Bedaquiline and Delamanid in Children With XDR Tuberculosis: What is prolonged QTc?

Bedaquiline and delamanid used to treat extensively drug-resistant tuberculosis are known to cause prolonged QTc. Two children with extensively drug-resistant tuberculosis were put on bedaquiline and delamanid and had prolonged QTc on the Bazett formula but normal QTc by the Fridericia formula. Both had no adverse effects. Correct formula for monitoring QTc should be used thereby preventing unnecessary withholding of medicines.