Skip to Content
Print Share

Bactrim Dosage

Generic name: SULFAMETHOXAZOLE 800mg, TRIMETHOPRIM 160mg
Dosage form: tablet

Medically reviewed by Drugs.com. Last updated on Jun 16, 2020.

BACTRIM is contraindicated in pediatric patients less than 2 months of age.

Urinary Tract Infections and Shigellosis in Adults and Pediatric Patients, and Acute Otitis Media in Children:

Adults: The usual adult dosage in the treatment of urinary tract infections is 1 BACTRIM DS (double strength) tablet or 2 BACTRIM tablets every 12 hours for 10 to 14 days. An identical daily dosage is used for 5 days in the treatment of shigellosis.

Children: The recommended dose for children with urinary tract infections or acute otitis media is 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, given in two divided doses every 12 hours for 10 days. An identical daily dosage is used for 5 days in the treatment of shigellosis. The following table is a guideline for the attainment of this dosage:

Children 2 months of age or older:
Weight Dose–every 12 hours
lb kg Tablets

22

10

–

44

20

1

66

30

1½

88

40

2 or 1 DS tablet

For Patients with Impaired Renal Function: When renal function is impaired, a reduced dosage should be employed using the following table:

Creatinine
Clearance (mL/min)		 Recommended Dosage Regimen

Above 30

Usual standard regimen

15–30

½ the usual regimen

Below 15

Use not recommended

Acute Exacerbations of Chronic Bronchitis in Adults:

The usual adult dosage in the treatment of acute exacerbations of chronic bronchitis is 1 BACTRIM DS (double strength) tablet or 2 BACTRIM tablets every 12 hours for 14 days.

Pneumocystis Jiroveci Pneumonia:

Treatment: Adults and Children:

The recommended dosage for treatment of patients with documented Pneumocystis jiroveci pneumonia is 75 to 100 mg/kg sulfamethoxazole and 15 to 20 mg/kg trimethoprim per 24 hours given in equally divided doses every 6 hours for 14 to 21 days.9 The following table is a guideline for the upper limit of this dosage:

Weight Dose–every 6 hours
lb kg Tablets

18

8

–

35

16

1

53

24

1½

70

32

2 or 1 DS tablet

88

40

2½

106

48

3 or 1½ DS tablets

141

64

4 or 2 DS tablets

176

80

5 or 2½ DS tablets

For the lower limit dose (75 mg/kg sulfamethoxazole and 15 mg/kg trimethoprim per 24 hours) administer 75% of the dose in the above table.

Prophylaxis:

Adults:

The recommended dosage for prophylaxis in adults is 1 BACTRIM DS (double strength) tablet daily.10

Children:

For children, the recommended dose is 750 mg/m2/day sulfamethoxazole with 150 mg/m2/day trimethoprim given orally in equally divided doses twice a day, on 3 consecutive days per week. The total daily dose should not exceed 1600 mg sulfamethoxazole and 320 mg trimethoprim.11 The following table is a guideline for the attainment of this dosage in children:

Body Surface Area Dose–every 12 hours
(m2) Tablets

0.26

–

0.53

½

1.06

1

Traveler's Diarrhea in Adults:

For the treatment of traveler's diarrhea, the usual adult dosage is 1 BACTRIM DS (double strength) tablet or 2 BACTRIM tablets every 12 hours for 5 days.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Related questions

Medical Disclaimer

Next → Professional

Drugs.com Mobile Apps

The easiest way to lookup drug information, identify pills, check interactions and set up your own personal medication records. Available for Android and iOS devices.

Explore Apps