Back to basics: finding an optimal cerumenolytic (earwax solvent).

An in vitro study was conducted to assess the effectiveness of the commonly used aqueous and organic cerumenolytic (earwax solvent). Three agents were included in the study: olive oil, sodium bicarbonate and urea-hydrogen peroxide complex 5% in glycerol. Distilled water was used as a control. The disintegration of preformed wax plug was noted at specific intervals. The test tube containing distilled water as a control was found to be most effective and fastest in completely disintegrating the wax. This was closely followed by sodium bicarbonate. In contrast, the organic products, namely urea-hydrogen peroxide complex 5% in glycerol showed very little cerumenolytic effect. Olive oil, the most commonly used solution, was ineffective in disintegrating the wax plug even after 24 hours. The study shows aqueous cerumenolytics are more effective than organic agents.

Ear drops for the removal of ear wax.

BACKGROUND: Problems attributed to the accumulation of wax (cerumen) are one of the most common reasons for people to present to their general practitioners with ear trouble (Sharp 1990). Treatment for this condition often involves use of a wax softening agent (cerumenolytic) in order to disperse the cerumen and reduce the need for syringing, or to facilitate syringing should it prove necessary, but there is no consensus on the effectiveness of the wide variety of cerumenolytics in use. OBJECTIVES: To assess the effectiveness of ear drops (cerumenolytics) for the removal of symptomatic ear wax. SEARCH STRATEGY: We searched the Cochrane ENT Group Register, the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, 2003), and MEDLINE and EMBASE up to March 2003. Reference lists of all trials were also manually searched. SELECTION CRITERIA: We identified all randomised controlled trials (with or without blinding) in which a cerumenolytic was evaluated in comparison with either no treatment, a placebo, or other cerumenolytics in participants with hard or impacted ear wax, and in which the proportion of participants with sufficient clearance of the external canal to make further mechanical clearance unnecessary (primary outcome measure) was stated or calculable. The full text articles of all the retrieved trials of possible relevance were reviewed by the two reviewers and the inclusion criteria applied independently. Any differences in opinion about which studies to include in the review were resolved by discussion. DATA COLLECTION AND ANALYSIS: Trials were graded for methodological quality using the Cochrane approach. Data extraction was performed in a standardised manner by one reviewer and rechecked by the other reviewer, and where necessary investigators were contacted to obtain missing information. Meta-analysis was neither possible nor considered appropriate because of the heterogeneity of the treatments, treatment amounts and durations, trial procedures, and scoring systems. A narrative overview of the results is therefore presented. MAIN RESULTS: Eight trials satisfied the inclusion criteria, the majority of which were of poor quality. In all, 587 participants received one of nine different cerumenolytics. One trial compared active treatments with no treatment, two trials compared active treatments with water or a saline 'placebo', and all eight trials placed two or more active treatments in head-to-head comparisons. Seven trials included syringing as a secondary treatment where necessary.Overall, results were inconclusive. One trial found a significant difference between one of three active agents (Cerumol) in comparison to no treatment, but no statistically significant difference was found between these three agents (sodium bicarbonate ear drops; Cerumol; sterile water). In two trials no statistical difference was found between the effectiveness of either sodium bicarbonate ear drops, Cerumol, Cerumenex or Colace versus a sterile water or saline 'placebo'. Three trials (from the same source) found statistically significant differences in favour of the same active agent (Exterol) in comparison to glycerol and Cerumol. Three trials found no statistically significant difference between two or more cerumenolytics (Otocerol versus Cerumol; Audax versus Earex; sodium bicarbonate ear drops versus Cerumol). Two trials comparing the same two cerumenolytics (Cerumenex versus Colace) also failed to show any significant benefit of one over the other. No serious adverse effects were reported from any of the interventions. REVIEWER'S CONCLUSIONS: Trials to date have been heterogeneous and of poor quality, making it difficult to offer any definitive recommendations on the effectiveness of cerumenolytics for the removal of symptomatic ear wax. Future trials should be of high methodological quality, have large sample sizes, and compare both oil-based and water-based solvents with placebo and/or no treatment.

Practice tip. Which cerumenolytic?

