What is the dosage and administration of oral liquid Bactrim (Sulfamethoxazole/Trimethoprim) DS?

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Last updated: May 19, 2025 • View editorial policy

From the Guidelines

Oral liquid Bactrim DS should be administered as 10 mL of the suspension twice daily for adults, providing the equivalent of one double-strength tablet, as this regimen is preferred for prophylactic use 1. When using oral liquid Bactrim DS, it is crucial to shake the suspension well before measuring each dose to ensure accurate medication delivery.

  • The liquid formulation contains 40 mg trimethoprim and 200 mg sulfamethoxazole per 5 mL.
  • For adults requiring the double-strength (DS) equivalent, the dose is typically 10 mL of the suspension twice daily.
  • This provides the same medication amount as one DS tablet (160 mg trimethoprim and 800 mg sulfamethoxazole).
  • The suspension can be taken with or without food, though taking it with food may reduce stomach upset.
  • It's essential to use a proper measuring device like a medication cup or oral syringe rather than household spoons to ensure accurate dosing.
  • Common side effects include nausea, vomiting, and skin rashes, and patients should maintain adequate hydration while taking this medication and complete the full prescribed course even if symptoms improve before finishing, as recommended by guidelines such as those from the USPHS/IDSA 1.

From the FDA Drug Label

The usual adult dosage in the treatment of urinary tract infections is 1 sulfamethoxazole and trimethoprim DS (double strength) tablet or 2 sulfamethoxazole and trimethoprim tablets every 12 hours for 10 to 14 days 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.

The oral liquid Bactrim DS dosage is not explicitly mentioned in the provided drug label. However, the label provides dosage information for tablets.

  • For adults, the usual dosage is 1 sulfamethoxazole and trimethoprim DS (double strength) tablet or 2 sulfamethoxazole and trimethoprim tablets every 12 hours.
  • For children, the recommended dose is 40 mg/kg sulfamethoxazole and 8 mg/kg trimethoprim per 24 hours, given in two divided doses every 12 hours. 2

From the Research

Oral Liquid Bactrim DS

  • Bactrim DS is a combination antibiotic consisting of sulfamethoxazole and trimethoprim 3, 4, 5, 6, 7
  • It is commonly used to treat various bacterial infections, including urinary tract infections (UTIs) 6
  • The effectiveness of Bactrim DS for oral step-down therapy in gram-negative bloodstream infections has been compared to fluoroquinolones and high-bioavailability β-lactams in a multicenter observational cohort study 3
  • The study found that trimethoprim-sulfamethoxazole (TMP-SMX) had similar effectiveness to fluoroquinolones, while high-bioavailability β-lactams were associated with higher recurrence rates, although this difference was not statistically significant 3
  • Another study compared the effects of fluoroquinolones and trimethoprim-sulfamethoxazole on mortality of Stenotrophomonas maltophilia infections and found that fluoroquinolones demonstrated comparable effects on mortality to trimethoprim-sulfamethoxazole 4
  • A systematic review and meta-analysis evaluated the safety profile of sulfamethoxazole-trimethoprim and identified a higher risk of rash and other adverse drug events compared to other antibiotics 5
  • The use of trimethoprim-sulfamethoxazole as a first-line treatment for acute uncomplicated UTI has been reassessed due to increasing resistance among community-acquired Escherichia coli 6
  • A systematic review of randomized trials found that fluoroquinolone, trimethoprim-sulfamethoxazole, and cephalosporin prophylaxis reduced bacteremia in patients with cancer and hematopoietic stem cell transplantation recipients 7

Dosage and Administration

  • The dosage and administration of Bactrim DS may vary depending on the specific infection being treated and the patient's medical history 6
  • It is essential to follow the recommended dosage and administration guidelines to ensure effective treatment and minimize the risk of adverse effects 5, 6

Safety and Efficacy

  • The safety and efficacy of Bactrim DS have been evaluated in various studies, including those comparing its effectiveness to other antibiotics 3, 4, 5, 6, 7
  • While Bactrim DS is generally considered effective for treating certain bacterial infections, its use may be associated with adverse effects, such as rash and other skin disorders 5

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.