# Acneiform Eruptions Possibly Triggered by Clarithromycin During Sirolimus Treatment

## TL;DR

A case report shows that acne-like skin eruptions may occur when sirolimus is combined with clarithromycin due to drug interactions.

## Contribution

This case highlights a possible drug-drug interaction between sirolimus and clarithromycin causing acneiform eruptions.

## Key findings

- Acneiform eruption occurred after clarithromycin administration during sirolimus treatment.
- The eruption resolved after stopping sirolimus and returned upon resuming it.
- The interaction may be due to elevated sirolimus levels from CYP3A inhibition by clarithromycin.

## Abstract

Acneiform eruption is the recognized dermatological side effect of sirolimus, an inhibitor of the mammalian target of rapamycin, although the pathophysiological mechanisms and dose dependency of this side effect remain unclear. This case report describes a case of a 40-year-old Japanese woman treated with systemic sirolimus who developed acneiform eruptions following the administration of clarithromycin. The acneiform eruption resolved after discontinuation of sirolimus and relapsed with the resumption. Since sirolimus and clarithromycin have a potential drug-drug interaction mediated by cytochrome P450 3A (CYP3A), this case suggests that the acneiform eruption developed in association with elevated blood levels of sirolimus. We conclude that clinicians should be aware of the possibility of developing acneiform eruption during sirolimus treatment, especially when administered with medications that inhibit CYP3A.