Can you take doxycycline (doxy) for acne and trimethoprim or cephalexin (Keflex) for a urinary tract infection (UTI) at the same time?

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Taking Doxycycline for Acne with Trimethoprim or Cephalexin for UTI

Yes, you can take doxycycline for acne treatment while simultaneously taking either trimethoprim or cephalexin for a urinary tract infection (UTI), as there are no significant drug interactions between these medications when used concurrently.

Doxycycline for Acne Treatment

  • Doxycycline is recommended by the American Academy of Dermatology for moderate to severe inflammatory acne and should be used in combination with topical therapy such as benzoyl peroxide or retinoids 1, 2
  • Typical dosing is 100mg daily, with treatment limited to 3-4 months to minimize bacterial resistance 1, 3
  • Even subantimicrobial dosing (20mg twice daily or 40mg daily) has shown efficacy in moderate inflammatory acne 4, 2
  • Common side effects include gastrointestinal disturbances and photosensitivity 1, 2

Antibiotics for UTI Treatment

  • Cephalexin (Keflex) is an oral cephalosporin that achieves high concentrations in the urine and is effective against common UTI-causing organisms 5, 6
  • Trimethoprim is recommended as a second-line option for UTIs, particularly when first-line options aren't suitable 6, 7
  • The American Academy of Dermatology notes that trimethoprim-sulfamethoxazole use should be restricted to patients who are unable to tolerate tetracyclines or in treatment-resistant acne patients 1

Concurrent Use Considerations

  • There are no significant drug interactions between doxycycline and either trimethoprim or cephalexin that would prevent concurrent use 6
  • Both medications can be taken simultaneously, but spacing them apart by a few hours may help reduce gastrointestinal side effects 2
  • Ensure adequate fluid intake with both medications to reduce the risk of gastrointestinal irritation 1, 2

Important Precautions

  • Doxycycline should not be used as monotherapy for acne; always combine with topical therapy (benzoyl peroxide and/or retinoid) to prevent bacterial resistance 1, 2, 3
  • Doxycycline can cause photosensitivity, so sun protection is essential while taking this medication 1, 2
  • If you experience severe gastrointestinal disturbances, taking the medications with food (except dairy products for doxycycline) may help reduce these effects 2
  • Avoid taking doxycycline with antacids, iron supplements, or dairy products, as these can reduce its absorption 2

Duration of Treatment

  • Doxycycline for acne should be limited to 3-4 months to minimize bacterial resistance 1, 3
  • UTI treatment with trimethoprim or cephalexin typically requires a shorter course (usually 3-7 days depending on the severity and type of infection) 6, 7
  • After completing the antibiotic course for your UTI, continue the doxycycline as prescribed for your acne until your healthcare provider recommends discontinuation 1, 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Doxycycline for Acne Treatment

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Appropriate Candidates for Oral Tetracycline in Acne Treatment

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Subantimicrobial-dose doxycycline in the treatment of moderate facial acne.

Journal of drugs in dermatology : JDD, 2008

Research

Cephalexin in the therapy of infections of the urinary tract.

Postgraduate medical journal, 1983

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.

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