A porcine model for fixed drug eruptions in humans: The case of antipyrine in the Yucatan micropig

To date, there is no acceptable animal model to investigate fixed drug eruptions (FDEs) in humans. We briefly report here observations suggesting that the Yucatan micropig may be a useful animal model for that purpose. During an investigation of antipyrine absorption and disposition, we observed the development of FDEs after intravenous administration of a 1 g dose. Our observations were consistent with those reported in several investigations of humans taking a single dose of antipyrine. To confirm these results, a naïve micropig was challenged. A male uncastrated Yucatan micropig (27.2 kg) was given a 1 g dose of antipyrine intravenously. After 30 days, this pig was rechallenged with the same intravenous dose of antipyrine (1 g). Blood samples were obtained to examine immunological endpoints. During the initial challenge, a fluid plaque (ca. 1-1.5 cm) appeared on the left hip of the pig ca. 6 h after dosing. After the rechallenge, inflamed pink patches were observed at the same sites where the blisters formed initially; however, no blisters re-formed. Changes of neutrophil, lymphocyte and eosinophil levels from baseline were noted 8 h after challenge. The micropig did not seem otherwise affected by the FDEs. These observations suggest that the Yucatan micropig, or swine in general, may be a useful animal model for detecting drugs that may cause FDEs in humans.