SUSPECTED DRUG ERUPTION IN 7 DOGS DURING ADMINISTRATION OF FLUCYTOSINE

7 of 8 dogs receiving combination drug therapy consisting of flucytosi ne together with amphotericin B and/or a triazole for cryptococcosis o r aspergillosis developed cutaneous or mucocutaneous eruptions during the course of treatment. Lesions resolved in all cases following disco ntinuation of flucytosine despite continued administration of other an tifungals, suggesting the eruption was referable primarily to the fluc ytosine component of therapy. Lesions developed 13 to 41 days (median 20 days) after commencing flucytosine (105 to 188 mg/kg/day divided an d given every 8 h; median dose rate 150 mg/kg/day). The cumulative dos e of flucytosine given prior to the first signs of the drug eruption r anged from 1.7 to 6.8 g/kg (median 2.3 g/kg). The eruptions consisted of depigmentation, followed by ulceration, exudation and crust formati on. The scrotum was affected in all 4 male dogs, the nasal plane in 6 of 7 cases, while the lips, vulva, external ear canal and integument w ere involved in a smaller number of cases. There was considerable vari ation in the severity of lesions, with changes being most marked when flucytosine was continued for several days after lesions first appeare d. Some dogs experienced malaise and inappetence in association with t he suspected drug eruption. Healing took a variable period, typically in excess of 2 weeks after discontinuing flucytosine, with up to 2 mon ths being required for coral resolution of the lesions. All lesions re solved eventually without scarring or permanent loss of pigment.