A comparative study of amoxicillin-clavulanate and amoxicillin. Treatment of otitis media with effusion

Antibiotics for otitis media with effusion in children

BACKGROUND

Otitis media with effusion (OME) is characterised by an accumulation of fluid in the middle ear behind an intact tympanic membrane, without the symptoms or signs of acute infection. Since most cases of OME will resolve spontaneously, only children with persistent middle ear effusion and associated hearing loss potentially require treatment. Previous Cochrane reviews have focused on the effectiveness of ventilation tube insertion, adenoidectomy, nasal autoinflation, antihistamines, decongestants and corticosteroids in OME. This review, focusing on the effectiveness of antibiotics in children with OME, is an update of a Cochrane review published in 2012.

OBJECTIVES

To assess the benefits and harms of oral antibiotics in children up to 18 years with OME.

SEARCH METHODS

The Cochrane ENT Information Specialist searched the ENT Trials Register; Central Register of Controlled Trials (CENTRAL 2016, Issue 3); PubMed; Ovid EMBASE; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 April 2016.

SELECTION CRITERIA

Randomised controlled trials comparing oral antibiotics with placebo, no treatment or therapy of unproven effectiveness in children with OME.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

Twenty-five trials (3663 children) were eligible for inclusion. Two trials did not report on any of the outcomes of interest, leaving 23 trials (3258 children) covering a range of antibiotics, participants, outcome measures and time points for evaluation. Overall, we assessed most studies as being at low to moderate risk of bias.We found moderate quality evidence (six trials including 484 children) that children treated with oral antibiotics are more likely to have complete resolution at two to three months post-randomisation (primary outcome) than those allocated to the control treatment (risk ratio (RR) 2.00, 95% confidence interval (CI) 1.58 to 2.53; number needed to treat to benefit (NNTB) 5). However, there is evidence (albeit of low quality; five trials, 742 children) indicating that children treated with oral antibiotics are more likely to experience diarrhoea, vomiting or skin rash (primary outcome) than those allocated to control treatment (RR 2.15, 95% CI 1.29 to 3.60; number needed to treat to harm (NNTH) 20).In respect of the secondary outcome of complete resolution at any time point, we found low to moderate quality evidence from five meta-analyses, including between two and 14 trials, of a beneficial effect of antibiotics, with a NNTB ranging from 3 to 7. Time periods ranged from 10 to 14 days to six months.In terms of other secondary outcomes, only two trials (849 children) reported on hearing levels at two to four weeks and found conflicting results. None of the trials reported data on speech, language and cognitive development or quality of life. Low quality evidence did not show that oral antibiotics were associated with a decrease in the rate of ventilation tube insertion (two trials, 121 children) or in tympanic membrane sequelae (one trial, 103 children), while low quality evidence indicated that children treated with antibiotics were less likely to have acute otitis media episodes within four to eight weeks (five trials, 1086 children; NNTB 18) and within six months post-randomisation (two trials, 199 children; NNTB 5). It should, however, be noted that the beneficial effect of oral antibiotics on acute otitis media episodes within four to eight weeks was no longer significant when we excluded studies with high risk of bias.

AUTHORS' CONCLUSIONS

This review presents evidence of both benefits and harms associated with the use of oral antibiotics to treat children up to 16 years with OME. Although evidence indicates that oral antibiotics are associated with an increased chance of complete resolution of OME at various time points, we also found evidence that these children are more likely to experience diarrhoea, vomiting or skin rash. The impact of antibiotics on short-term hearing is uncertain and low quality evidence did not show that oral antibiotics were associated with fewer ventilation tube insertions. Furthermore, we found no data on the impact of antibiotics on other important outcomes such as speech, language and cognitive development or quality of life.Even in situations where clear and relevant benefits of oral antibiotics have been demonstrated, these must always be carefully balanced against adverse effects and the emergence of bacterial resistance. This has specifically been linked to the widespread use of antibiotics for common conditions such as otitis media.

Antibiotics for otitis media with effusion in children

BACKGROUND

Otitis media with effusion (OME) is characterised by an accumulation of fluid in the middle ear behind an intact tympanic membrane, without the symptoms or signs of acute infection. In approximately one in three children with OME, however, a bacterial pathogen is identified in the middle ear fluid. In most cases, OME causes mild hearing impairment of short duration. When experienced in early life and when episodes of (bilateral) OME persist or recur, the associated hearing loss may be significant and have a negative impact on speech development and behaviour. Since most cases of OME will resolve spontaneously, only children with persistent middle ear effusion and associated hearing loss potentially require treatment. Previous Cochrane reviews have focused on the effectiveness of ventilation tube insertion, adenoidectomy, autoinflation, antihistamines, decongestants, and oral and topical intranasal steroids in OME. This review focuses on the effectiveness of antibiotics in children with OME.

