Final answer:
The nurse should prioritize educating the client about avoiding large crowds and sick people and checking their heart rate before taking cyclosporine.
Step-by-step explanation:
When providing discharge instructions to a client who has undergone a heart transplant and is prescribed cyclosporine (Sandimmune), the nurse should prioritize educating the client about the importance of avoiding large crowds and people who are sick. This is because cyclosporine suppresses the immune system, which can make the client more susceptible to infections. Additionally, it is crucial for the nurse to educate the client about the need to check their heart rate before taking the medication, as cyclosporine can cause changes in heart rhythm.