When providing dietary instructions for a client on cyclosporine, which item should be excluded from the diet?

Grapefruit juice should be excluded from the diet of a client on cyclosporine because it can significantly interfere with the metabolism of the medication. Cyclosporine is primarily metabolized by the liver enzyme CYP3A4, and grapefruit juice contains compounds that inhibit this enzyme, leading to increased blood levels of cyclosporine. This increase can enhance the drug's effects and increase the risk of toxicity, as higher concentrations of cyclosporine can lead to adverse effects such as kidney damage and increased susceptibility to infections.

In contrast, citrus fruits generally do not have this inhibitory effect on cyclosporine metabolism. Bananas and diet sodas do not pose a known interaction with cyclosporine and can generally be included in the diet unless otherwise indicated by specific dietary restrictions or preferences.