Event Details

PHO Grand Rounds: Examining the evidence on short-course treatment regimens for latent tuberculosis infection – is it time to stop using isoniazid?

Treatment of latent tuberculosis infection (LTBI) is an important strategy for the prevention of tuberculosis (TB) in low-incidence countries such as Canada. Isoniazid (INH) has been the standard therapy – given daily for nine months in Canada, the United States and other high income countries. INH can cause serious side effects including liver toxicity, which can result in liver failure. In many settings, less than half of those who should take this treatment actually complete it. In the past decade, several large scale trials were completed, indicating that three months of once weekly isoniazid and rifapentine, or four months of daily rifampin, are as effective as nine months of INH to prevent active TB. These two regimens have significantly lower rates of liver toxicity and significantly better completion rates. Now is the time to start using a shorter rifamycin-based regimen and set INH aside. This session will provide participants with an overview of the emerging evidence on short-course treatment regimens for LTBI and highlight key considerations for their use.

By the end of this session, participants will be able to:

  1. Explain three key limitations of nine months of daily isoniazid - the current standard of care for the treatment of LTBI.
  2. Discuss the evidence from recent randomized trials on alternative short-course LTBI treatment regimens.
  3. Summarize the clinical indications and contraindications of the two short-course LTBI treatment regimens.


Presenter: Dr. Dick Menzies

Dr. Dick Menzies received his medical training at McGill University in Montreal and specialty training in internal medicine at the Medical College of Pennsylvania in the United States. Upon returning from Lesotho, Africa, he received further training in respiratory medicine and a Master’s degree in Epidemiology and Biostatistics at McGill University. 

Dr. Menzies has a long history of involvement in TB care and research, including the development of a TB research programme of clinical and epidemiologic studies linked with a large multi-disciplinary clinical service at the Montreal Chest Institute and the Public Health Unit of Montreal. He has developed and led international collaborative groups in nosocomial transmission of TB and treatment of latent TB, multidrug-resistant TB and INH-resistant TB. 
He has also been a consultant to national TB programs in the Dominican Republic, Guyana and Ecuador and was on sabbatical at the World Health Organization (WHO) in 2014-15 where he helped develop the Global Action Framework for TB research. He is editor of the Canadian TB Standards and has worked with WHO, American Thoracic Society and the Centers for Disease Control and Prevention, in addition to other agencies to develop guidelines for treatment of active and latent TB. 


The opinions expressed by speakers and moderators do not necessarily reflect the official policies or views of Public Health Ontario, nor does the mention of trade names, commercial practices, or organizations imply endorsement by Public Health Ontario.


Public Health Ontario Grand Rounds are a self-approved group learning activity (Section 1) as defined by the Maintenance of Certification Program of the Royal College of Physicians and Surgeons of Canada (RCPSC). In order to receive written documentation for Continuing Medical Education (CME) credits, please check “Yes” beside the question “Do you require CME credits?” on the registration form.

College of Family Physicians of Canada (CFPC) Affiliate Members may count RCPSC credits toward their Mainpro+ credit requirements. All other CFPC members may claim up to 50 Certified credits per cycle for participation in RCPSC MOC Section 1 accredited activities.

PHO Grand Rounds are also approved by the Council of Professional Experience for professional development hours (PDHs) for members of the Canadian Institute of Public Health Inspectors (CIPHI).

For more information or for a record of registration for other Continuing Education purposes, please contact events@oahpp.ca


Public Health Ontario is committed to complying with the Accessibility for Ontarians with Disabilities Act (AODA). If you require accommodations to participate in this event, please contact 647-260-7100 or events@oahpp.ca.

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Updated 13 March 2019