestinal 

bowel and colon, with over 90% of anaerobic bacteria (i.e., Bacteroides, 

clostridia, lactobacilli) comprising the colonic environment. 33 Other considerations 

when choosing an antibiotic include using a bactericidal drug for severe 

hemorrhagic diarrhea or for immunosuppressed patients; using drugs that can 

be given by parenteral route in patients that are vomiting, septic, or unconscious; 

choosing an antibiotic based on culture and sensitivity results when 

available; and being aware of toxic side effects (e.g., nephrotoxicity of an 

aminoglycoside in dehydrated animals). 

IMMUNE-MODULATING DRUGS 

Inflammatory or immune-mediated diseases of the bowel are treated by 

immunosuppressive therapy. In dogs and cats, IBD is the most commonly diagnosed 

disease by endoscopic biopsy or surgical biopsy of the GI tract. Treatment 

is directed at reducing the inflammation and implementing a controlled diet 

(Table 8). 34–36 Drugs that can effectively help decrease the inflammatory response 

in the GI tract are metronidazole, salicylates, prednisone, azathioprine, cyclophosphamide, 

chlorambucil, and potentially cyclosporine. 36 Tylosin, a macrolide-like 

antibiotic used for bacterial overgrowth, has also been reported to be effective in 

some patients with IBD, although the exact mechanism of action is unknown. 36 It 

is available in a powder and can be sprinkled on the animal’s food. 

Metronidazole 

Metronidazole is an antibiotic with sensitivity to anaerobic bacteria, although it 

does not cause detrimental alteration of normal bacterial flora. It also has immunemodulating 

properties that suppress cell-mediated responses, is an antiprotozoal, 

and has positive effects on brush-border enzyme levels and the uptake of nutrients 

by the intestine (e.g., glucose, amino acids). 37 It is unknown which of its actions is 

responsible for its efficacy in treating IBD. Metronidazole can be effective in mild 

cases of IBD and provide good control. In moderate to severe cases, it can be used 

as a combination therapy with lower doses of prednisone. 

Salicylates 

Sulfasalazine, a salicylate, is used specifically for inflammation of the colon 

and is the treatment of choice for chronic colitis. This drug contains sulfapyridine 

and 5-aminosalicylate joined by an azo bond that is separated in the colon. 

The 5-aminosalicylate component, which acts as a local suppressor of inflammation, 

is an NSAID that inhibits cyclooxygenase and lipoxygenase activity 

inhibiting prostaglandin and leukotriene synthesis. In mild to moderate cases of 

colonic IBD, this drug can be beneficial when used alone. In more severe cases, 

this drug should be used in combination with metronidazole or prednisone. 

Side effects include anorexia, vomiting, diarrhea, and keratoconjunctivitis sicca 

(which can lead to corneal ulceration); in cats, anemia has been reported. 

Preparations of 5-aminosalicylate without the sulfapyridine component 

(mesalamine, olsalazine) may prevent keratoconjunctivitis sicca and are commonly 

used in human medicine for long-term treatment. 38 However, 

mesalamine may decrease tear production in dogs.


Corticosteroids 

Prednisone is a corticosteroid that is a rapid and potent 

suppressor of the cell-mediated response and the humoral 

response. Corticosteroids are considered the treatment of 

choice in cases of moderate to severe IBD (lymphocytic–plasmacytic) 

and are usually effective when metronidazole is not. 

Side effects include gastric, duodenal, or colonic ulceration 

and iatrogenic hyperadrenocorticism. Dexamethasone should 

be avoided because of its prolonged effects on the hypothalamic–pituitary 

axis. Prednisone can be given daily and then 

tapered to alternate-day maintenance therapy when clinical 

signs resolve. Patients that have severe side effects on alternate-day 

therapy can be given an alternative therapy alone or 

in combination with lowered doses of prednisone. Budesonide, 

a corticosteroid that is given orally and has topical 

effects in the small and large bowel with minimal systemic 

absorption, has been used successfully in humans with ulcerative 

colitis. 39 It is currently being investigated for its use in 

dogs with IBD. Azathioprine, a suppressor of the antigeninduced 

lymphocyte transformation, is a commonly used 

alternative. Azathioprine can be given alone or in combination 

with lower doses of prednisone. It is usually given daily 

for 2 weeks and then tapered to every other day. Side effects 

include anorexia, vomiting, diarrhea, and bone marrow suppression. 