OBJECTIVES

To assess the effects of antibiotics in children up to 18 years with OME.

SEARCH METHODS

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the search was 22 February 2012.

SELECTION CRITERIA

Randomised controlled trials comparing oral antibiotics with placebo, no treatment or therapy of unproven effectiveness. Our primary outcome was complete resolution of OME at two to three months. Secondary outcomes included resolution of OME at other time points, hearing, language and speech, ventilation tube insertion and adverse effects.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data using standardised data extraction forms and assessed the quality of the included studies using the Cochrane 'Risk of bias' tool. We presented dichotomous results as risk differences as well as risk ratios, with their 95% confidence intervals. If heterogeneity was greater than 75% we did not pool data.

MAIN RESULTS

We included 23 studies (3027 children) covering a range of antibiotics, participants, outcome measures and time points of evaluation. Overall, we assessed the studies as generally being at low risk of bias.Our primary outcome was complete resolution of OME at two to three months. The differences (improvement) in the proportion of children having such resolution (risk difference (RD)) in the five individual included studies ranged from 1% (RD 0.01, 95% CI -0.11 to 0.12; not significant) to 45% (RD 0.45, 95% CI 0.25 to 0.65). Results from these studies could not be pooled due to clinical and statistical heterogeneity.Pooled analysis of data for complete resolution at more than six months was possible, with an increase in resolution of 13% (RD 0.13, 95% CI 0.06 to 0.19).Pooled analysis was also possible for complete resolution at the end of treatment, with the following increases in resolution rates: 17% (RD 0.17, 95% CI 0.09 to 0.24) for treatment for 10 days to two weeks, 34% (RD 0.34, 95% CI 0.19 to 0.50) for treatment for four weeks, 32% (RD 0.32, 95% CI 0.17 to 0.47) for treatment for three months, and 14% (RD 0.14, 95% CI 0.03 to 0.24) for treatment continuously for at least six months.We were unable to find evidence of a substantial improvement in hearing as a result of the use of antibiotics for otitis media with effusion; nor did we find an effect on the rate of ventilation tube insertion. We did not identify any trials that looked at speech, language and cognitive development or quality of life. Data on the adverse effects of antibiotic treatment reported in six studies could not be pooled due to high heterogeneity. Increases in the occurrence of adverse events varied from 3% (RD 0.03, 95% CI -0.01 to 0.07; not significant) to 33% (RD 0.33, 95% CI 0.22 to 0.44) in the individual studies.

AUTHORS' CONCLUSIONS

The results of our review do not support the routine use of antibiotics for children up to 18 years with otitis media with effusion. The largest effects of antibiotics were seen in children treated continuously for four weeks and three months. Even when clear and relevant benefits of antibiotics have been demonstrated, these must be balanced against the potential adverse effects when making treatment decisions. Immediate adverse effects of antibiotics are common and the emergence of bacterial resistance has been causally linked to the widespread use of antibiotics for common conditions such as otitis media.

New formulations of amoxicillin/clavulanic acid: a pharmacokinetic and pharmacodynamic review

The pharmacokinetic properties of amoxicillin and clavulanic acid when used alone or in combination are extensively reviewed and discussed in this article. The reported data support a nonlinear absorption process for amoxicillin. Saturable transport mechanisms, limited solubility and the existence of an absorption window are possibly involved in the gastrointestinal absorption of this antibacterial, all leading to a decrease in the peak plasma concentration (Cmax)/dose ratio, a prolongation of the time to reach Cmax, and broad variability for high doses of amoxicillin. Data available in the literature also suggest a possible interaction between amoxicillin and clavulanic acid that might decrease the absolute bioavailability of clavulanic acid. In the present review the intrinsic pharmacodynamics of each drug, together with the synergism produced by the amoxicillin/clavulanic acid association, are also reviewed and analysed. Not only beta-lactamase-producing strains, but also Streptococcus pneumoniae strains, seem to be more efficiently eradicated by the association of amoxicillin and clavulanic acid, and a relevant post-antibacterial effect and post-beta-lactamase inhibitor effect are likely to operate when amoxicillin is administered together with clavulanic acid. The principles of pharmacokinetic/pharmacodynamic analysis applied to amoxicillin are reviewed, with special emphasis being placed on the results obtained from in vitro studies and animal models regarding the new pharmacokinetically enhanced formulation. Theoretical considerations concerning the efficacy of this formulation provided by the application of pharmacokinetic/pharmacodynamic analysis to the scarce pharmacokinetic data available are also included. The broad pharmacokinetic variability of both amoxicillin and clavulanic acid, particularly when administered together and at high doses of amoxicillin, is highlighted and the interest in considering this aspect to improve predictions based on pharmacokinetic/pharmacodynamic analyses for the new formulations is indicated. Methodological recommendations such as the Monte Carlo simulation are proposed in order to obtain more realistic predictions in clinical practice.

