Aloha! You're speaking to Dr. Michael SalkinYou've described a type III hypersensitivity reaction in Ozil which can occur secondary to an abnormal response to an envenomation, environmental allergen such as pollens, molds, dust, and dust mites, drugs, ectoparasiticides, food, vaccinations, and even changes in the temperature and humidity. The standard of care is to provide antiallergenic corticosteroids such as prednisone. Antihistamines such as that with which he was injected and the Zantac are helpful in preventing such a reaction but less so when treating the reaction. Antibiotics are rarely indicated. The gastrointestinal protectant and mild antacid Antepsin (sucralfate) is helpful in comforting Ozil after his vomiting bouts.Because swelling persists it would be prudent to ask for oral prednisone to be given at this time at an immunosuppressive dose (2.2mg/kg/day) until you see a definite improvement and then taper the dose down quickly to 2.2mg/kg/day every other day until he normalizes. All the other drugs can be discontinued.Please respond with further questions or concerns if you wish.