Amoxicillin Dosing for a 20kg Child with LRTI and Asthma Exacerbation
For a 20kg child with lower respiratory tract infection (LRTI) and asthma exacerbation, the recommended dose of amoxicillin is 45 mg/kg/day in 3 divided doses (900mg total daily dose) or 90 mg/kg/day in 2 divided doses (1800mg total daily dose), depending on the severity of infection and local pneumococcal resistance patterns. 1
Dosing Recommendations Based on Weight and Infection Severity
- For mild to moderate lower respiratory tract infections, the recommended dose is 45 mg/kg/day divided into 3 doses (approximately 300mg three times daily for a 20kg child) 1
- For severe lower respiratory tract infections or in areas with high pneumococcal resistance, a higher dose of 90 mg/kg/day divided into 2 doses (approximately 900mg twice daily for a 20kg child) is warranted 1, 2
- According to FDA labeling, for lower respiratory tract infections in pediatric patients weighing less than 40kg, the recommended dose is 45 mg/kg/day in divided doses every 12 hours or 40 mg/kg/day in divided doses every 8 hours 3
Treatment Duration Considerations
- Treatment should be continued for a minimum of 7-10 days 1
- Therapy should continue for at least 48 to 72 hours beyond the time that the patient becomes asymptomatic or evidence of bacterial eradication has been obtained 3
- For infections caused by Streptococcus pyogenes, a minimum of 10 days of treatment is recommended to prevent acute rheumatic fever 3
Special Considerations for Asthma Exacerbation
- In patients with asthma exacerbations and LRTI, amoxicillin is commonly prescribed, though recent evidence suggests limited efficacy for uncomplicated chest infections 4
- A 7-day course of amoxicillin is associated with fewer repeat antibiotic prescriptions in patients with asthma and LRTI compared to shorter courses 5
- Consider that patients with asthma may have increased susceptibility to respiratory infections, which might influence treatment decisions 6
Monitoring and Follow-up
- Clinical improvement should be expected within 48-72 hours of initiating appropriate antibiotic therapy 7
- If the child's condition deteriorates or shows no improvement within 48-72 hours, further investigation should be performed 7
- Monitor for common adverse effects including gastrointestinal disturbances (diarrhea, nausea, vomiting) and potential hypersensitivity reactions 1
Important Clinical Pearls
- Administer amoxicillin at the start of a meal to minimize gastrointestinal intolerance 3
- Shake oral suspension well before using and refrigerate the reconstituted suspension (though refrigeration is preferable but not required) 3
- Any unused portion of the reconstituted suspension must be discarded after 14 days 3
- For patients with severe renal impairment (GFR <30 mL/min), dose adjustment is necessary, but this is rarely a concern in otherwise healthy children 3