Is Bactrim (Trimethoprim/Sulfamethoxazole) effective for treating sinusitis?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Article Review Status
Submitted
Under Review
Approved

Last updated: March 28, 2025 • View editorial policy

From the Guidelines

Bactrim (Trimethoprim/Sulfamethoxazole) is an effective treatment option for sinusitis, particularly for patients with severe symptoms or those who are allergic to penicillins, and should be considered as an alternative to first-line antibiotics such as amoxicillin or doxycycline 1, 2.

Treatment Approach

When considering Bactrim for sinusitis treatment, it's essential to note that:

  • The typical adult dosage for acute sinusitis is Bactrim DS (double strength) taken as one tablet (800mg sulfamethoxazole/160mg trimethoprim) twice daily for 10-14 days.
  • Bactrim works by inhibiting bacterial synthesis of folic acid, which bacteria need to survive and multiply.
  • This antibiotic is particularly useful for patients who are allergic to penicillins or when first-line antibiotics have failed.

Key Considerations

Some key points to consider when treating sinusitis with Bactrim include:

  • Symptomatic treatment or reassurance is the preferred initial approach for patients with mild or moderate symptoms 1.
  • Patients with severe or persistent moderate symptoms and specific findings of bacterial rhinosinusitis should be treated with antibiotics, with narrow-spectrum agents such as amoxicillin, doxycycline, and trimethoprim-sulfamethoxazole being reasonable first-line agents 2.
  • Side effects of Bactrim may include rash, nausea, diarrhea, and sun sensitivity, and patients should be advised to drink plenty of fluids to prevent kidney complications and to contact their healthcare provider if they develop severe side effects.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Professional Medical Disclaimer

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.