If you have any reason to suspect your pet has ingested something toxic, please contact your veterinarian or one of the other resources listed:
ASPCA Animal Poison Control Center 24-hour hotline at (888) 426-4435
• Pet Poison Helpline® 24-hour animal poison control service at (855) 764-7661

Metronidazole

metronidazole copy

Generic Name: Metronidazole
Brand Name: Flagyl

Metronidazole is an antibiotic used in both human and veterinary medicine to treat a variety of disease states, including chronic diarrhea.

Toxicity often occurs from intentional dosing at levels greater than 30 mg/kg/day. While much of the literature warns of potential toxicity at doses greater than 60 mg/kg/day, there is an increasing incidence of toxicity occurring at lower doses. Beyond dosing, there seems to be a positive correlation of prolonged therapy (3 weeks and longer) and toxicosis.

Signs and symptoms of toxicity: difficulty walking, rapid eye movements, head-tilt, joint knuckling, disorientation, refusal to eat, vomiting, extreme fatigue, stiffness and seizures.

Toxic consumption: The referenced toxic threshold is 60 mg/kg/day (values listed in chart below). As previously mentioned, chronic therapy with lower doses may result in toxicosis.

Please note that these values are total daily consumption.

Dogs: Metronidazole Toxic Consumption
X-Small
Yorkie, Chihuahua
Small
Pug, Boston Terrier, Poodle
Medium
Beagle, Scottish Terrier
Large
Boxer, Cocker Spaniel
X-Large
Labrador & Golden Retrievers, German Shepherd
XX-Large
Great Dane, St. Bernard
1 – 10 lbs.
(0.45 – 4.6 kg)
11 – 25 lbs.
(5 – 11.4 kg)
26 – 40 lbs.
(11.8 – 18.2 kg)
41 – 70 lbs.
(18.6 – 31.8 kg)
71 – 90 lbs.
(32.3 – 40.9 kg)
91 – 110 lbs.
(41.4 – 50 kg)
dog1 dog2 dog3 dog4 dog7 dog6
> 27 mg > 300 mg > 708 mg > 1116 mg > 1938 mg > 2484 mg

References:
– Evans J, Levesque D, Knowles K, et al. Diazepam as a treatment for metronidazole toxicosis in dogs: A retrospective case study of 21 cases. J Vet Intern Med 2003;17:304-10.
– Metronidazole. In: Plumb’s Veterinary Drugs. Tulsa (OK): Educational Concepts, L.L.C. [updated 8/14; accessed 8/14/15]. https://www.plumbsveterinarydrugs.com/#!/monograph/2566
– Papich MG. Saunders Handbook of Veterinary Drugs: Small and Large Animal. 3rd ed. St. Louis, MS: Elsevier Saunders; 2011.

Pet Poison Control is provided free as a public service by the American College of Veterinary Pharmacists. Today we’re asking you to support us with a small donation. If you would like to dedicate your gift in honor or memory of a pet or individual, you will have that option before checkout. Your gift of any amount helps us maintain this resource and make it available to the pharmacy and veterinary communities. Thank you!

Loading...