Clinical efficacy of amoxycillin/clavulanic acid and cefaclor in acute otitis media

Comparison of study designs for acute otitis media trials

BACKGROUND

A framework for evaluating the efficacy of antibiotics in development as well as those currently approved for acute otitis media (AOM) is needed.

OBJECTIVE

Review strengths and limitations of various antibiotic trial designs and their outcome measures.

METHODS

A review of 157 published trials involving 36,710 subjects for the treatment of AOM.

RESULTS

AOM trials have three designs: (1) clinical, clinical diagnosis and assessment of outcomes; (2) single tympanocentesis, microbiologic diagnosis (by middle ear fluid culture) and clinical assessment of outcomes; and (3) double tympanocentesis, microbiologic diagnosis and microbiologic outcome assessment. Identifiable strengths and limitations of each design are reviewed. Case definitions for entry of children in trials of AOM vary widely. The lack of stringent diagnostic criteria in a clinical design allows for inclusion of a significant proportion of children with a non-bacterial etiology (i.e., viral AOM or otitis media with effusion). Tympanocentesis increases diagnostic accuracy at study entry; however, the procedure is confounding because of its potentially therapeutic benefit and the procedure is not performed in a uniform manner. A second tympanocentesis allows a high sensitivity to detect microbiologic eradication, but it does not correlate with clinical outcomes in half of the cases. The timing of outcome assessment also varies widely among trials.

CONCLUSIONS

Improved clinical diagnosis criteria for AOM are needed to enhance specificity; emphasis on a bulging tympanic membrane has the best evidence base. Tympanocentesis within study designs has merits. At study entry it assures diagnostic accuracy but may alter outcomes and it is useful to document microbiologic outcomes but lacks specificity for clinical outcomes. For all designs, test of cure assessment 2-7 days after completion of therapy seems most appropriate.

Otitis media

Bacterial pathogens are isolated from middle ear fluid in up to 90% of children with acute otitis media (OM). Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis predominate. Acute OM can be classified as uncomplicated, persistent, recurrent or chronic. Patient age, symptom severity, prior treatment history and exposure through day-care attendance in children influences pathogen distribution, antimicrobial susceptibility and anticipated clinical and microbiological responses to empirical and pathogen-directed therapies. The natural history of acute OM without intervention is favourable. However, meta-analysis of clinical trials shows an improvement in symptom and middle ear effusion resolution with antimicrobials. Aminopenicillins, cephalosporins and macrolides are often selected as therapy for acute OM. The various agents have differing activity against acute OM pathogens, particularly organisms with resistance mechanisms and they differ in dosing schedule, side effects and compliance enhancing factors. Consideration should be given to pharmacokinetic and pharmacodynamic principles in antibiotic selection. Selection criteria include antibiotic activity against drug-resistant S. pneumoniae and efficacy against beta-lactamase-producing Gram-negative organisms. The necessary duration of treatment for acute OM varies according to multiple factors, including local preferences, but there is growing, compelling data to support short-course therapy. Tympanocentesis has been endorsed in various guidelines as a diagnostic and therapeutic procedure. Best-practice for management of acute OM continues to advocate antibiotic therapy with careful, accurate diagnosis and consideration of the major pathogens and their mechanisms of resistance.

Amoxycillin/clavulanic acid: a review of its efficacy in over 38,500 patients from 1979 to 1992

A review of the published literature detailing the clinical use of amoxycillin/clavulanic acid spanning the period 1979 to 1992 was undertaken to assess the clinical efficacy of the product and to determine whether any changes had occurred during this time. In the 415 publications meeting the selection criteria a total of over 38,500 patients were treated with amoxycillin/clavulanic acid. Analysis of the data confirms the efficacy of amoxycillin/clavulanic acid over a wide range of clinical indications and annual and triennial groupings of publications suggests that there has been little change in the clinical effectiveness of amoxycillin/clavulanic acid. Clinical efficacy rates (cure or improved) with amoxycillin/clavulanic acid were 88% and 92% in comparative and uncontrolled trials, respectively. Gastro-intestinal side effects are the most common adverse event but have been relatively infrequent. Amoxycillin/clavulanic acid should continue to be a useful antibiotic for upper and lower respiratory tract infections, skin structure infections, dental, head and neck infections, and selected urinary tract infections.

Update on otitis media. Part 2. Treatment

Currently the treatment of choice for OM is an oral antimicrobial agent, but selecting a specific agent should include consideration of efficacy, adverse effect profile, compliance, and cost. The use of adjunctive medications like decongestants for specific subtypes of OM has been debated in the literature, but efficacy has not been proven. As knowledge about the pathogenesis of OM is further refined, new treatment modalities for OM will be introduced. Because pharmacists are involved daily with pediatric patients who experience OM, they have an important role in making sure that patients receive appropriate therapy. A patient's profile should be checked for allergies and concurrent medications when a prescription for an antimicrobial agent is presented for a child with OM. The parents should be counseled about the administration, storage, and general product use as well as potential adverse effects, duration of use, and the need for compliance. An administration device for drug delivery like an oral syringe should be provided. Parents need advice from the pharmacist in making sure their children receive the best possible pharmaceutical care.

Recent advances in the treatment of otitis media

Otitis media (OM) continues to be a major cause of morbidity in infants and children. Antibiotics are presently the mainstay of treatment. A variety of agents including vaccinations against the most common causative organisms, prednisone, non-steroidal anti-inflammatory agents, intravenous immune globulin, antihistamines, decongestants, and topical antibiotics have been investigated. This review will address the recent developments in the treatment and prevention of OM.

A review of clinical trials regarding treatment of acute otitis media

A survey was made of the English language literature on clinical trials of therapy in acute otitis media. The articles were analysed systematically for 24 parameters related to study design. We retrieved 50 studies published between 1965 and 1989. Surprisingly, the combination of a double-blind method, clearly defined inclusion criteria, and criteria for outcome was found in only 13 studies. Most of these 13 compared different antibiotic regimens and only 4 were placebo-controlled. A recommendation based on the conclusions reached can, even in these 13 studies, hardly be obtained due to failure to show an overall difference in favour of a specific treatment regimen. Our study shows that many trials are methodologically flawed which makes it difficult to accept their results. In view of current controversy on management of acute otitis media, well conducted placebo-controlled clinical trials are still needed.