Primary care providers can facilitate tuberculosis (TB) preventive treatment (TPT) for most individuals with TB infection (TBI). TPT is provided according to the table below.
First-line regimen
| Regimen | Duration | Dose | Frequency | Common Adverse Effects | Evaluation |
|---|
| Rifampin (4R) | 4 months | 10mg/kg (max 600 mg) | Daily | Rash, drug interactions | Monthly clinical
assessment1
ALT, bilirubin, CBC
after 1 month (or
monthly if test result
abnormal, adverse
event detected or risk
factors for
hepatotoxicity
present) |
Second-line regimen
| Regimen | Duration | Dose | Frequency | Common Adverse Effects | Evaluation |
|---|
| Isoniazid (9H) | 9 months | 5mg/kg (max 300 mg) + Pyridoxine2 25 mg | Daily | Hepatoxicity, peripheral neuropathy | Monthly clinical assessment1, Monthly ALT, bilirubin |
For alternate regimens, refer to Canadian TB Standards.
The primary goal of testing for tuberculosis infection (TBI) is to identify people who are at increased risk for development of tuberculosis (TB) disease and therefore may benefit from TB preventive treatment (TPT).
Risk factors for the development of TB disease
A TB skin test (TST) or interferon-gamma release assay (IGRA) blood test is used to diagnose TBI
What to do when TST/IGRA is positive
- Rule out TB disease by completing symptom assessment, physical exam, and chest x-ray
- If symptomatic or chest x-ray indicates TB disease
- instruct patient to isolate at home (provide masks)
- collect 3 sputum specimens at least 1 hour apart
- report immediately to public health services
- Complete and fax Positive TST/IGRA Reporting and Medications Order Form to public health services
Contraindications for TB skin test
- Past severe blistering TST reactions
- Extensive burns or eczema over testing sites
- Documented past TBI or TB disease with adequate treatment
- Current major viral infections
- Live vaccine in the past 4 weeks (Note: TST may be administered before or on the same day as live vaccine)
Common interpretation errors
Erythema vs Induration
Erythema or rash without induration occurs in 2-3% of persons tested. This does not indicate TBI.
BCG Vaccine History
A history of BCG vaccination received in infancy can be ignored as the cause of a positive TST result in all persons aged 10 years and older.
1 Monthly clinical assessment includes review of weight for dosing, adverse events and treatment compliance
2 Pyridoxine (vitamin B6) is recommended to be taken with each dose to minimize the risk of neuropathy
Source: Canadian Journal of Respiratory, Critical Care, and Sleep Medicine, Volume 6, Issue sup1 (2022). Canadian TB Standards, 8th Ed.
