المحتويات
Cfz, Mfxh, Bdq, Mfx, Dlm, Lfx
Some TB drugs may cause QT prolongation and predispose to torsades de pointes, arrhythmias, and sudden death.
ECG should be performed before starting TB treatment then monitored throughout the course of treatment in patients taking these drugs.
Possible other causes include other QT prolonging drugs (Appendix 19), hypothyroidism and genetic causes such as long QT syndrome.
Mild or moderate QT prolongation (QTcF > 470 in women and > 450 ms in men and ≤ 500 ms) is common. Severe QT prolongation (QTcF > 500 ms or increase > 60 ms from baseline) is relatively rare.
- In all cases:
- Measure serum electrolytes and correct electrolyte disorders if necessary.
- Measure thyroid stimulating hormone (TSH) and, if necessary, treat hypothyroidism.
- For mild and moderate QT prolongation: monitor ECG at least weekly.
- For severe QT prolongation: stop QT prolonging drugs, hospitalise, perform continuous ECG monitoring until QT returns to normal. Once the patient is stable (normal QTcF and no electrolyte disorders), critical QT prolonging TB drugs can be reintroduced:
- Patient on Bdq: consider resuming while suspending all other QT prolonging drugs.
- Patient on Mfx: use Lfx instead.
- Patient on Cfz or Dlm: consider stopping if alternatives are available.
- Patient on QT prolonging non-TB drug: consider stopping it.