African Journal of Medical Case Reports

ISSN 2756-3316

African Journal of Medical Case Reports ISSN 2756-3316 Vol. 14 (3), pp. 001-011, March, 2026. Available online at www.internationalscholarsjournals.org © International Scholars Journals

Full Length Research Paper

Impact of Diarrhoea and Calcium Channel Blockers on Tacrolimus Toxicity: A Systematic Review

Sandrine Leroy1,2* Sonia Fargue3,4 Albert Bensman2 Georges Deschênes5 Evelyne Jacqz-Aigrain6 and Tim Ulinski2

1Centre for Statistics in Medicine, University of Oxford, Oxford, United-Kingdom.
2Department of Pediatric Nephrology, Armand-Trousseau Hospital, AP-HP and University Paris VI, Paris, France.
3Department of Biology, University College London, London, United-Kingdom.
4Department of Pediatric Nephrology - Reference Centre for Rare Renal Diseases, Femme Mère Enfant Hospital, University of Lyon, Lyon, France.
5Department of Pediatric Nephrology, Robert-Debré Hospital, AP-HP, Paris, France.
6Department of Pediatric Pharmacology - Pharmacogenetics and Clinical Investigation Center - CIC9202, Robert-Debré Hospital, AP-HP, Paris, France.

Accepted 24 November, 2025

Tacrolimus is widely used for solid-organ transplant immunosuppression. Adverse events can happen in recipients with diarrhoea or calcium channel blockers (CCBs) co-administration. We undertook a systematic review on adverse events in recipients treated with Tacrolimus for whom a raised tacrolimus trough level (≥10 ng/ml) was reported, in a situation of diarrhoea or CCB co-administration. From 312 identified studies, 16 were included, representing 65 patients. Sixty-one (94%) patients were suffering from diarrhoea, 3 (5%) received concomitant CCBs, and one (2%) presented with both; 46 (71%) were adults, 45 (69%) were kidney transplant recipients. Only 9 (14%) suffered from clinical symptoms: nephrotoxicity was reported in 9%, and required dialysis in 2%, neurotoxicity in 7%, multi-organ failure in 4%, and transient liver dysfunction in 2%. One patient was found to carry polymorphisms on CYP450 and P-glycoprotein, both involved in the tacrolimus metabolism and influenced by diarrhoea and CCB administration. Although, the risk of adverse events related to raised tacrolimus through blood level in situations of diarrhea or CCB administration is well-known and can be severe, published data is still scarce. The determination of the exact frequency of such events and the risk factors involved, such as pharmacogenetic background, would require observational cohort studies.

Key words: Calcium channel blocker, cytochrome P450, diarrhoea, P-glycoprotein, transplantation, systematic review, tacrolimus.