Recent Developments in the Treatment of Otitis Media with Effusion

The management of otitis media with effusion (OME) has received much attention recently as a result of, among other factors, the development of resistant bacteria and the finding of less long-term impact of middle-ear effusion (MEE) on development than previously believed. Guidelines have recently been published for the management of OME promoting more accurate diagnosis, particularly distinguishing acute otitis media from OME, and recommending the 'judicious' use of antibacterials. Today, more emphasis is being placed on prevention of disease by reducing risk factors and the development of vaccines. The identification of susceptibility genes may lead to better understanding of the pathogenesis of otitis media, which in turn may lead to the development of more innovative and satisfactory methods for prevention and treatment.

Could one of the most widely prescribed antibiotics amoxicillin/clavulanate "augmentin" be a risk factor for autism?

Autism is an ever increasing problem in the United States. Characterized by multiple deficits in the areas of communication, development, and behavior; autistic children are found in every community in this country and abroad. Recent findings point to a significant increase in autism which can not be accounted for by means such as misclassification. The state of California recently reported a 273% increase in the number of cases between 1987 and 1998. Many possible causes have been proposed which range from genetics to environment, with a combination of the two most likely. Since the introduction of clavulanate/amoxicillin in the 1980s there has been the increase in numbers of cases of autism. In this study 206 children under the age of three years with autism were screened by means of a detailed case history. A significant commonality was discerned and that being the level of chronic otitis media. These children were found to have a mean number 9.96 bouts of otitis media (with a standard error of the mean of +/-1.83). This represents a sum total for all 206 children of 2052 bouts of otitis media. These children received a mean number of 12.04 courses of antibiotics (standard error of the mean of +/-.125). The sum total number of courses of antibiotics given to all 206 children was 2480. Of those 893 courses were Augmentin. with 362 of these Augmentin courses administered under the age of one year. A proposed mechanism whereby the production of clavulanate may yield high levels of urea/ammonia in the child is presented. Further an examination of this mechanism needs to be undertaken to determine if a subset of children are at risk for neurotoxicity from the use of clavulanic acid in pharmaceutical preparations.

Studies in otitis media: Children's Hospital of Pittsburgh-University of Pittsburgh progress report--2004

OBJECTIVES/HYPOTHESIS

The present Progress Report has summarized the key otitis media clinical trials and laboratory studies conducted since 1969 by investigators at the Children's Hospital of Pittsburgh-University of Pittsburgh (Pittsburgh, PA).

STUDY DESIGN

Review.

METHODS

Included in the discussion are the following: 1) studies of the epidemiology and risk factors; 2) anatomy and pathology of the eustachian tube-middle ear from human temporal bone histopathological specimens; 3) physiology and pathophysiology of the eustachian tube-middle ear in humans and animal models; 4) pathogenesis; 5) otitis media in special populations (e.g., patients with cleft palate, Native Americans, patients with Down syndrome); 6) microbiology; 7) diagnosis; 8) outcomes of randomized clinical trials that evaluated efficacy of nonsurgical and surgical methods of treatment and prevention; 9) studies of certain complications and sequelae (e.g., effect of middle-ear effusion on hearing, early child development, and the vestibular system; chronic suppurative otitis media). Also included are relevant summary tables and 256 references.

Systemic steroid for chronic otitis media with effusion in children

OBJECTIVE

To determine the efficacy of a short course of an adrenocorticosteroid agent (prednisolone) given with amoxicillin as compared with that of amoxicillin alone for the treatment of chronic middle ear effusion (MEE). The efficacy of 2 weeks versus 4 weeks of amoxicillin with and without steroid was also assessed.

