Soloxine is given for hypothyroidism. It replaces the thyroid gland hormone regulating metabolism and energy. Soloxine is not recommended with the following: dogs with Addison's Disease, thyrotoxicosis; it may interact with theophyline, warfarin, barbituarates, digoxin and phenytoin. If your dog is taking supplements with iron or calcium, don't given them within 4 hours after taking soloxine. Soloxine should be given on an empty stomach. Make sure your dog drinks enough water and stay hydrated.