The patients include one with accessory pathway-mediated tachycardia considered to be exacerbated by the study medication, one with acute cholecystitis in a known case of gallstones, one case of hepatic fibrosis in a patient with fatty liver disease, and one case of increased liver enzymes, alanine aminotransferase (ALT) and aspartate aminotransferase (AST), greater than 5x the upper limit in a patient with hepatitis C combined with heavy alcohol intake. The gene discussed is GPT; the disease is hepatitis C virus infection.