What is the Azithromycin dosage for a 38kg patient with acute pharyngitis?

From the Guidelines

For a 38kg patient with acute pharyngitis, the recommended dosage of azithromycin is 12mg/kg once daily for 5 days, which equals approximately 456mg daily (rounded to 500mg for practical dosing). This dosage is based on the guidelines provided by the Infectious Diseases Society of America, as stated in the 2012 update 1 and further supported by the 2013 update 1. The medication should be taken at least 1 hour before or 2 hours after meals for optimal absorption. Azithromycin is effective against Group A Streptococcus, the most common bacterial cause of pharyngitis, as well as atypical pathogens. It works by inhibiting bacterial protein synthesis and has a long half-life allowing for once-daily dosing. Patients should complete the full course even if symptoms improve before finishing the medication, as emphasized in the clinical practice guideline for the diagnosis and management of group a streptococcal pharyngitis 1. Some key points to consider when prescribing azithromycin include:

• The importance of accurate diagnosis to prevent inappropriate administration of antimicrobials to large numbers of patients with nonstreptococcal pharyngitis 1
• The potential for resistance to azithromycin, which varies geographically and temporally 1
• The need to complete the full course of treatment to ensure eradication of the organism from the pharynx 1

From the FDA Drug Label

The recommended dose of azithromycin for children with pharyngitis/tonsillitis is 12 mg/kg once daily for 5 days. PEDIATRIC DOSAGE GUIDELINES FOR PHARYNGITIS/TONSILLITIS (Age 2 years and above, see PRECAUTIONS—Pediatric Use.) Based on Body Weight PHARYNGITIS/TONSILLITIS: (5-Day Regimen) Dosing Calculated on 12 mg/kg/day for 5 days. Weight200 mg/5 mLTotal mL per Treatment CourseTotal mg per Treatment Course KgLbs.Day 1–5 408812.5 mL (2½ tsp) 62.5 mL2500 mg

For a 38kg patient, the dosage can be calculated as follows:

• 12 mg/kg/day * 38 kg = 456 mg/day Since the patient weighs 38kg, which is close to the 40kg weight listed in the table, we can estimate the dosage to be around 12.5 mL (2½ tsp) per day, with a total treatment course of 62.5 mL and 2500 mg for 5 days 2.

From the Research

Azithromycin Dosage for Acute Pharyngitis

• The recommended dosage of azithromycin for a patient with acute pharyngitis is 60 mg/kg, given either as 12 mg/kg once daily for 5 days or 20 mg/kg once daily for 3 days 3, 4.
• For a 38kg patient, the total dose would be 60 mg/kg x 38 kg = 2280 mg, which can be administered as 12 mg/kg x 38 kg = 456 mg once daily for 5 days or 20 mg/kg x 38 kg = 760 mg once daily for 3 days.
• It is essential to note that the dosage and duration of treatment may vary depending on the specific clinical guidelines and the patient's response to treatment 5, 6.
• Azithromycin has been compared to penicillin V in the treatment of acute group A streptococcal pharyngitis, with similar clinical efficacy but lower bacteriologic eradication rates 7.

Considerations for Treatment

• The treatment of acute pharyngitis should be guided by clinical decision rules, rapid antigen testing, and throat culture, if necessary 5, 6.
• Antibiotics, including azithromycin, should only be prescribed for patients with confirmed group A beta-hemolytic streptococcal infection 5, 6.
• The choice of antibiotic and dosage should be based on the patient's age, weight, and medical history, as well as the severity of the infection 3, 4.