MRCP2-2666
A 50-year-old homeless man comes in with a persistent cough, occasional coughing up of blood, and weight loss over the past two months. His chest X-ray reveals consolidation in the upper right lobe. After confirming a diagnosis of tuberculosis through microscopy, he is started on a combination of rifampicin, isoniazid, pyrazinamide, and ethambutol, along with pyridoxine supplements. However, after eight weeks, culture results indicate that the Mycobacterium tuberculosis is resistant to isoniazid. What would be the appropriate course of action for his continued treatment?