Mefenoxam pharmacokinetics after initial oral administration in dogs with pythiosis: a pilot study

The University of Florida College of Veterinary Medicine is currently recruiting dogs diagnosed with cutaneous and/or gastrointestinal pythiosis.

Enrollment Status: Currently Enrolling

Inclusion criteria: Dogs eligible for the study must be greater than 18kg and have been diagnosed with pythiosis either by culture with PCR, histopathology with PCR, and/or ELISA. They must have a Complete Blood Count, Chemistry Panel, and Urinalysis completed prior to enrollment. Any lesions consistent with pythiosis must be documented either by abdominal ultrasound (for GI) or body mapping (for cutaneous), which can be done prior to or at referral to UF; these costs will be covered by the client.

Exclusion criteria: Interested study patients must not be on any medications, as the study will be documenting blood levels after the first dose of mefenoxam is given.

Treatment: This study is a small-scale trial lasting a total of 28 days and involves 24 hours of hospitalization and 3 additional veterinary visits. Enrolled pets will have the first standard dose of mefenoxam administered in hospital. Continued treatment with mefenoxam will be performed by owners at home every 24 hours as part of the ongoing medical management for pythiosis.

Pets will be fasted for a period of 8 hours (overnight) prior to each visit. During hospitalization an IV catheter will be placed to facilitate blood sampling. One blood sample of 5ml (~1/3 tablespoon) will be drawn prior to administration of the first dose of mefenoxam, then additional samples will be drawn at 15 minutes, 30 minutes, 60 minutes, 90 minutes, 2 hours, 4 hours, 6 hours, 10 hours, and 24 hours after the first dose. Samples will be acquired from the IV catheter, unless there is difficulty obtaining a sample, in which case blood will be drawn by routine venipuncture from another vessel. After the first 24 hours your pet will be discharged on standard medications for the treatment of pythiosis including mefenoxam, terbinafine, minocycline, and prednisone. Additional visits will occur 7, 14, and 28 days later for single blood samples to monitor mefenoxam levels. These additional blood samples will need to be drawn 1-2 hours after your pet’s daily dose of mefenoxam.

Cost: The study will cover the cost of the first month of mefenoxam treatment and overnight hospitalization to obtain blood samples after the first dose. Prior to mefenoxam treatment, no other costs will be covered by the study. Costs not covered include, initial tests to diagnose pythiosis (abdominal ultrasound, biopsy, complete blood count, chemistry, urinalysis, histopathology, pythium culture, ELISA (Auburn)). Additional standard of care medications for pythiosis (prednisone/prednisolone, minocycline, and terbinafine) are not funded by this study and will be the financial responsibility of the owner.

Contacts: You can contact our Small Animal Hospital at (352) 392-2235, or complete the Study Interest Form to see if your dog qualifies.

Background: In Florida and the Southeastern United States dogs are frequently diagnosed with pythiosis, an oomycete or fungus-like disease that often has a poor prognosis. Mefenoxam is an agricultural fungicide, frequently prescribed as first line medical therapy along with other antifungals, antibiotics, and steroids. The purpose of this study is to evaluate the action of oral mefenoxam in dogs diagnosed with pythiosis. It is hypothesized that mefenoxam will significantly improve the clinical signs in dogs with oomycosis in a short period of time. Information gained from this study will help validate use of mefenoxam as part of our treatment protocol for pythiosis.


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