Signal of safety due to adverse drug reactions induced by tacrolimus with or without azithromycin.

INTRODUCTION

We identified two reports of drug levels increased and acute kidney injury caused by the drug-drug interaction between azithromycin (AZM) and tacrolimus (TAC). However, it is unclear whether the combination of these two drugs causes additive or synergistic adverse drug reactions. Therefore, we evaluated the disproportionality in reporting drug level increased and acute kidney injury for these two drugs are used alone and in combination with each other.

METHOD: Data from the US Food and Drug Administration's Adverse Event Reporting System from 1974 to Q3/2021 were used. Reports based on exposure to macrolide antibiotic alone, TAC alone, and each macrolide antibiotic + TAC were extracted. Proportional reporting ratios (PRRs) and 95% confidence intervals (CIs) were calculated, and a lower limit of the 95% CI (Lower95CI) value of 2.0 or higher was interpreted as a signal of safety.

RESULTS

Lower95CIs for macrolide antibiotic alone and TAC showed no potential signals of safety, including drug level increase, acute kidney injury, and control event. The PRRs and 95% CI for drug levels increased were 3.27 (2.69-3.97) for AZM + TAC, and 10.81 (9.59-12.17) for clarithromycin (CAM) + TAC. For CAM + TAC, the PRR and 95% CI were 8.42 (7.51-9.44) in acute kidney injury. However, AZM + TAC was not associated with a signal of safety in acute kidney injury.

CONCLUSIONS

This suggests that AZM + TAC has a low risk of causing acute kidney injury but may cause increased drug levels.