Session 7 - Treatment of TB/HIV Co-Infection: Overview and Technical Update

Antiretroviral & TB Drug Interactions: Gary Maartens of the University of Cape Town discussed co-treatment of TB and HIV and focused on shared toxicity between ARV & TB therapy.  He noted that Rifampicin dramatically reduces protease inhibitor concentrations – a fact which can often be overcome by dose adjustment.  Substituting Rifabutin is not an option in developing countries.  Non-nucleoside reverse transcriptase inhibitors (NNRTIs) are less affected, but Nevirapine may need dose adjustment (no pharmacokinetic data in children).  He also discussed the worryingly low Efavirenz concentrations in children, and noted the paucity of data in this area for children.

Issues raised during Question & Answer session:

  • More research is needed on how to co-treat children younger than 3 years, or who weigh less than 10 kg. Efavirenz is only safe for children over age 3, so for children under 3, possibilities may include Kaletra, a double-dose of Kaletra, or Nevirapine or Ritonavir in places where Kaletra is not available. 
  • There are safety concerns about ethambutol use.  It is difficult to measure toxicity in children, and we may be underdosing; serum levels in children are low.  So WHO is raising the recommended dose.
  • We need better diagnostics for TB in children.  In many of the settings where ICAP works, we have microscopy but no culture.

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