Page 1491 - Cote clinical veterinary advisor dogs and cats 4th

756.e8 Paraquat and Diquat Toxicoses

TREATMENT ulcers (p. 380), and renal complications • Concentration of diquat in most ready-
(p. 23) as needed to-use weed and grass killer products is
VetBooks.ir Because no antidote exists for either substance, selenium, niacin, riboflavin, N-acetylcysteine, are highly unlikely with casual exposure
Treatment Overview
< 1%. Systemic effects from these products
○ A variety of compounds such as vitamin E,
ascorbic acid, and clofibrate have been used
(e.g., dog walking through the sprayed area
treatment is symptomatic and supportive.
Acute General Treatment in an attempt to counteract the damage done when it was still wet or dog licking the grass
by the free radicals in the lung. None have
after spray) unless large amounts have been
• Decontamination of the animal (p. 1087) shown to be clinically effective. ingested from the container. Such casual
○ Paraquat ○ Positive-pressure ventilation (p. 1185) may exposures result in mild self-limited GI signs.
Emesis: induction of vomiting (p. 1188) be used, but lung lesions may become (or
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as soon as possible after ingestion, even may already be) irreversible. Prevention
though paraquat can be irritating/cor- ○ Pulse therapy of methylprednisolone Keep animals away from all herbicides until
rosive to the esophagus; the possible and cyclophosphamide (± continuous completely dry.
benefits of early removal outweigh the dexamethasone) was shown to reduce
potential risks mortality rates for humans with severe Technician Tips
Activated charcoal 1 g/kg PO can be paraquat toxicosis from > 85% in control Obtain original container and concentration the
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used as an adsorbent. Most effective groups to < 35% in pulse-treated groups. animal was exposed to. Use gloves, especially
within 2-4 hours when decontaminating dermal exposures of
Bathe patient if there is any dermal Behavior/Exercise paraquat.
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exposure. Wear gloves. Restrict exercise until resolution of signs.
With ocular exposures, irrigate eyes with Client Education
■
copious amounts of tepid water for at Possible Complications Follow label directions on all herbicides.
least 15-30 minutes. • Paraquat: pulmonary edema and hemorrhage,
○ Diquat emphysema, kidney injury, respiratory failure, SUGGESTED READING
Induction of vomiting is usually not esophageal stricture
■ O’Sullivan SP: Paraquat poisoning in the dog. J Small
recommended unless the patient has • Diquat: kidney injury, esophageal stricture Anim Pract 30(6):361-364, 1989.
been exposed to a very large amount.
With low-concentration products, Recommended Monitoring ADDITIONAL SUGGESTED
dilution is preferred. • Paraquat: serial thoracic radiographs and READINGS
Activated charcoal for large exposures blood gases (or pulse oximetry) for pulmo-
■ CDC Facts About Paraquat (website). https://
Bathe dogs with dermal exposure nary function; renal and liver values
■ emergency.cdc.gov/agent/paraquat/basics/facts.asp.
Ocular exposures: same treatment as • Diquat: renal values
■ Shuler CM, et al: Retrospective case series of suspected
for paraquat intentional paraquat poisonings: diagnostic find-
• Supportive care PROGNOSIS & OUTCOME ings and risk factors for death. Vet Hum Toxicol
○ IV fluids to maintain hydration, promote 46(6):313-314, 2004.
elimination, maintain cardiovascular • Paraquat: poor prognosis for animals showing
function respiratory signs RELATED CLIENT EDUCATION
○ Control pain: buprenorphine 0.01- • Diquat: excellent prognosis with low SHEET
0.02 mg/kg SQ, IM, or IV, fentanyl patch concentration and small exposures; with
○ Control vomiting with maropitant large exposures, can be good with early and How to Induce Vomiting
1 mg/kg SQ q 24h or metoclopramide aggressive treatment
0.1-0.4 mg/kg SQ or IM q 6h AUTHOR: Irina D. Meadows, DVM, DABT
○ Supplemental oxygen administration is PEARLS & CONSIDERATIONS EDITOR: Tina Wismer, DVM, MS, DABT, DABVT
contraindicated because oxygen enhances
the formation of free radicals in the lung Comments
and causes further pulmonary injury. • Paraquat LD50 (dogs, oral): 25-50 mg/kg
○ Treatment of seizures (p. 903), secondary • Diquat LD50 (dogs, oral): 100 mg/kg
infections, oral ulcers (p. 1002), gastric

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