Linezolid-Associated Black Tongue: A Rare Adverse Drug Reaction

Linezolid is an effective second-line anti-tuberculosis drug. However, the use of linezolid has been associated with rare adverse drug reactions (ADRs), one of which is the linezolid-associated black hairy tongue (BHT). This reaction is characterized by a black or dark brown discoloration of the tongue, which may be accompanied by a metallic or bitter taste. In this case report, we present a 19-year-old male patient who developed linezolid-associated black tongue while receiving linezolid as part of an all-oral, longer-course treatment regime for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB). The patient's BHT was only cosmetic and resolved upon discontinuation of linezolid. This case report aims to raise awareness of this rare ADR and the importance of close monitoring and potential withdrawal of linezolid to optimize treatment outcomes.