Mild bone marrow suppression is common and not 

of great concern. Although rare, severe suppression occurs 

more commonly in cats than in dogs and is most often seen 

early in the treatment protocol. 36 Pancreatitis and hepatotoxicity 

have also been reported. 36 Patient monitoring with routine 

complete blood cell count analysis is indicated. 

Chemotherapeutic Agents 

Patients with severe and refractory IBD may respond to 

cyclophosphamide. Cyclophosphamide is a chemotherapeutic 

agent that is a potent immunosuppressor. 36 Side effects include 

vomiting, diarrhea, sterile hemorrhagic cystitis (in dogs), and 

bone marrow suppression. It is given daily for 4 consecutive 

days and then discontinued for 3 days each week, making this 

drug easier than azathioprine to administer to cats. The patient 

must be monitored closely with routine complete blood cell 

count analyses. Chlorambucil is an oral chemotherapeutic drug 

with cytotoxic effects similar to those of cyclophosphamide 

(although not as potent) but may be helpful in some refractory 

cases of IBD. 36 Side effects of bone marrow suppression are 

minimal when using chlorambucil compared with cyclophosphamide, 

and GI signs are usually eliminated by alternate-day 

dosing. Cyclosporine, a T-cell suppressor drug available in oral 

preparation, has not been studied in dogs and cats with IBD 

but has been shown to be an effective treatment in humans 

with severe, unresponsive IBD. 36 Although it is very expensive, 

cyclosporine has been used to treat other immune-mediated 

diseases in dogs and cats and could be considered in severe cases. 

Side effects include vomiting, diarrhea, pancreatitis, and bone


marrow suppression. It is paramount to monitor closely for 

these side effects, and the drug should be withdrawn if these 

effects occur. Measuring serum cyclosporine levels is recommended 

to achieve therapeutic levels and avoid toxicity. It is 

available in a micropulverized compound because of reportedly 

poor oral absorption. Bioavailability of oral doses varies 

with individual patients. 

REFERENCES 

1. Boothe DM: Small Animal Clinical Pharmacology and Therapeutics. 

Philadelphia, WB Saunders Co, 2001, pp 483–488. 

2. Boothe DM: Gastrointestinal pharmacology. Vet Clin North Am Small Anim 

Pract 2:343–376, 1999. 

3. Burrows CF: Metoclopramide. JAVMA 183:1341–1343, 1983. 

4. Dowling PM: Life after cisapride: Prokinetic drugs for small animals. 

Vet Med 95(9):678–685, 2000. 

5. Sanwald-Ducray P, Dow J: Prediction of the pharmacokinetic parameters of 

reduced-dolasetron in man using in vitro–in vivo and interspecies allometric 

scaling. Xenobiotica 27(2):189–201, 1997. 

6. Ogilvie G: Dolasetron: A new option for nausea and vomiting. JAAHA 

36:481–483, 2000. 

7. Parkman HP, Pagaw AP, Ryan JP: Ranitidine and nizatidine stimulate 

antral smooth muscle contractility via excitatory cholinergic mechanisms. 

Dig Dis Sci 43:497–505, 1998. 

8. El-Omar E, Banerjee S, Wirz A, et al: Marked rebound acid hypersecretion 

after treatment with ranitidine. Am J Gastroenterol 91:355–359, 1996. 

9. Lampkin TA, Ouelleet D, Hak LJ, et al: Omeprazole: A novel antisecretory 

agent for the treatment of acid-peptic disorders. Ann Pharmacother 

24:393–402, 1990. 

10. Jenkins CC, Denovo RC: Omeprazole: A potent antiulcer drug. Compend 

Contin Educ Pract Vet 13(10):1578–1582, 1991. 

11. Guilford WG, Strombeck DR: Chronic gastric disease, in Guilford 

WG, Center SA, Strombeck DR, et al (eds): Strombeck’s Small Animal 

Gastroenterology, ed 3. Philadelphia, WB Saunders Co, 1996, pp 

275–302. 

