Page 641 - Fluid, Electrolyte, and Acid-Base Disorders in Small Animal Practice

628 SPECIAL THERAPY

association of an adverse stimulus with a novel diet, so stimulant at a dose of 15 to 30 mg by mouth once daily
that when the animal is offered the diet again it associates (cats can be dosed at 3.75 mg every 48 to 72 hours). 58 In
the food with feelings of ill health and refuses to eat it. humans antidepressants are commonly tapered in consid-
If instituting a particular diet as part of long-term patient eration of antidepressant discontinuation syndrome, the
treatment, it should not be introduced during hospitali- significance of which has not been well characterized in
zation if at all possible. Introducing the diet when the pets, but its consideration may be advised. 98
animal is feeling better, so that it associates a feeling of Other drugs, including prednisone (0.25 to 0.5 mg/
well-being with the new food, increases the probability kg body weight every other day) have been used to stim-
of success. ulate appetite. 66 Although any of these drugs may be
Learned aversions in veterinary patients have not been effective in isolated patients, none have been tested in
studied in any systematic way, but they may occur. In fact, controlled trials in veterinary medicine, and none have
this may be one reason some veterinary therapeutic diets been demonstrated to be of consistent value. The greatest
are difficult to institute in sick animals. A variety of danger of pharmacologic appetite stimulation is that its
chemicals have been used to stimulate appetite. Two use may give the false impression that adequate
commonly recommended pharmacologic agents are B nutritional support is being provided. These drugs often
vitamins and appetite-stimulating drugs. There is no evi- stimulate animals to eat small meals immediately, 66 and
dence that administration of any of the individual B the clinician may conclude that food intake is adequate.
vitamins or combinations of them stimulates food intake Unless the total quantity of food eaten is measured, how-
in sick dogs or cats. Sick animals may have vitamin ever, it cannot be determined if the animal continues to
deficits, but they also have energy and other nutrient eat over the remainder of the 24-hour period. Use of
deficits that must be addressed simultaneously if these drugs should be restricted to animals in which food
nutritional support is to be effective. intake is being measured because of the inconsistent
Drugs used to stimulate appetite include the benzodi- response to their use and the probability of delay of
azepine derivatives, oxazepam (Serax, Wyeth, Madison, appropriate nutritional support.
N.J.) and diazepam (Valium, Roche, Basel, Switzerland),
the antiserotonergic agent, cyproheptadine (Periactin, SYRINGE FEEDING
Merck, Whitehouse Station, N.J.) and more recently
the antidepressant agent, Mirtazapine (Remeron, Merck, Syringe feeding may provide some nutrition, but is not
Whitehouse Station, N.J.). 66 However, it should be recommended due to the stress imposed on the patient
stressed that these drugs are only short-term options, and the increased risk of aspiration pneumonia, particu-
and should not be used unless enteral nutrition support larly in critically ill or mentally depressed patients. In
in the form of a temporary feeding tube is not an option. addition, syringe feeding is time-consuming for the vet-
These medications should not be used for more than 24 erinary staff and the volume of food often negates the
to 48 hours in patients that are not consuming adequate act of syringe feeding (e.g., a 10-lb cat would need to
nutrition. be force fed 24 to 10 mL syringes of food; a 60-lb dog
Benzodiazepines are effective appetite stimulants in needing approximately 1000 calories daily would need
healthy dogs and cats. 31 No controlled studies are avail- to be force fed 20 to 60 mL syringes of food). Lastly,
able in veterinary patients for any of these compounds, the act of force-feeding a sick patient can result in the
which appear to be more effective for psychogenic than development of food aversions. If all attempts to induce
for pathologic anorexia. Psychogenic, or fear-induced, the animal to eat voluntarily fail, an indwelling enteral
anorexia is common in hospitalized dogs and cats because feeding tube should be considered in place of syringe
of the strange surroundings, the stress of disease and feeding.
trauma, and the unfamiliar human beings caring for OROGASTRIC FEEDING
them. Administration of 0.1 to 0.2 mg/kg body weight
of diazepam intravenously, or 2.5 mg per cat per feeding TUBES FOR NEONATAL
of oxazepam orally, has been recommended to stimulate NUTRITION
food intake in these settings. 66 The recommended dosage
of cyproheptadine for cats is 2 mg orally, two to three Neonates may be fed by passing a tube through the
times daily. Although sometimes effective for psycho- mouth or nose into the stomach for each feeding
genic anorexia, these drugs do not appear to be effective (Figure 26-3). To pass an orogastric feeding tube, 24,35,94
for pathologic, disease-induced anorexia. Moreover, their first measure the distance from the mouth to the tenth rib
sedative effects are undesirable in depressed animals, and and mark the tube with permanent marker. Lubricate the
they are contraindicated in patients with liver disease. 95 end of the tube with a water-soluble lubricant. Pass the
Mirtazapine (Remeron) is a tricyclic antidepressant tube through the mouth and into the pharynx. Hold
and an antiemetic in human medicine. It has been more the animal’s head at the normal angle of articulation to
recently used in canine oncology patients as an appetite minimize the possibility of endotracheal intubation.