The hidden pharmacokinetic challenge: diarrhea's influence on cyclosporine therapy: a case series.

Background: Cyclosporine is used as an immunosuppressive drug to improve graft survival rates in the field of organ transplantation. Therapeutic drug monitoring [TDM] of cyclosporine in transplant patients is crucial for optimizing drug dosage and minimizing the risks. Diarrhea is a common gastrointestinal condition, resulting in pharmacokinetic, malabsorption, and clinical consequences for people who rely on cyclosporine medication. Case presentations: The case series discusses three pediatric patients who underwent therapeutic drug monitoring of cyclosporine to guide their treatment. The first two cases involved post-renal transplant patients with glomerulonephritis, while the third case involved a patient with tubulointerstitial kidney disease. TDM was employed to guide dose adjustments. The first patient initially received 15 mg/kg but showed high trough concentration. The dosage was gradually reduced, while diarrhea was managed. The second and third patients exhibited a similar trend which also necessitated dose adjustments. Clinical discussion: Diarrhea was identified as a factor impacting cyclosporine levels. This case series evaluated the impact of diarrhea on cyclosporine therapeutic levels in three pediatric renal transplant patients. TDM in cyclosporine therapy is significant due to its narrow therapeutic index and variable pharmacokinetics. Elevated trough concentrations led to a gradual dose reduction to achieve the target levels. Conclusion: This case series highlights the importance of TDM-guided dosing of cyclosporine, particularly in patients with diarrhea, to maintain target trough concentrations.