AIM: To test the in vitro dispersion of ear wax by four commonly used cerumenolytics. METHOD: Equal parts of the same piece of ear wax were covered with 10 mL of each preparation and observed for up to 30 days. RESULTS: Sodium bicarbonate and Waxsol dispersed wax within 2 hours, Cerumol was much slower and olive oil had no effect. CONCLUSIONS: The cheapest and most effective cerumenolytic is a solution of sodium bicarbonate.

An in vitro study to determine efficacy of different wax-dispersing agents.

An in vitro study was performed to compare the relative efficacy of a number of aqueous- and organic-based wax-dispersing preparations. Water, which was originally intended to be a control, surprisingly proved to be the most effective, whilst olive oil appeared to be almost totally ineffective as a wax dispersant. In view of the relatively high cost of commercially available preparations, these results have significant clinical potential.

A comparison of the efficacy of two ear drop preparations ('Audax' and 'Earex') in the softening and removal of impacted ear wax.

Thirty-six patients with symptoms of impacted ear wax were recruited to an open, randomized, parallel group study of 'Audax' ear drops and 'Earex' ear drops. Patients had had their symptoms for several weeks and they were assessed on entry for the degree of impaction in each ear. After using the drops, morning and evening for 4 days, they were assessed on the fifth day for degree of impaction, ease of syringing, side-effects or discomfort, and the investigator's and patient's own global impression of efficacy of the ear drops. A trend was seen showing less impaction post-treatment in the 'Audax' group than in the 'Earex' group although the difference did not reach statistical significance. A significant difference was seen in favour of 'Audax' for the frequency and ease of syringing (p < 0.005). No patients in the 'Audax' group reported any side-effect or discomfort although 1 patient using 'Earex' reported slight irritation whilst another found the smell unacceptable. The results of the investigators' and patients' own global impression of efficacy were significantly in favour of 'Audax' ear drops (p < 0.01).

A single-blind, randomized study to compare the efficacy of two ear drop preparations ('Audax' and 'Cerumol') in the softening of ear wax.

A parallel group, single-blind, randomized study was carried out in a general practice to compare the effectiveness and tolerability of two ear drop preparations ('Audax' and 'Cerumol') in the softening of ear wax in 50 adult patients with impacted or hardened ear wax. Assessments were made on entry of the amount, colour and consistency of the ear wax, symptoms, and objective hearing. Patients were then allocated at random to receive one or other preparation and instructed to use the drops, morning and evening, for 4 days after which they were reassessed. Details were recorded of any side-effects or discomfort caused by the study medication and both physician and patients were asked to give their overall opinion of treatment efficacy. Both treatments were shown to be effective in the softening of ear wax and were well tolerated, there being no significant difference between the two groups in these parameters. However, patients who had abnormal hearing before treatment had a significantly greater improvement in objective hearing after treatment with 'Audax' ear drops compared to those patients treated with 'Cerumol' ear drops. There were no between-treatment differences in either either the physician's or patient's overall assessments of effectiveness.

The mechanism of ceruminolysis.

In a previous study comparing the efficacy of a selection of commonly used ceruminolytics, the authors noted that aqueous-based preparations, and in particular solutions of sodium bicarbonate, were more effective in disintegrating cerumen than most organic-based preparations. In that study, the authors also observed that not only had the wax truly disintegrated following exposure to the aqueous-based preparations, but also that a marked degree of swelling of the wax spheres had occurred with these preparations. In this paper the mechanism of ceruminolysis was investigated by means of a number of commonly available histological techniques. Our findings show that desquamated sheets of corneocytes are the major constituent of cerumen plugs and provide the structural framework of the wax bolus. Ceruminolytics work by hydrating the keratin cells of these sheets of desquamated stratum corneum and subsequently inducing keratolysis, with disintegration of the wax.

A multicentric clinical trial comparing Otocerol with Cerumol as cerumenolytics.

Fifteen general practitioners conducted a randomized, double-blind comparative trial of two cerumenolytics, namely, Otocerol and Cerumol. A total of 106 patients were entered into the study (fifty-three in each group). Otocerol was shown to be marginally better than Cerumol in all parameters evaluated.