What is the appropriate dosage of oral amoxicillin (amoxicillin) for a 13-year-old patient?

From the Guidelines

The appropriate dosage of oral amoxicillin for a 13-year-old patient is 90 mg/kg/day, divided into two doses, with a maximum dose of 4 g/day, as recommended by the most recent and highest quality study 1. This dosage is based on the patient's weight, with the goal of achieving an effective therapeutic level while minimizing potential side effects.

• The dosage can be calculated by multiplying the patient's weight in kilograms by 90 mg/kg/day, and then dividing the result into two doses.
• For example, a 13-year-old patient weighing 50 kg would require a dose of 4500 mg/day, which can be divided into two doses of 2250 mg each.
• It is essential to note that the exact dosage and treatment duration should be determined by a healthcare provider based on the specific infection being treated, the patient's medical history, and other relevant factors.
• Amoxicillin is a commonly used antibiotic that works by preventing bacteria from building cell walls, causing them to die.
• Potential side effects may include diarrhea, stomach upset, or rash, and the medication should be taken with food to reduce stomach upset.
• The patient should also drink plenty of water while taking this antibiotic to help prevent dehydration and promote healing.
• If the patient has any allergies to penicillin or cephalosporins, amoxicillin should not be used, and alternative treatment options should be explored 1.

From the FDA Drug Label

2.2 Dosage for Adults and Pediatric Patients Aged 3 Months (12 weeks) and Older Treatment should be continued for a minimum of 48 to 72 hours beyond the time that the patient becomes asymptomatic, or evidence of bacterial eradication has been obtained It is recommended that there be at least 10 days’ treatment for any infection caused by Streptococcus pyogenesto prevent the occurrence of acute rheumatic fever. Table 1 (12 weeks) n 40 kg Recommended Dosage for Pediatric Patients Aged 3 Months and Older and Weight Less than 40 kg Ear/Nose/Throat Mild/ Moderate 500 mg every 12 hours or 250 mg every 8 hours 25 mg/kg/day in divided doses every 12 hours or 20 mg/kg/day in divided doses every 8 hours 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

For a 13-year-old patient, the dosage of oral amoxicillin is not explicitly stated in the provided text for patients over 12 weeks old and over 40 kg. However, based on the information provided for adults and pediatric patients aged 3 months and older, the dosage for a patient over 40 kg can be considered as follows:

• Mild/Moderate infections: 500 mg every 12 hours or 250 mg every 8 hours
• Severe infections: 875 mg every 12 hours or 500 mg every 8 hours 2

From the Research

Amoxicillin Dosage for a 13-Year-Old Patient

• The appropriate dosage of oral amoxicillin for a 13-year-old patient can be determined based on the patient's weight, as recommended by several studies 3, 4, 5, 6.
• According to the study by 4, high-dose amoxicillin (70-90 mg/kg/day) is recommended as first-line therapy for acute otitis media in children.
• Another study by 6 found that lower-dose amoxicillin (35-50 mg/kg/d) was noninferior to higher-dose amoxicillin (70-90 mg/kg/d) in terms of clinically indicated antibiotic re-treatment for respiratory infection within 28 days.
• The British National Formulary for Children (BNFC) guidance recommends oral antibiotic dosing according to age bands as a proxy for weight, but a study by 7 found that this approach can lead to underdosing or overdosing in some children.
• A study by 5 recommends using the child's weight to calculate the dose in mg per kg, without exceeding the maximum adult dose, to ensure accurate dosing.

Considerations for Dosage Calculation

• When calculating the dosage, it is essential to consider the child's weight and the recommended dose range per kilogram of body weight 3, 4, 5, 6.
• The study by 6 suggests that a dose of 35-50 mg/kg/d may be sufficient for some children, while others may require a higher dose of 70-90 mg/kg/d.
• It is crucial to consult reputable guidelines, such as Therapeutic Guidelines: Antibiotic, for up-to-date advice on optimal choice, route, dosage, and duration of oral penicillins in children 5.