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Combination of
IsoniazidAnti-tuberculosis medication
Clinical data
Routes of
By mouth[1]
ATC code

Isoniazid/pyridoxine/sulfamethoxazole/trimethoprim (INH/B6/CTX) is a fixed-dose combination medication for the prevention of opportunistic infections in HIV/AIDS.[1] It combines isoniazid, pyridoxine, sulfamethoxazole, and trimethoprim.[1] Specifically it is used to prevent tuberculosis, toxoplasmosis, pneumonia, malaria, and isosporiasis.[2] It is taken by mouth.[1]

Side effects may include trouble concentrating, numbness, vomiting, and rash.[2] Serious side effects may include liver problems.[2] Caution may be required in people with G6PD deficiency.[2] While it has not been well studied, use in pregnancy appears to be okay.[2]

It is on the World Health Organization's List of Essential Medicines.[1] While benefits include being able to take less pills, it is unclear if this version changes peoples adherence to treatment.[2] Other studies, however, have found fixed-dose combinations to be useful for this purpose.[2]


  1. ^ a b c d e World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
  2. ^ a b c d e f g "Isoniazid + pyridoxine + sulfamethoxazole + trimethoprim (New formulation) -- Adults". World Health Organization (WHO). Archived from the original on July 30, 2015. Retrieved 13 December 2017.