Establishing Effective Antifungal Medication Dosing in Alpacas

Lisa F. Shubitz, DVM, University of Arizona, D19LA-005

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RESULTS: Antifungal medication dosing recommendations for Valley Fever in alpacas. Morris Animal Foundation-funded researchers at the University of Arizona established dosing recommendations for the antifungal medication fluconazole, a treatment for coccidioidomycosis or Valley Fever, in alpacas. Alpacas living in the southwestern United States are at risk of infection caused by the fungus Coccidioides, endemic in the soil in parts of this region. Infection is acquired by inhaling spore-laden dust. Primary infection begins as a respiratory infection but often spreads throughout the alpaca's body, causing severe disease.

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Affected alpacas are treated with the antifungal medication fluconazole. Although fluconazole is used effectively to treat coccidioidomycosis in many other species, including humans, alpacas absorb oral medications less efficiently which could lead to treatment failure.

After studying the drug by taking several blood samples over a period of time from client-owned alpacas, the team established therapeutic dosing range for fluconazole of 10-15 mg/kg/day. Since absorption is unpredictable in alpacas, the team recommends testing plasma levels after two weeks and adjusting dosages if necessary, to ensure therapeutic levels; about one-third of the study animals had unpredictably low drug absorption.

In addition to the pharmacokinetic data, the team discovered subclinical disease in three of 13 alpacas (23%) screened for enrollment in the study. This finding highlights the prevalence of Valley Fever in Arizona and the need for screening procedures to help detect early disease.

Findings from this study provided clinical guidelines for fluconazole in alpacas to guide treatment in affected animals. Data also advanced our understanding of bioavailability of fluconazole in alpacas and may help inform treatment recommendations for other systemic fungal diseases in the species.

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Thank you to the Llama Association of North America for your generous sponsorship of this study!