A client who has recently undergone a kidney transplant is prescribed cyclosporine. Which action should the nurse prioritize to prevent potential toxicity?

Monitor the client's BUN and creatinine levels regularly.

Advise the client to consume grapefruit juice to enhance the medication's effectiveness.

Instruct the client to take cyclosporine with food to reduce gastrointestinal irritation.

Encourage increased fluid intake to dilute the medication in the bloodstream.