Drugstore eardrop remedies could lead to hearing loss, study warns
Researchers who studied over-the-counter eardrops for softening wax buildup are warning about the possibility of hearing loss and other problems if the drops are used by someone with a perforated eardrum.
Dr. Sam Daniel, director of the McGill Auditory Sciences Laboratory at the Montreal Children's Hospital, launched the study after a patient in her 30s complained of a blocked ear. The woman had used the product Cerumenex, which can be purchased in drug stores.
"She said, 'it's strange, my ear is even more blocked than before,"' Daniel said.
"I looked in her eardrum and there was no wax. She had a big hole in her eardrum, and she lost hearing on that side," he said.
"I think she had a perforation to start."
Daniel is not concerned about use of the product by people with healthy eardrums.
"My problem with this product is it's available on the shelf, without any prescription. Anyone with a blocked ear or sensation of blockage can walk in and just put it in their ear, and they may not know that the reason they're feeling blocked — it's not a wax plug, but a perforation."
Daniel studied the medical literature and couldn't find any studies that looked at hearing loss or other problems among people who have used eardrops to break up excess ear wax.
His study, conducted on chinchillas, was published in the journal The Laryngoscope.
Among the animals with perforated eardrums, "all of them developed hearing loss, most of them developed the hearing loss after a single application, and as early as 24 hours after the application," said Daniel, an ear, nose and throat specialist from Montreal.
Animals with healthy eardrums did not experience hearing loss after the drops, but "a fair number developed inflammation of the canal and some of them got an otitis externa — the canal was weeping for a few days," he said.
He said he believes the findings from the animal model are applicable to humans because they have a similar hearing mechanism.
Randy Steffan, director of corporate affairs for Purdue Pharma, which makes Cerumenex, said Monday that the drops have been available in Canada since 1958.
The package insert specifies that the product should not be used if there's a perforated eardrum, a middle ear infection, atopic dermatitis or inflammation of the external ear, or a previous skin reaction, he said.
"Obviously, Purdue's first and over-riding concern is for the safety of consumers who use our products, so we will be following up with the team at Montreal Children's (Hospital), because we want to learn more about their study," he said from Pickering, Ont.
He said the company hadn't heard any concerns or complaints about the product similar to those cited by the researchers.
When doctors treat people with earwax buildup, Daniel said they have a number of approaches to choose from, including suctioning, gentle irrigation and using a little spoon-shaped surgical instrument called a curette.
He also said further tests are being done using other eardrops containing triethanolamine polypeptide, the same active ingredient that's in Cerumenex.