After 24 hours of supportive care (intravenous fluids, antiemetics), Miss Kitty is no longer vomiting; she is well-hydrated and eating small amounts. Now for the challenge-how to treat a cat with both renal disease and hyperthyroidism. We know that treating the hyperthyroidism will decrease the glomerular filtration rate (GFR) and potentially worsen the azotemia. However, if left untreated, hyperthyroidism may result in gastrointestinal side effects, hypertension, cardiac disease, and worsening renal function. The best approach in these cases is conservative management of the thyroid condition with a low starting dose of oral medication such as methimazole. Our hope is that a more gradual decline in the GFR will lessen the impact on her kidneys.
Now that you have sent Miss Kitty home with client instructions to feed a renal diet and administer methimazole at a dosage of 1.25 mg orally twice daily, what is the next step in her management?