12. Wolfe MM, Soll AH: The physiology of gastric acid secretion. N Engl J 

Med 319:1707–1715, 1988. 

13. Wilke JR, Turner JC: The use of adsorbents to treat gastrointestinal 

problems in small animals. Semin Vet Med Surg Small Anim 

2(4):266–273, 1987. 

14. Ericsson CD, Evans DG, Dupont HL, et al: Bismuth subsalicylate 

inhibits activity of crude toxins of Escherichia coli and Vibrio cholerae. J 

Infect Dis 136:693–696, 1977. 

15. Hall JA, Washabau RJ: Gastrointestinal prokinetic therapy: Dopaminergic 

antagonist drugs. Compend Contin Educ Pract Vet 19(2):214–221, 1997. 

16. FitzSimons H: Pharm profile: Cisapride. Compend Contin Educ Pract Vet 

21(4):324–327, 1999. 

17. Dowling PM: Life after cisapride: Prokinetic drugs for small animals. 

Vet Med 95(9):678–685, 2000. 

18. Tonini M, DePonti F, Di Nucci A, Crema F: Review article: Cardiac 

adverse effects of gastrointestinal prokinetics. Aliment Pharmacol Ther 

13(12):1585–1591, 1999. 

19. Peeters TL: Erythromycin and other macrolides as prokinetic agents. 

Gastroenterology 105:1886–1899, 1993. 

20. Hall JA, Washabau RJ: Gastrointestinal prokinetic therapy: Motilinlike 

drugs. Compend Contin Educ Pract Vet 19(3):281–288, 1997. 

21. Inatomi N, Satoh T, Satoh H, et al: Comparison of the motor-stimulating 

action of EM523, an erythromycin derivative and prostaglandin F2 

(alpha) in conscious dogs. Jpn J Pharmacol 63:209–217, 1993. 

22. Itoh Z, Nakaya M, Suzuki T, et al: Erythromycin mimics exogenous 

motilin in gastrointestinal contractile activity in the dog. Am J Physiol 

247:G688–G694, 1984.


23. Mizumoto A, Fujimura M, Iwanaga Y, et al: Anticholinesterase activity 

of histamine H 2-receptor antagonists in the dog: Their possible role in 

gastric motor activity. J Gastrointest Motil 2(4):273–280, 1990. 

24. Ueki S, Seiki M, Yoneta T, et al: Gastroprokinetic activity of nizatidine, 

a new H 2-receptor antagonist and its possible mechanism of action in 

dogs and rats. J Pharmacol Exp Ther 264(1):152–157, 1993. 

25. Washabau RJ, Pitts M, Hasler A, et al: Nizatidine and ranitidine stimulate 

feline colonic smooth muscle contraction (abstract). Proc ACVIM:739, 1996. 

26. Prather CM, Camilleri M, Zinsmeister AR, et al: Tegaserod accelerates 

orocecal transit in patients with constipation-predominant irritable 

bowel syndrome. Gastroenterology 118:463–468, 2000. 

27. Nguyan A, Camilleri M, Kort LJ: SD2HTF919 stimulates canine 

colonic motility and transit in vivo. J Pharmacol Exp Ther 

280:1270–1276, 1997. 

28. Briejer MR, Ghoos E, Eelen J, et al: Serotonin 5H mediates the 

R093877 induced changes in contractile patterns in the canine colon. 

Gastroenterology 112:A705, 1997. 

29. Washabau RT: What’s new in gastrointestinal prokinetic therapy? Proc 

19 th ACVIM:538–539, 2001. 

30. Jergens AE: Rational use of antimicrobials for gastrointestinal disease in 

small animals. JAAHA 30:123–131, 1994. 

31. Yamasaki K, Suematsu H, Takahashi T: Comparison of gastric lesions in 

dogs and cats with and without gastric spiral organisms. JAVMA 

212(4):529–533, 1998. 

32. Simpson K, Neiger R, DeNovo R, Sherding R: The relationship of 

Helicobacter spp. infection to gastric disease in dogs and cats. J Vet 

Intern Med 14:223–227, 2000. 