METHODS

In a double-blind, randomized trial, children who were 1 to 9 years of age and had MEE of at least 2 months' duration were assigned to 1 of 4 treatment arms: 1) steroid + amoxicillin for 14 days, then amoxicillin for 14 more days; 2) steroid + amoxicillin for 14 days, then placebo for amoxicillin for 14 more days; 3) placebo (for steroid) + amoxicillin for 14 days, then amoxicillin for 14 more days; or 4) placebo (for steroid) + amoxicillin for 14 days, then placebo for amoxicillin for 14 more days. Children were examined by otoscopy, tympanometry, and audiometry at entry and 2 and 4 weeks after entry; those without MEE at the 4-week visit returned monthly for up to 3 more visits or until recurrence of effusion. Serum immunoglobulin (Ig) G, IgM, IgA, and varicella titers were obtained at entry, and allergy skin testing was performed at the 4-week visit.

RESULTS

A total of 144 children was entered; 135 children (94%) returned for the 2-week visit, and 132 (92%) were seen for the 4-week visit. At the 2-week visit, 33.3% of children in the steroid + amoxicillin group had no MEE compared with 16.7% in the placebo + amoxicillin group (95% confidence interval for the difference in proportions: 2.4%-31.0%). At the 4-week visit, the percentage of children with no MEE in the steroid-treated group was 32.8%, whereas that in the placebo group was 20.0% (95% confidence interval for the difference in proportions in the 2 groups: -2.0%-27.7%). Comparing change in middle ear status from the 2- to the 4-week visit, there were no significant differences in recurrence of MEE or additional clearance of MEE between those who were treated with amoxicillin for 2 weeks and those who were treated for 4 weeks. By the 4-month visit, 68.4% of children who were in the steroid group and had no MEE at the 4-week visit had recurrence of MEE as did 69.2% of such children in the placebo group. A total of 126 (87.5%) children underwent allergy skin testing. Of the 122 children who had a positive reaction to histamine, 51 (41.8%) had 1 or more positive reactions to the test allergens. There was no difference in response to treatment between those with positive allergy tests and those without.

CONCLUSIONS

There was a significant difference in the proportion of children who were effusion-free immediately after 14 days of treatment with steroid and amoxicillin compared with those who were treated only with amoxicillin for 14 days. Within 2 weeks of finishing treatment, there was no longer any significant difference between the 2 groups regardless of whether amoxicillin was continued or not. Therefore, we conclude that treatment with the dose and type of steroid used in this study should not be universally recommended for treatment of chronic otitis media with effusion, and treatment with amoxicillin, if used, should not continue beyond 14 days.

Sinus tissue pharmacokinetics after oral administration of amoxicillin/clavulanic acid

OBJECTIVES

The in vitro synergy of the amoxicillin/clavulanic acid combination has not always translated in vivo into clinical superiority compared with amoxicillin alone. Specifically, conflicting reports have disputed the superiority of the combination in the treatment of both acute otitis media and acute sinusitis. One possible reason for this may have to do with inadequate target tissue pharmacokinetics. To explore this possibility in the sinuses, we undertook the present investigation.

STUDY DESIGN

A randomized, open, single-dose, sinus tissue pharmacokinetic study with oral amoxicillin/clavulanic acid.

METHODS

Twenty-three adult patients with chronic rhinosinusitis who had been selected for surgery were randomly allocated to receive a tablet of 875/125 mg amoxicillin/clavulanate 2 to 4 hours before surgery began. During the operation tissue samples were collected at specific sinonasal sites for determination of both amoxicillin and clavulanic acid concentration levels.

RESULTS

Amoxicillin displayed adequate tissue levels throughout the sinuses, high enough to cover common susceptible pathogens. However, the presence of clavulanate was detected in only half of the sinonasal tissue samples.

CONCLUSIONS

The kinetics of oral clavulanic acid apparently fails to provide a widespread anti-beta-lactamase activity capable of enhancing the activity of amoxicillin in all parts of the sinuses. Despite this, amoxicillin/clavulanic acid maintains a central role in the treatment of acute rhinosinusitis, because amoxicillin is still the most effective oral beta-lactam against Streptococcus pneumoniae, a particularly virulent and increasingly resistant upper respiratory tract pathogen. Also, as our data show, a concomitant anti-beta-lactamase activity can be expected to occur, although in an unpredictable fashion.

Efficacy of ceftibuten compared with amoxicillin for otitis media with effusion in infants and children

OBJECTIVES

This trial compared the efficacy of ceftibuten with that of amoxicillin in resolving otitis media with effusion.

METHODS

Two hundred ten children with otitis media with effusion were randomly assigned to receive either ceftibuten (9 mg/kg/day in one daily dose) or amoxicillin (40 mg/kg/day divided into 3 daily doses) for 14 days. Outcome was assessed at 2 and 4 weeks in all subjects; those without middle ear effusion at the 4-week visit were examined at 8, 12 and 16 weeks. Middle ear status was determined by pneumatic otoscopy and by an algorithm combining pneumatic otoscopy with tympanometry.

