Do not use VISTIDE if you • Are hypersensitive (allergic) to cidofovir or any of the other ingredients of VISTIDE. • Have pre-existing kidney disease. • Or if you cannot take the medicine probenecid because of a serious allergy to probenecid or other sulfa-containing medications (e. g. sulfamethoxazole). • VISTIDE must not be administered by intraocular injection.