Study to compare the effectiveness of an antimicrobial vs. probiotic for management of hepatic encephalopathy in dogs

Utility of a probiotic for management of hepatic encephalopathy in dogs

Joe Bartges, DVM, PhD, DACVIM, DACVN (UGA Internal Medicine faculty) Cara Martin, DVM (UGA Internal Medicine resident)
Tracy Hill, DVM, DACVIM, PhD, DECVIM-CA (University of Minnesota, Internal Medicine) Genna Atiee, DVM, DACVIM (Texas A & M, Interventional Radiology)

If interested please contact our Clinical Trials Coordinator Lisa Reno via email ( or phone at 706-296-7818.

Study description:
Hepatic encephalopathy (HE) occurs in dogs with congenital liver disease and is manifested by lethargy, hypersalivation, abnormal mentation and more severe signs including seizures, coma, and possibly death. Medical management is often utilized until dogs can reach 7-8 months of age to allow the vena cava and shunt vessel to stabilize in size, prior to surgical intervention. Currently there is no standardized medical management for HE. Medical management typically includes moderate protein-restricted diets, non-absorbable disaccharides such as lactulose, antimicrobials, and antiepileptics with occasional reports of probiotics and synbiotics, with the goal of reducing serum ammonia levels.

This pilot study will evaluate the efficacy of metronidazole (antimicrobial) and Visbiome® (probiotic) for management of clinical signs, serum ammonia levels and dysbiosis index in dogs with HE.

Inclusion criteria:

  • Dogs of any breed, sex, or weight between 6 months and 6 years of age
  • HE secondary to congenital portosystemic shunts diagnosed via ultrasound or CT
  • Clinical signs consistent with grade 2 HE based on modified West Haven scale

Exclusion criteria:

  • Historical attenuation of a portosystemic shunt
  • Dog is receiving other antimicrobials (amoxicillin, amoxicillin-clavulanate, etc.)
  • Dogs receiving lactulose (will allow 1 week washout prior to baseline evaluation)
  • Other co-morbid diseases

Dogs will be screened prior to initiation of the study and will receive a baseline physical exam and lab work consisting of complete blood count, biochemical analysis, urinalysis, and ammonia levels. Dogs accepted into the study will be randomized to receive either metronidazole or Visbiome for the 2-week study duration. Dogs will be fed a diet formulated for management of liver disease for at least 1 week and continued through the 2 week study. In addition, levetiracetam will be started at least 1 week prior to baseline evaluation and continued through the 2 week study. Clinical signs will be monitored by clients with the use of a client survey and activity monitors worn by the participating dogs. On Day 0 and 14 dogs will return for a recheck to have blood drawn for ammonia levels and voided feces will be collected for assessment of dysbiosis index.

The costs of the office exams, required laboratory analysis of samples, treatment with metronidazole or Visbiome®, and the activity collars will be paid for by the study. Owners will be responsible for the costs of the liver support diet and levetiracetam.

Duration of study:
This study is currently OPEN.

Potential benefits to veterinary medicine:
Results from this study may provide veterinarians and pet parents with another treatment option for medical management of dogs with hepatic encephalopathy, without having the undesirable side effects, disruption of intestinal microbiome, or antibiotic resistance that may come with antibiotic use.

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