tacrolimus + sodium zirconium cyclosilicate

Tacrolimus + sodium zirconium cyclosilicate is a **combination of two separate drugs** sometimes administered together but not as a co-formulated pharmaceutical product. Tacrolimus is a calcineurin inhibitor immunosuppressant used to prevent organ transplant rejection by inhibiting T-cell activation via blocking calcineurin, leading to reduced interleukin-2 transcription. Sodium zirconium cyclosilicate is a non-absorbed, selective potassium binder used to treat hyperkalemia by exchanging sodium and hydrogen for potassium in the gastrointestinal tract, thereby reducing serum potassium. When co-administered, sodium zirconium cyclosilicate can reduce the bioavailability of tacrolimus, necessitating administration at least two hours apart to maintain tacrolimus efficacy.