Problems attributed to the accumulation of wax (cerumen) are among the most common reasons for people to present to their general practitioners with ear trouble. Treatment for this condition often involves use of a wax softening agent (cerumenolytic) to disperse the cerumen, reduce the need for, or facilitate syringing, but there is no consensus on the effectiveness of the variety of cerumenolytics in use.
To assess the effectiveness of ear drops (cerumenolytics) for the removal of symptomatic ear wax.
We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2008 issue 2); MEDLINE; EMBASE; CINAHL; ISI Proceedings; Cambridge Scientific Abstracts; mRCT and additional sources for published and unpublished trials. The date of the most recent search was April 2008.
We identified all randomised controlled trials in which a cerumenolytic was compared with no treatment, a placebo, or other cerumenolytics in participants with obstructing 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.
Data collection and analysis
The two authors reviewed all the retrieved trials and applied the inclusion criteria independently.
Nine trials satisfied the inclusion criteria. In all, 679 participants received one of 11 different cerumenolytics. One trial compared active treatments with no treatment, three compared active treatments with water or a saline 'placebo', and all nine trials compared two or more active treatments. Eight trials included syringing as a secondary intervention.
Overall, results were inconclusive. The majority of comparisons showed no difference between treatments. Meta-analysis of two high quality trials produced a statistical difference in favour of triethanolamine polypeptide over saline in preventing the need for syringing, but no other significant differences between treatments.
In three trials of high to moderate quality, no difference was found between the effectiveness of either sodium bicarbonate ear drops, chlorbutanol, triethanolamine polypeptide oleate condensate or docusate sodium liquid versus a sterile water or saline 'placebo'.
One trial of moderate methodological quality found all three treatments - sodium bicarbonate ear drops, chlorbutanol and sterile water - to be significantly better than no treatment at preventing the need for syringing.
None of the higher quality trials demonstrated superiority of one agent over another in direct comparisons.
Trials have been heterogeneous and generally of low or moderate quality, making it difficult to offer any definitive recommendations on the effectiveness of cerumenolytics for the removal of symptomatic ear wax. Using drops of any sort appears to be better than no treatment, but it is uncertain if one type of drop is any better than another. Future trials should be of high methodological quality, have large sample sizes, and compare both oil-based and water-based solvents with placebo, no treatment or both.