From the Guidelines
Doxycycline 100mg twice daily for 7 days is not recommended for treating acute bronchitis, but it may be effective for treating sinusitis, particularly when caused by common respiratory pathogens, as suggested by the most recent and highest quality study 1.
Key Points to Consider
- Acute bronchitis is usually caused by a viral pathogen, and antibiotics are rarely effective for acute cough and are not indicated for acute cough from the common cold, acute bronchitis, asthma, mild exacerbations of chronic bronchitis related to smoking, or environmental irritants 1.
- Acute bacterial rhinosinusitis (ABRS) is considered to be a secondary infection resulting from obstruction of the sinus ostia that leads to impaired mucosal clearance as a result of a viral upper respiratory tract infection (URI) 1.
- Doxycycline or a respiratory fluoroquinolone may be used as an alternative in patients with ABRS, but amoxicillin–clavulanate is the preferred agent 1.
- Clinicians should reserve antibiotic treatment for acute rhinosinusitis for patients with persistent symptoms for more than 10 days, onset of severe symptoms or signs of high fever (>39 °C) and purulent nasal discharge or facial pain lasting for at least 3 consecutive days, or onset of worsening symptoms following a typical viral illness that lasted 5 days that was initially improving (double sickening) 1.
Important Considerations for Treatment
- Take doxycycline with a full glass of water, either with food or on an empty stomach if it causes stomach upset.
- Remain upright for at least 30 minutes after taking it to prevent esophageal irritation.
- Complete the entire 7-day course even if symptoms improve earlier to prevent antibiotic resistance and ensure complete eradication of the infection.
- If symptoms worsen or don't improve after 2-3 days, contact your healthcare provider as you may need a different antibiotic or additional treatment.
From the Research
Effectiveness of Doxycycline for Acute Bronchitis and Sinusitis
- The effectiveness of doxycycline for treating acute bronchitis and sinusitis can be inferred from several studies 2, 3, 4, 5, 6.
- A study from 1975 compared doxycycline and ampicillin in the treatment of acute sinusitis, and found that doxycycline had significantly superior results, with 90% of patients responding to doxycycline compared to 35% for ampicillin 2.
- Another study from 2025 discussed the treatment of acute rhinosinusitis, and mentioned doxycycline as an appropriate antibiotic for patients with a beta-lactam allergy 3.
- A meta-analysis from 2009 found that short-course antibiotic treatment (up to 7 days) had similar effectiveness to longer-course treatment for patients with acute uncomplicated bacterial sinusitis 4.
- A review from 2004 examined the issues surrounding short-course antibiotic therapy for acute sinusitis, and found that accumulating evidence suggests that short-course antibiotic therapy may have equivalent or superior efficacy compared to traditional longer therapies 5.
- A study from 2002 discussed the management of acute bacterial sinusitis in adults, and recommended a 10-day course of amoxicillin for patients who fail to improve with symptomatic treatment, with second-line antibiotics initiated if improvement is not seen within 72 to 96 hours 6.
Dosage and Duration of Doxycycline Treatment
- The study from 1975 used a dosage of 200 mg on the first day, followed by 100 mg daily for a total of 7 days 2.
- The meta-analysis from 2009 found that short-course treatment (up to 7 days) had similar effectiveness to longer-course treatment for patients with acute uncomplicated bacterial sinusitis 4.
- The review from 2004 suggested that a 5-day course of antibiotic therapy may be sufficient for uncomplicated acute maxillary sinusitis in adults 5.