Is doxycycline (antibiotic) effective for treating bacterial sinusitis?

From the Guidelines

Doxycycline is effective for treating bacterial sinusitis and is considered a second-line antibiotic option. The typical adult dosage is 100 mg twice daily for 5-10 days, with 7 days being the most common duration, as recommended by the American College of Physicians and the Centers for Disease Control and Prevention 1. Doxycycline works by inhibiting bacterial protein synthesis, and it's particularly useful for patients who are allergic to penicillins or who have not responded to first-line treatments like amoxicillin or amoxicillin-clavulanate.

Key Considerations

• Doxycycline provides good coverage against many common sinusitis-causing bacteria, including some resistant strains 1.
• When taking doxycycline, patients should take it with a full glass of water and remain upright for at least 30 minutes afterward to prevent esophageal irritation.
• The medication should be taken with food to minimize stomach upset.
• Patients should avoid dairy products, antacids, and supplements containing calcium, magnesium, iron, or zinc within 2 hours of taking doxycycline as these can reduce its absorption.
• Common side effects include photosensitivity (increased sun sensitivity), so sun protection is advised during treatment 1.
• Doxycycline is not recommended for pregnant women, nursing mothers, or children under 8 years due to potential effects on bone development and tooth discoloration.

Clinical Guidelines

• The 2012 IDSA clinical practice guidelines recommend empirical antibiotics as soon as a clinical diagnosis of ABRS is established on the basis of clinical criteria 1.
• Amoxicillin–clavulanate is the preferred agent, and doxycycline or a respiratory fluoroquinolone may be used as an alternative in patients with ABRS.
• The American Academy of Otolaryngology–Head and Neck Surgery emphasizes watchful waiting (without antibiotic therapy) as initial management for all patients with uncomplicated ABRS, regardless of severity 1.

From the FDA Drug Label

Doxycycline is indicated for the treatment of the following infections: ... Respiratory tract infections caused by Mycoplasma pneumoniae. ... Respiratory tract infections caused by Haemophilus influenzae. Respiratory tract and urinary tract infections caused by Klebsiella species. ... Upper respiratory infections caused by Streptococcus pneumoniae 2

• Doxycycline is indicated for the treatment of respiratory tract infections caused by certain microorganisms, including Streptococcus pneumoniae, which can cause bacterial sinusitis.
• The FDA drug label does not explicitly state that doxycycline is effective for treating bacterial sinusitis, but it does indicate that doxycycline can be used to treat upper respiratory infections caused by Streptococcus pneumoniae, which is a common cause of bacterial sinusitis.
• However, culture and susceptibility testing are recommended to ensure that the bacteria causing the infection are susceptible to doxycycline. The FDA drug label does not answer the question.

From the Research

Effectiveness of Doxycycline for Bacterial Sinusitis

• The effectiveness of doxycycline for treating bacterial sinusitis is a topic of interest, with various studies providing insights into its efficacy 3, 4.
• A study published in 1997 found that doxycycline did not significantly add to the effectiveness of decongestive nose drops and steam inhalation in treating acute sinusitis-like complaints in general practice adults 4.
• However, another study published in 2025 suggests that doxycycline can be an appropriate antibiotic for patients with a beta-lactam allergy, indicating its potential use in treating bacterial sinusitis 3.

Comparison with Other Antibiotics

• Studies have compared the efficacy of different antibiotics, including amoxicillin/clavulanate, gatifloxacin, and doxycycline, in treating acute bacterial sinusitis 3, 5, 6.
• A study published in 2002 found that gatifloxacin had comparable clinical cure rates to amoxicillin/clavulanate in patients with acute bacterial sinusitis 5.
• Another study published in 2018 found that high-dose amoxicillin/clavulanate was more effective than standard-dose amoxicillin/clavulanate in treating acute bacterial sinusitis, but did not include doxycycline in the comparison 6.

Treatment Guidelines and Recommendations

• The American Family Physician recommends considering antibiotics, including doxycycline, for patients with severe symptoms or significant worsening of symptoms after 3 to 5 days 3.
• The choice of antibiotic should be based on the patient's medical history, including any allergies or previous antibiotic use, and the suspected causative pathogen 3, 7.
• Supportive care, including saline irrigation, nasal steroids or antihistamines, and decongestants, may also help reduce the severity of symptoms 3.