Page 401 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

368 SECTION | IV Drugs of Use and Abuse

VetBooks.ir Diagnosis and Management determined that a single dose of activated charcoal was as
effective as multiple doses and produced fewer adverse
Diagnosis of NSAID toxicosis is often based on history
effects. Sorbitol plus activated charcoal increased rate of
and clinical signs. Serum or plasma testing for NSAID
drugs is available at many veterinary laboratories and elimination but did not change the maximum circulating
concentration compared to activated charcoal alone, but the
human hospitals. Serum drug concentrations are unlikely
addition of sorbitol did not cause clinically evident adverse
to be useful in management, but some reference values
effects.
are listed in the toxicokinetics portion of this section.
Intravenous lipid infusion has been used to treat ibu-
Endoscopy is the most sensitive test for gastric ulcera-
profen and naproxen overdoses in dogs by providing a
tion, although occasionally the ulcer will not be visible.
lipid compartment and enhancing elimination (Bolfer
Anesthesia is required, thus the patient must be stabilized.
et al., 2014; Herring et al., 2015). Lipid emulsion therapy
Survey radiographs are not usually useful. If there is gas-
was used in a dog that ingested a high dose of ibuprofen
trointestinal perforation, then poor visualization of serosal
(.1800 mg/kg) and became comatose within 30 min of
surfaces, peritoneal effusion, free gas in the peritoneal
arrival to the veterinary clinic (Bolfer et al., 2014). The
cavity, and intestinal ileus are often noted (Godshalk
patient showed slight improvement within 3 h, and was
et al., 1992; Talcott, 2006). Large ulcers have been identi-
alert and responsive 13 h after lipid administration, but had
fied on contrast radiographs; however, if perforation is
evidence of coagulopathy. The dog survived and was dis-
present, barium sulfate will complicate peritonitis, thus a
charged after 5 days of hospitalization, and appeared to be
water soluble agent is preferred. Ulcers can be detected
completely recovered on examination 1 week later. Three
using ultrasound in an animal given water by stomach
dogs that ingested between 60 and 200 mg/kg of naproxen
tube. The gastric wall is thickened with a loss of the nor-
were given intravenous lipid infusion (Herring et al., 2015);
mal five-layer structure, disruption of the mucosa, and gas
circulating naproxen concentrations declined quickly. After
bubble formation. Increased fluid in the abdomen is seen
treatment, dogs developed relatively mild clinical signs,
in the case of peritonitis due to perforation.
including azotemia in one and melena in another, and all
Renal papillary damage can be diagnosed in humans,
were discharged without further complications.
horses, and foals using ultrasound (Brix, 2002; Roder,
Animals should be monitored for hydration, electro-
2004a). Computed tomography has been used to diagnose lyte imbalances, acid base imbalances, blood glucose,
renal papillary necrosis in humans, and magnetic reso- liver enzymes, BUN, creatinine, body temperature, and
nance imaging has been used experimentally (Brix, 2002). blood pressure. Deviations from expected values can be
Animals on NSAID therapy should be closely moni- corrected as needed. Fluid therapy is needed to correct
tored for adverse effects: attitude, appetite, hydration, dehydration, hypotension, electrolyte imbalances, and
electrolyte status, urine concentrating ability, urine pro- improve renal perfusion. It has been suggested that fluids
tein concentrations, BUN, creatinine, and liver enzymes be given at twice the maintenance rates. Villar et al.
can be monitored (Villar et al., 1998; Roder, 2004a). (1998) recommended 0.9% saline, or 0.45% saline plus
When animals present with adverse effects attributable to 2.5% dextrose, in hypoglycemic animals, given at a rate
NSAIDs, administration of the drug should be discontinued. of 120 mL/kg/day plus estimated fluid losses over a 48-
Gastric emptying is appropriate for animals that have to 72-h period. Lactated Ringers solution can contribute
ingested large quantities of NSAIDs but are not yet showing to electrolyte imbalances and, thus, should be used with
clinical signs (Kore, 1990). Emetics are sometimes used for caution. Dopamine at a dose of 2.5 μg/kg/min, or dobuta-
large single ingestions, although they are contraindicated in mine at 2.5 mg/kg/min, can be given to increase renal per-
animals with severe CNS suppression. Gastric lavage can be fusion (Kore, 1990). Diuretics can predispose animals to
performed in the anesthetized, intubated animal (Cathers dehydration and subsequent renal hypoperfusion and,
et al., 2000). Activated charcoal and cathartics are given thus, should be avoided (Albretsen, 2002). Sodium bicar-
after gastric emptying or if the animal presents later. bonate is used cautiously to treat acidosis and for ion trap-
Repeated activated charcoal administration has been recom- ping (Murphy, 1994; Roder, 2004a). Urine alkalization
mended for various reasons. Some tablets are sustained- for ion trapping is sometimes useful with salicylates, aspi-
release, and regular tablets can form concretions in the stom- rin, and ibuprofen, but urinary pH must exceed 7.5 8to
ach and have delayed absorption. Furthermore, activated increase naproxen secretion.
charcoal prevents enterohepatic cycling, which is the cause Gastric lavage with iced saline or water has been
of a prolonged half-life of ibuprofen and other NSAIDs in recommended for severe and continued gastric bleeding,
dogs. However, a report looked at the effect of activated but the efficacy of this treatment is questionable, and sur-
charcoal, activated charcoal plus sorbitol as a cathartic, or gical correction is often required (Wallace et al., 1997).
multiple doses of activated charcoal on a moderate overdose Severe anemia is treated with transfusions or blood substi-
of carprofen in dogs (Koenigschof et al., 2015), and tutes (Murphy, 1994; Sellon, 2006). Acute loss of greater