From the FDA Drug Label
Lower Respiratory Tract Mild/ Moderate or Severe 875 mg every 12 hours or 500 mg every 8 hours 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours The recommended dose of amoxicillin for Lower Respiratory Tract Infections (LRTI) is:
- 875 mg every 12 hours or 500 mg every 8 hours for adults
- 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours for pediatric patients aged 3 months and older and weight less than 40 kg 1 1
From the Research
For lower respiratory tract infections (LRTIs), the recommended dose of amoxicillin for adults is typically 500 mg three times daily or 875 mg twice daily for 5-7 days, as supported by the most recent and highest quality study available 2.
Key Considerations
- The dose may be increased to 875 mg three times daily for more severe infections.
- Children's dosing is weight-based, usually 45-90 mg/kg/day divided into two or three doses.
- For community-acquired pneumonia or bronchitis, a 5-day course is often sufficient, while more complicated infections may require 7-10 days of treatment.
- Amoxicillin works by inhibiting bacterial cell wall synthesis, making it effective against many common respiratory pathogens like Streptococcus pneumoniae and Haemophilus influenzae.
Important Notes
- In areas with high prevalence of beta-lactamase producing organisms, amoxicillin-clavulanate may be preferred.
- Take amoxicillin with or without food, though taking with food may reduce gastrointestinal side effects.
- Complete the full course of antibiotics even if symptoms improve before finishing the prescription to prevent antibiotic resistance and ensure complete eradication of the infection.
Comparison with Other Antibiotics
- Azithromycin, a macrolide antibiotic, has been shown to be effective in treating acute LRTIs, particularly in patients with acute bronchitis of a suspected bacterial cause 2.
- However, the evidence is unclear regarding the superiority of azithromycin over amoxycillin or amoxyclav in treating acute LRTIs.