A 45-year-old woman presents with a 9-month history of symmetrical pain and stiffness in the small joints of her hands and wrists, worse in the morning and lasting more than 1 hour. Examination reveals synovitis of the metacarpophalangeal and proximal interphalangeal joints. Rheumatoid factor and anti-CCP antibodies are positive. According to Australian guidelines, which is the preferred initial disease-modifying anti-rheumatic drug (DMARD)?