A Canadian perspective on the American Academy of Pediatrics guidelines for acute otitis media

Abstract

In 2004, the American Academy of Pediatrics (AAP) and the American Academy of Family Physicians (AAFP) published guidelines on the management of acute otitis media (AOM) (1). These are summarized in Table 1. The guidelines contain new recommendations for both empirical and second-line antibiotic treatments; however, some of the drugs recommended are not available in Canada. What are these recommendations, and what are the options for the prescribing Canadian physician? TABLE 1 The American Academy of Pediatrics otitis media guidelines The AAP/AAFP clinical practice guideline is a comprehensive document that covers diagnosis and management, including weighing the option of observation and symptomatic treatment, pain control, prevention measures, as well as appropriate choices for antibacterial medications. We will address the recommended antibiotics and explain why these drugs are recommended, as well as provide options for drugs that are not available in Canada. The first major new recommendation in the AAP/AAFP guidelines is an increase in the empirical treatment dose of amoxicillin. Specifically, the guidelines recommend that for most children, if an antibacterial agent is to be used, then the first-line agent to be prescribed should be amoxicillin at 80 mg/kg/day to 90 mg/kg/day. This was based on a Centers for Disease Control and Prevention (CDC) recommendation that the empirical treatment dose of amoxicillin should be increased from 40 mg/kg/day to 45 mg/kg/day, to 80 mg/kg/day to 90 mg/kg/day, owing to the rising prevalence of drug-resistant Streptococcus pneumoniae (DRSP) (2). In general, one cannot just increase the dose of a drug to overcome resistance; however, the mechanism of penicillin resistance is such that increasing the dose of amoxicillin results in serum levels that can overcome the resistance. This is based on in vitro data, not clinical trials. Penicillin susceptibility is geographically dependent, both in the United States and Canada. Thus, the CDC guidelines acknowledge that patients at very low risk for DRSP may still be treated with a regular dose of amoxicillin. This refers to patients older than two years of age, those without antibiotic exposure in the past three months and those with no daycare attendance. Moreover, since the publication of these guidelines, new data have emerged from the United States showing a change in the relative frequency of the different isolates causing AOM as a result of conjugated pneumococcal vaccine use. A significant drop (greater than 10%) in the rates of DRSP in certain communities was reported, especially in areas in which the vaccine has had universal recommendations (3); an overall decrease in the frequency of S pneumoniae isolates relative to Haemophilus influenzae (4) causing AOM was also reported. The Canadian Paediatric Society is currently revising the Canadian guidelines for first-line antibiotic treatment of AOM. In the interim, it would seem prudent to weigh all the risk factors (eg, age, daycare attendance, previous antibiotic exposure and geographical rate of drug resistance), as well as vaccination status (5) in the decision to choose high- versus standard-dose amoxicillin. It is important to remember that high-dose amoxicillin could cause diarrhea as an adverse effect. In patients with severe illness (moderate to severe ear pain and fever of 39°C or higher) and in those who fail to respond to initial management within 48 h to 72 h, the guidelines recommend the use of high-dose amoxicillin-clavulanate in two divided doses, in a 14:1 formulation (90 mg/amoxicillin component to a 6.4 mg/clavulin component). The addition of clavulanate is effective against the beta-lactamase-producing strains of H influenzae or Moraxella catarrhalis, which are thought to be the pathogens responsible for disease in those who fail initial amoxicillin treatment. Because this formulation is not available in Canada, one may prescribe the 7:1 Clavulin (GlaxoSmithKline Inc, Canada) product containing 45 mg/kg/day of the amoxicillin component and an additional amoxicillin dose of 45 mg/kg/day for a combined total of 90 mg/kg/day of amoxicillin. Clavulin-200 and -400 suspensions (7:1) are given every 12 h (6). If this treatment fails, the guidelines recommend a three-day course of parenteral ceftriaxone, owing to its superior efficacy against S pneumoniae compared with the oral antibiotics.