The recommended sulfamethoxazole/trimethoprim dosage for most uses is 800/160 mg every 12 hours. The length of treatment, which ranges from 5 to 14 days, will vary depending on the type of infection being treated. This 800/160 mg dose can be taken as one double-strength tablet, two regular-strength tablets, or 4 teaspoonfuls of the oral suspension (liquid).
Sulfamethoxazole/Trimethoprim Dosage: An Introduction
The dose of sulfamethoxazole/trimethoprim (Bactrim®, Bactrim® DS, Septra®, Septra® DS, Sulfatrim®) that your healthcare provider recommends will vary, depending on a number of factors, including:
- The type of infection and bacteria
- Your height and weight (for some uses)
- Other medical conditions you may have
- Other medications you may currently be taking.
As is always the case, do not adjust your dosage unless your healthcare provider specifically instructs you to do so.
Dosing for Adults
The recommended sulfamethoxazole/trimethoprim dosing for adults with normal kidney function is as follows:
- Pneumocystis carinii pneumonia treatment -- dosage based on weight, taken every 6 hours for 14 to 21 days
- Pneumocystis carinii pneumonia prevention -- sulfamethoxazole/trimethoprim 800/160 mg once daily
- Urinary tract infection (UTI) treatment -- sulfamethoxazole/trimethoprim 800/160 mg every 12 hours for 10 to 14 days
- Shigellosis or traveler's diarrhea treatment -- sulfamethoxazole/trimethoprim 800/160 mg every 12 hours for 5 days
- Acute worsening of chronic bronchitis treatment -- sulfamethoxazole/trimethoprim 800/160 every 12 hours for 14 days.
The dose of sulfamethoxazole/trimethoprim 800/160 mg can be taken as one DS ("double-strength") tablet, two regular-strength tablets, or 4 teaspoonfuls (20 mL) of the oral suspension (liquid).
Lower sulfamethoxazole/trimethoprim dosages may be recommended for people with kidney disease.