Page 468 - Small Animal Internal Medicine, 6th Edition

440 PART III Digestive System Disorders

thus protecting it. It also inhibits peptic activity and may reasonable if diarrhea causes excessive fluid or electrolyte
alter prostaglandin synthesis and the actions of endogenous losses or owners demand control of the diarrhea at home.
VetBooks.ir sulfhydryl compounds. There is no evidence that combining Opiates (Table 28.6) increase resistance to flow by augment-
ing segmental contraction. They are more effective than
sucralfate with PPIs or H 2 receptor antagonists is beneficial.
Because sucralfate may adsorb other drugs, slowing their
create ileus. Both classes of drugs have antisecretory effects.
absorption, other orally administered drugs ideally should parasympatholytics, which paralyze intestinal motility and
be given 1 to 2 hours before or after sucralfate administra- Because cats do not tolerate narcotics as well as dogs, opiates
tion. Sucralfate can cause constipation. should be avoided in cats although loperamide may be used
Misoprostol (Cytotec) is a prostaglandin E 1 analog carefully.
designed to prevent NSAID-induced gastroduodenal ulcer- Loperamide (Imodium) theoretically increases risk for
ation, but it can be used to treat ulcers. Misoprostol does not bacterial proliferation in the intestinal lumen; however, this
appear to be as effective in preventing NSAID-induced is rarely clinically important. An overdose can cause narcotic
ulcers in dogs as it is in people, and PPIs appear to be as intoxication (i.e., collapse, vomiting, ataxia, hypersalivation),
effective as misoprostol. The major adverse effects of miso- which requires treatment with narcotic antagonists. Dogs
prostol seem to be abdominal cramping and diarrhea, which deficient in P-glycoprotein (i.e., those with MDR gene muta-
usually disappear after 2 to 3 days of therapy. It is also an tion [Collies, Australian Shepherds, etc.]) are at greater risk
abortifacient. for adverse central nervous system signs.
Diphenoxylate (Lomotil) is similar to loperamide but
somewhat less effective. It has more potential for toxicity
INTESTINAL “PROTECTANTS” than loperamide. It may have some antitussive properties.
Rarely a dog responds to it but not to loperamide. This drug
Intestinal protectants include drugs and inert adsorbents should not be used in cats.
such as kaolin, pectin, and barium sulfate contrast media. Drugs that shorten transit time (prokinetic drugs) empty
Many people believe that inert adsorbents hasten clinical the stomach or increase intestinal peristalsis or both. Meto-
relief in animals with minor inflammation, possibly because clopramide causes gastric prokinesis, enhancing gastric
they coat the mucosa or adsorb toxins. They make loose emptying of fluids. It can be administered orally or parenter-
stools more normal simply by increasing fecal particulate ally. Adverse effects are mentioned under the section on
matter. Inert adsorbents do not have proven efficacy in the antiemetics. Cisapride is a 5-HT 4 agonist that stimulates
treatment of gastritis or enteritis. It is inappropriate to rely normal motility from the lower esophageal sphincter to the
on these drugs alone in very sick animals. anus. It is usually effective unless the tissue has been irrepa-
rably damaged (e.g., megacolon in cats). Primarily used for
the treatment of constipation, it may also be used for the
DIGESTIVE ENZYME SUPPLEMENTATION

Pancreatic enzyme supplementation is indicated to treat exo-
crine pancreatic insufficiency (EPI). Empirical use as a thera- TABLE 28.6
peutic trial for presumptive EPI is a poor approach. There are
many products that vary greatly in potency. Although pills Selected Drugs Used for Symptomatic Treatment
may work, enteric-coated pills are particularly ineffective. of Diarrhea
Powdered preparations tend to be more effective; Viokase-V DRUG DOSAGE*
(A.H. Robins Co.) and Pancreazyme (Daniels Pharmaceuti-
cals) seem to be particularly efficacious. The powder should Intestinal Motility Modifiers (Opiates)
be mixed with food (approximately 1-2 teaspoons per meal). Diphenoxylate (Lomotil) 0.05-0.2 mg/kg PO q8-12h
Incubating the mixture before feeding is not beneficial. Fat is (dogs)
the main nutrient that must be digested in animals with exo- Loperamide (Imodium) 0.12 mg/kg PO q8-12h
crine pancreatic insufficiency, and feeding a low-fat diet may (dogs)
ameliorate diarrhea. Antacid and/or antibiotic therapy has 0.08-0.16 mg/kg PO q12h
anecdotally helped prevent gastric acidity or small intestinal (cats)
bacteria from reducing enzyme supplementation effective-
ness. Occasionally, stomatitis or diarrhea develops in dogs Antiinflammatory/Antisecretory Drug
†
receiving excessive enzyme supplementation. Bismuth subsalicylate 1 mL/kg/day PO divided
(Pepto-Bismol, q8-12h (dogs) for 1-2 days
Kaopectate)
MOTILITY MODIFIERS
PO, Orally.
*Dosages are for both dogs and cats unless otherwise specified.
Drugs that prolong intestinal transit time are used to symp- † This drug contains salicylate and can be nephrotoxic if combined
tomatically treat diarrhea. Infrequently needed, they are with other nephrotoxic drugs.