Inadequate therapeutic response to a recommended antituberculosis fixed-dose combination regimen in an overweight patient with Mycobacterium bovis infection.

Objective: To report a case of an overweight man with lymph node tuberculosis due to Mycobacterium bovis, a part of the Mycobacterium tuberculosis complex, treated with fixed-dose combination (FDC) chemotherapy.

Case Report: Following guidelines, according to the patient's weight (92 kg), we prescribed the maximum recommended doses of isoniazid-rifampin-pyrazinamide FDC. It led initially to underdosing, with a poor clinical outcome, justifying increased doses and a complex regimen using separate drugs (isoniazid 600 mg, rifampin 1200 mg, and levofloxacin 1000 mg) to achieve therapeutic drug concentrations and clinical response.