Linezolid administration to lactating Wistar rats affects the health of their offspring

Lactational exposure to antibacterial medications may affect the normal development of newborns during this crucial stage and later in adult life. Linezolid (LNZ) is an oxazolidinone antibacterial drug that is effective against drug-resistant Gram-positive bacteria and multidrug-resistant Mycobacterium tuberculosis. Although it is relatively toxic, there is insufficient data about LNZ use during lactation. This study aimed to elucidate the impact of linezolid administration during lactation on Wistar rats' offspring. Eighteen lactating Wistar female rats were separated into three groups (n = 6): control, therapeutic, and low dose groups. The therapeutic dose group received 61.66 mg/kg of LNZ (equivalent to the human dose), while the low dose group received 15.41 mg/kg of LNZ (1/4 of the human therapeutic dose) by gavage twice daily. All lactating dams and their offspring died four days after receiving a therapeutic dose. In the low dose group, LNZ significantly reduced the body weight of lactating females and their pups. The liver tissue of the pups showed a considerable increase in malondialdehyde levels, along with a decrease in the catalase, glutathione, and superoxide dismutase activities accompanied by moderate histological alterations like congestion, and infiltration, and DNA fragmentation as indicated by comet assay. Microscopic examination of renal tissue revealed glomeruli deterioration, cellular infiltration, and intratubular protein deposits. In conclusion, this study highlights the potential risks linezolid may pose to infants during postpartum. Therefore, there is a need for preweaning monitoring and caution should be taken during breastfeeding.