What is the appropriate dosing of amoxicillin (amoxillin) for acute sinusitis?

From the Guidelines

For children with acute bacterial sinusitis, amoxicillin is recommended at a dose of 45 mg/kg per day in 2 divided doses for mild to moderate cases, while a higher dose of 80-90 mg/kg per day in 2 divided doses may be used in areas with high prevalence of nonsusceptible S pneumoniae or for patients with severe infection, recent antibiotic use, or other risk factors 1. The choice of antibiotic dosage depends on various factors, including the severity of the infection, the patient's age, and the presence of risk factors for resistance.

• For uncomplicated acute bacterial sinusitis in children aged 2 years or older who do not attend child care and have not been treated with an antimicrobial agent within the last 4 weeks, a standard dose of 45 mg/kg per day in 2 divided doses is recommended 1.
• In communities with a high prevalence of nonsusceptible S pneumoniae (>10%, including intermediate- and high-level resistance), treatment may be initiated at 80 to 90 mg/kg per day in 2 divided doses, with a maximum of 2 g per dose 1.
• Patients presenting with moderate to severe illness as well as those younger than 2 years, attending child care, or who have recently been treated with an antimicrobial may receive high-dose amoxicillin-clavulanate (80–90 mg/kg per day of the amoxicillin component with 6.4 mg/kg per day of clavulanate in 2 divided doses with a maximum of 2 g per dose) 1. The optimal duration of antimicrobial therapy for patients with acute bacterial sinusitis has not received systematic study, but recommendations based on clinical observations have varied widely, from 10 to 28 days of treatment 1. It is essential to note that the treatment of patients with presumed allergy to penicillin has been controversial, but recent publications indicate that the risk of a serious allergic reaction to second- and third-generation cephalosporins in patients with penicillin or amoxicillin allergy appears to be almost nil and no greater than the risk among patients without such allergy 1. In addition to the dosage and duration of antibiotic treatment, it is crucial to consider the potential side effects, such as diarrhea, nausea, and rash, and to ensure that patients complete the full course of antibiotics even if symptoms improve before completion 1. The effectiveness of amoxicillin against common sinusitis pathogens, including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis, varies geographically, and alternative antibiotics such as doxycycline or a respiratory fluoroquinolone may be necessary for patients with penicillin allergy 1.

From the FDA Drug Label

For more severe infections and infections of the respiratory tract, the dose should be one 875 mg/125 mg amoxicillin and clavulanate potassium tablet every 12 hours or one 500 mg/125 mg amoxicillin and clavulanate potassium tablet every 8 hours. Table 1: Dosing in Patients Aged 12 weeks (3 months) and Older INFECTION | DOSING REGIMEN | Every 12 hours | Every 8 hours Otitis media, sinusitis, lower respiratory tract infections, and more severe infections | 45 mg/kg/day every 12 hours | 40 mg/kg/day every 8 hours

The recommended dosing of amoxicillin for sinusitis is:

• For patients aged 12 weeks (3 months) and older: 45 mg/kg/day every 12 hours or 40 mg/kg/day every 8 hours
• For patients weighing 40 kg or more: follow adult recommendations of one 875 mg/125 mg amoxicillin and clavulanate potassium tablet every 12 hours or one 500 mg/125 mg amoxicillin and clavulanate potassium tablet every 8 hours 2

From the Research

Dosing of Amoxicillin for Sinusitis

• The optimal dosing of amoxicillin for sinusitis is not explicitly stated in the provided studies, but some studies suggest the use of high-dose amoxicillin or amoxicillin-clavulanate as a treatment option 3.
• A study comparing the sinusal penetration of amoxicillin-clavulanic acid found that a twice-daily regimen of 1 g/125 mg was equivalent to a three-times-daily regimen of 500 mg/125 mg in terms of pharmacokinetics, tissue penetration, and pharmacodynamics 4.
• Another study compared the efficacy of azithromycin with amoxicillin/clavulanic acid in the treatment of acute sinusitis and found that a 3-day course of azithromycin was as effective as a 10-day course of amoxicillin/clavulanic acid 5.
• A randomized controlled trial found that neither amoxicillin nor topical budesonide alone or in combination was effective as a treatment for acute sinusitis in the primary care setting, with a dose of 500 mg of amoxicillin three times per day for 7 days 6.
• A double-blind comparison of ciprofloxacin and amoxycillin/clavulanic acid in the treatment of chronic sinusitis found that ciprofloxacin was at least as effective as amoxycillin/clavulanic acid, with a superior safety profile and a twice-daily dosage regimen 7.

Treatment Options

• High-dose amoxicillin or amoxicillin-clavulanate may be used as a treatment option for sinusitis 3.
• Azithromycin may be an effective alternative to amoxicillin/clavulanic acid for the treatment of acute sinusitis 5.
• Ciprofloxacin may be a useful therapeutic alternative for the treatment of chronic sinusitis, with a superior safety profile and a twice-daily dosage regimen 7.

Dosage Regimens

• A twice-daily regimen of 1 g/125 mg amoxicillin-clavulanic acid may be equivalent to a three-times-daily regimen of 500 mg/125 mg in terms of pharmacokinetics, tissue penetration, and pharmacodynamics 4.
• A 3-day course of azithromycin (500 mg once daily) may be as effective as a 10-day course of amoxicillin/clavulanic acid (625 mg every 8 hours) for the treatment of acute sinusitis 5.
• A dose of 500 mg of amoxicillin three times per day for 7 days may not be effective as a treatment for acute sinusitis in the primary care setting 6.