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Bactrim Dosage

Generic name: sulfamethoxazole 800mg, Trimethoprim 160mg
Dosage form: tablet

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Medically reviewed on January 29, 2018.

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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.11 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.12

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.13 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.

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