The 'DS' is Bactrim DS stands for 'Double Strength'. This is to separate it from Bactrim, another commercially available drug, that contains the same active ingredients but is half the strength of Bactrim DS.


Bactrim is a combination of the following two drugs:

  • Sulfamethoxazole 400mg
  • Trimethoprim 80mg


Bactrim DS is a combination of the following two drugs:

  • Sulfamethoxazole 800mg
  • Trimethoprim 160mg


As you can see above, the milligrams content of sulfamethoxazole and trimethoprim in Bactrim DS is twice, or double, the amount that is contained in Bactrim.


The active ingredients in Bactrim as commonly referred to as TMP-SMX, TMP-SMZ, or SMX-TMP.