33. Strombeck D: Microflora of the gastrointestinal tract and its symbiotic 

relationship with the host, in Guilford WG, Center SA, Strombeck DR, 

et al (eds): Strombeck’s Small Animal Gastroenterology, ed 3. Philadelphia, 

WB Saunders Co, 1996, pp 14–19. 

34. Leib MS, Hiler LA, Roth L, et al: Plasmacytic-lymphocytic colitis in 

the dog. Semin Vet Med Surg 4:241–246, 1989. 

35. Nelson RW, Stookey LJ, Kazacos E: Nutritional management of idiopathic 

chronic colitis in the dog. J Vet Intern Med 2:133–137, 1988. 

36. Guilford WG: Idiopathic inflammatory bowel disease, in Guilford WG, 

Center SA, Strombeck DR, et al (eds): Strombeck’s Small Animal Gastroenterology, 

ed 3. Philadelphia, WB Saunders Co, 1996, pp 451–486. 

37. Sanyal SN, Jamba L, Channan M: Effect of the antiprotozoal agent 

metronidazole (Flagyl) on absorptive and digestive functions of the rat 

intestine. Ann Nutr Metab 36:235–243, 1992. 

38. Brzezinski A, Rankin GB, Seidner DL, et al: Use of old and new oral 5aminosalycylic 

acid formulations in inflammatory bowel disease. Cleve 

Clin J Med 62(5):317–323, 1995. 

39. Filip B, Schmit A, D’Haens G, et al: Budesonide in collagenous colitis: 

A double-blind placebo-controlled trial with histologic follow-up. Gastroenterology 

122:20–25, 2002. 

ARTICLE 

CE 

#2 CE TEST 

The article you have read qualifies for 1.5 contact 

hours of Continuing Education Credit from 

the Auburn University College of Veterinary Med- 

icine. Choose the best answer to each of the follow- 

ing questions; then mark your answers on the 

postage-paid envelope inserted in Compendium. 

1. Which of the following emetics acts on α 2 receptors and is 

considered the emetic of choice in cats? 

a. apomorphine d. warm water 

b. xylazine e. saline 

c. hydrogen peroxide


2. Which of the following emetics can cause fatal aspiration? 

a. apomorphine d. warm water 

b. xylazine e. saline 

c. hydrogen peroxide 

3. Which of the following antiemetic drugs is the most potent? 

a. metoclopramide 

b. domperidone 

c. prochlorperazine 

d. ondansetron 

e. diphenhydramine hydrochloride 

4. Which of the following drugs exerts its antiemetic effects by 

both central and peripheral actions? 

a. metoclopramide 

b. chlorpromazine 

c. prochlorperazine 

d. ondansetron 

e. diphenhydramine hydrochloride 

5. Which of the following gastric antisecretory drugs is considered 

the most potent reducer of gastric acidity? 

a. famotidine d. nizatidine 

b. ranitidine e. omeprazole 

c. cimetidine 

6. Which of the following drugs has antisecretory properties as 

well as cytoprotective properties and is used for the prevention 

and/or treatment of gastric ulcers? 

a. misoprostol 

b. aluminum magnesium hydroxide 

c. magnesium hydroxide 

d. calcium carbonate 

e. sucralfate 

7. Which of the following protectant and adsorbent drugs 

binds bile salts and can potentially be used for the treatment 

of certain drug intoxications? 

a. kaolin–pectin d. bismuth subcarbonate 

b. cholestyramine e. activated charcoal 

c. bismuth salts 

8. Which of the following prokinetic drugs is comparable to 

cisapride with motility effect on the stomach? 

a. metoclopramide d. erythromycin 

b. tegaserod e. c and d 

c. ranitidine 

9. Which of the following antimicrobials is used for antimicrobial 

and antiinflammatory properties in the treatment of IBD? 

a. amoxicillin d. sulfasalazine 

b. enrofloxacin e. c and d 

c. metronidazole 

10. Which of the following drugs could be used in combination with 

prednisone to potentially lower the dose of prednisone needed 

to treat moderate to severe lymphocytic–plasmacytic IBD? 

a. cyclophosphamide d. chlorambucil 

b. azathioprine e. b and c 

c. metronidazole

cearticle #2 ce test - VetLearn.com

Create successful ePaper yourself

Delete template?

Save as template?