A nurse is reinforcing teaching with a client who is taking oral prednisone for long-term management of chronic asthma. Which of the following information should the nurse include in the teaching?

The correct answer is C: "You should take a calcium supplement while taking this medication." Prednisone can lead to decreased bone density and increase the risk of osteoporosis. Calcium supplementation helps counteract this side effect. Option A is incorrect as rinsing the mouth is important to prevent oral thrush, but not directly related to prednisone. Option B is incorrect as prednisone should be taken with food to minimize stomach upset. Option D is incorrect as weight gain is more common with prednisone due to its effects on metabolism.