Long-Term Evaluation of Canine Perianal Fistula Disease Treated With
Exclusive Fish and Potato Diet and Surgical Excision


“The records of 33 dogs that had perianal fistula disease treated with en blocsurgical excision and bilateral anal saculectomy, and that were perioperatively administered an exclusive white fish and potato diet, were reviewed to determine outcome. By 1 year after surgery, 87.9% of the dogs had complete or near-complete resolution of visible fistula disease, while only 20.7% continued to have mild intermittent clinical signs. Fecal incontinence was not reported in any dog. Overall, complications were considerably less in both severity and frequency when compared with previous reports.”

Journal of the American Animal Hospital Association November/December 2008 vol. 44 no. 6 302-307

The above study took thirty-three dogs with perianal fistula disease and used a combination of medical, dietary, and surgical treatments and evaluated these dogs after one year of surgery. The results showed that eighty-seven percent of the treated dogs had complete or near complete resolution of all symptoms. The medical therapy included preoperatively one to one hundred eighty days of cephalexin, metronidazole and sulfasalazine. These drugs were continued for thirty to sixty days postoperatively. The dogs were fed Eukenuba FP exclusively for the entire preoperative medication and continued for the duration of the study The surgery included anal sacculectomy and en bloc resection of all diseased tissue.

The diet may have two benefits. First of all, the diet may be helpful in some cases in avoiding potential allergens which may cause colitis. Secondly, the omega acids may decrease thomboxanes in the chronic phase of inflammation.

Serum pharmacokinetics of clindamycin hydrochloride in normal dogs
when administered at two dosage regimens


“The aim of this cross-over study was to compare clindamycin pharmacokinetics in the serum of clinically normal dogs when administered orally at two dosage regimens (5.5 mg/kg, twice daily, and 11 mg/kg, once daily), separated by a 1 week wash-out period. Serum samples were obtained from six clinically normal laboratory beagles before, 3, 6, 9 and 12 h after the first and fifth dose of clindamycin at 5.5 mg/kg, twice daily, and before, 3, 6, 9, 12, 18 and 24 h after the first and third dose at 11 mg/kg, once daily. Serum clindamycin concentrations were determined by reverse-phase liquid chromatography coupled with mass spectrometry. Results were analysed using Student’s paired t-test, at a 5% level of significance. Values of pharmacokinetic parameters that differed significantly between the two dosage regimens included the following: maximal concentration and area under the concentration–time curve were higher at 11 mg/ kg, once daily, than at 5.5 mg/kg, twice daily; and, more importantly, the ratio of AUC0–24 to the minimal inhibitory concentration (MIC) value of 0.5 μg/mL for a 24 h period (AUC0–24/MIC) was higher when clindamycin was administered at 11 than at 5.5 mg/kg, at least during the first day of drug administration. Therefore, a better pharmacokinetic profile may be expected when clindamycin is administered at 11 mg/ kg, once daily, for the treatment of canine pyoderma caused by Staphylococcus pseudintermedius.”

Veterinary Dermatology (2011) Volume: 22, Issue: 5, Pages: 429-435

The above study indicated that eleven mg/kg every twenty four hours was at least as good or possibly
better than five and a half mg/kg every twelve hours from a pharmacokinetic profile. There are clinical
studies that indicate that pyoderma responds at least as well with the once a day treatment. Most
studies indicate that Staphylococcus pseudintermedius has about a seventy-nine percent sensitivity toclindamycin. Our clinical impression and experience with clindamycin suggests the following; multiple
uses of the drug in the same patient will often result in resistance developing. Vomiting or gastro-intestinal signs are rarely a problem as it is in cephalexin use. The use of clindamycin has not been associated with increased development of methicillin-resistant S. pseudintermedius (MRSP). A small number of our MRSP cases are sensitive to clindamycin as indicated by culture results. We have seen cases where the lower dosage of clindamycin does not work as well as the higher dosage.

Case Report Issue #1 2012

Richmond Location

Patient Signalment: “Ranger” – a 5 year old male, 38 kg, intact German shepherd used for breeding was
referred with a 2 month history of left sided perianal fistula that was unresponsive to therapy.

Case Report: Highest incidence of perianal fistulae are observed in middle-aged German shepherds. The
cause for the development of these fistulae is unclear, but anatomic factors and a dysregulated immune
response have been suspected. Food allergy has been incriminated in some cases. Thus, underlying food
hypersensitivity should be identified and treated in these dogs.

Treatment Plan:

  • Combination therapy was opted in order to achieve complete cure.
  • Dietary change to exclusive Eukanuba FP Skin and coat response.
  • Bilateral anal sacculectomy and perianal fistula En block resection by Dr Hutchinson at Boundary Bay Specialists.
  • Antimicrobial therapy: Combination therapy with Metronidazole, Cefalexin and Sulfasalazine (see
    article attached).

Reference: Long term evaluation of canine perianal fistula disease treated with exclusive fish and potato diet and surgical excision. JAAHA 44:302-307 (2008).

Follow-up and Outcome:

  • Day 12 post surgery – patient was doing well with no discharge or discomfort at the surgery site.
    Small fistula formed at surgery site that was self healing when kept on 3 drug antimicrobial therapy.
  • Histopathological diagnosis – Perianal fistula with associated vasculitis and anorectal polyp,
    secondary to inflammation.
  • 8 month follow-up since treatment – patient is doing well and has had no recurrence on the fish
    and potato diet.