RESULTS

The percentages of subjects who were effusion-free in the ceftibuten and amoxicillin groups at 2 weeks by otoscopy were 29.8 and 27.2%, respectively (P = 0.59), and by the algorithm, 23.4 and 20.4%, respectively (P = 0.47). In children who were effusion-free at 2 weeks, recurrence of effusion by 16 weeks was noted in approximately 60% of the ceftibuten group and 67% of the amoxicillin group. No medication side effects were reported by 88% of subjects in the ceftibuten group and by 93% of subjects in the amoxicillin group. We found no significant differences between the ceftibuten and amoxicillin groups with respect to resolution of middle ear effusion, rate of recurrence or side effects.

CONCLUSIONS

Amoxicillin remains the drug of first choice for treatment of otitis media with effusion when treatment is deemed advisable, but ceftibuten may be an alternative drug in selected situations.

Current indications for tympanostomy tubes

Current indications for TT placement are (1) persistent SOM that has not responded to a 6 to 12-week course of medical treatment. This includes full and prophylactic doses of antimicrobials (and corticosteroids, as indicated); (2) recurrent AOM (at least three episodes in 6 months or four episodes in 12 months) that does not respond to, or recurs after, antimicrobial prophylaxis; (3) complications of AOM such as meningitis, facial nerve paralysis, coalescent mastoiditis, or brain abscess; and (4) complications of eustachian tube dysfunction such as tympanic membrane retraction with hearing loss, ossicular erosion, and/or retraction pocket formation. It must be emphasized that TT placement in children does not "cure" the condition that led to the surgical intervention. Rather, the TT maintains aeration of the middle ear until the child grows and his eustachian tube function normalizes. These recommendations for TT placement are to be regarded as guidelines, not as absolute requirements. They must be applied individually to each patient and his/her unique situation. Certain factors may influence timing of TT placement and lead to modification of the guidelines as they apply to each child.

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.

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.

Modern management of otitis media

In summary, infants and children who have acute otitis media should receive antimicrobial therapy. Amoxicillin is the standard of therapy for infants and children with acute otitis media, because it is safe and effective for most of the causative bacterial pathogens. Amoxicillin has also been shown to be effective for treatment of selected children with otitis media with effusion ("secretory" otitis media) and is the recommended prophylactic antimicrobial agent for prevention of frequently recurrent acute otitis media. During the past decade, however, an increasing rate of bacteria that are resistant to amoxicillin has occurred, primarily beta-lactamase-producing H. influenzae and B. catarrhalis. Because of the emergence of these bacteria, other antimicrobial agents, both old and new, have been advocated for treatment and prevention of otitis media; amoxicillin-clavulanate, cefuroxime axetil, and cefixime are the newer agents. These agents are indicated for selected infants and children; however, for most patients, amoxicillin remains a safe and relatively inexpensive effective drug. The common surgical procedures, such as myringotomy with tympanostomy tube insertion, and adenoidectomy with myringotomy with or without tympanostomy tube insertion, have now been shown to be effective for patients who have recurrent acute otitis media and chronic otitis media with effusion. The decision for or against these procedures should not only include consultation with an otolaryngologist but should also involve the parents and the child, if old enough. The risks, costs, and benefits of nonsurgical and surgical management should be discussed with all parties concerned.

Lack of efficacy of middle-ear inflation: treatment of otitis media with effusion in children

A randomized controlled trial was conducted to evaluate the efficacy of autoinflation of the middle ear in the treatment of otitis media with effusion. Forty-one children with middle ear effusion not responsive to antimicrobial therapy enrolled in the study. Of these subjects, 75 percent had effusion duration over 3 months. A system consisting of a disposable anesthesia mask attached to a flowmeter was used to teach children to perform autoinflation based on a modified Valsalva technique. Subjects were stratified according to their ability to achieve tubal opening as assessed by tympanometry and tubosonometry. Subjects were randomly assigned to either treatment or observation group and were followed weekly for 2 weeks; subjects in the treatment group attempted inflation three times each day for 2 weeks. Of the 19 subjects who were in the autoinflation group, only one (5.3 percent) was effusion-free at the two-week endpoint and of the 21 subjects in the control, only two (9.5 percent) were without middle-ear effusion. Autoinflation was ineffective for treatment of children with otitis media with effusion in our study.