A 54-year-old woman presents to the clinic with one week of worsening fatigue, poor appetite, nausea, and dark urine. For the last 2 days, her husband has noted a yellow discoloration of her eyes. Two months ago, she had a positive tuberculin skin test during a routine work screening. A chest x-ray was normal, and she was diagnosed with latent tuberculosis infection (LTBI). She was started on isoniazid monotherapy 6 weeks prior to this visit. Her only other medical problem is hypertension, which is well-controlled. She drinks one to two glasses of wine on weekends and denies using any herbal remedies or dietary supplements. She occasionally takes acetaminophen for headaches, but has not exceeded 2 grams in any 24-hour period. Her initial laboratory studies are as follows:

WBC: 8,500/mm³ (4,500-11,000)

Hemoglobin: 13.0 g/dL (12.0-16.0)

Platelets: 280,000/mm³ (150,000-450,000)

AST: 950 U/L (10-40)

ALT: 1250 U/L (7-56)

Alkaline phosphatase: 150 U/L (44-147)

Total Bilirubin: 6.5 mg/dL (0.1-1.2)

Direct Bilirubin: 4.8 mg/dL (0.0-0.3)

INR: 1.3 (0.8-1.1)

Albumin: 3.8 g/dL (3.5-5.0)