Nondrug costs include once-monthly assessment of complete blood count and liver enzymes, two sputum specimens every 2 months, computerised tomography (CT) scan at beginning and end of therapy (otherwise chest radiography (CXR) every 3 months), physicians’ and facility fees (Canadian costs differ from our primary analysis in that facility fees for physician visits and CXR have been removed to model treatment in a nonhospital setting and facilitate comparison with the Medicare reimbursement structure; facility fees for CT scans have been retained, since CT scanners are generally operated and maintained by hospitals in Ontario, Canada, financed from hospital global budgets). Because the choice of regimen will depend more upon tolerability and goals of therapy (cure versus suppression) and because we cannot adequately assign a relative toxicity or efficacy of the regimens (greater toxicity or less effective regimens may lead to additional costs), the table should not be used to make clinical decisions. ATS: American Thoracic Society; IDSA: Infectious Diseases Society of America; BTS: British Thoracic Society. ^#: US drug costs derived according to the methods of Ballarino et al. 4 and from personal communication with the authors. ^¶: sources of nondrug costs are Medicare reimbursement rates calculated as the median of national nonfacility limiting charges from the centre for Medicare and Medicaid services (for physician fees and imaging) and mid-point costs from the 2008 Medicare Clinical Laboratory Fee Schedule (microbiology and blood tests); Medicare reimbursement rates are generally lower than those of private insurers, so the costs may be substantially higher for patients in the USA whose care is being charged to private insurance.