A rare case of drug-induced bradycardia associated with the just low dose use of methylprednisolone in a child with COVID-19.

Methylprednisolone (MP) is usually used to reduce inflammation reaction and tissue damage, which may have a beneficial treatment effect on coronavirus disease 2019 (COVID-19). However, we present the case of a child who manifests significant bradycardia with the use of just low dose MP on the premise of the long-term use of arbidol. Arbidol can affect the activity of CYP3A4, which is also a key metabolic enzyme of MP by competitive inhibition, and which is easy to aggravate the side effects of MP. Therefore, more attention should be paid to bradycardia occurrence in the patient with COVID-19 when MP is considered in COVID-19.