Navigation Links
2 drugs protect hearing better than 1

Whether on a battlefield, in a factory or at a rock concert, noise-induced hearing loss is one of the most common hazards people face.

Researchers at Washington University School of Medicine in St. Louis have identified a low-dose, two-drug cocktail that reduces hearing loss in mice when given before they are exposed to loud noise. The drugs, already FDA-approved for other conditions, also treat hearing loss after noise exposure.

While both drugs are known to protect hearing on their own, this is the first study to test the two in combination.

"We found they have synergy," says Jianxin Bao, PhD, research associate professor of otolaryngology at the School of Medicine. "Two drugs at lower dosages can block more signaling pathways than one alone, improving results while reducing side effects. We got the idea from cancer and HIV studies that use multiple drugs at lower dosages."

Bao presented the work Feb. 21 in Baltimore at a meeting of the Association for Research in Otolaryngology.

In earlier work, Bao's group found that anticonvulsant drugs for treating epilepsy helped protect hearing in mice after exposure to loud noise. And other groups had determined that glucocorticoids, anti-inflammatory drugs often used to treat allergies and asthma, were also protective.

The reasons these drugs reduce noise-induced hearing loss are not well understood. But anticonvulsants are known to block calcium channels in nerve cells, and Bao's group speculates that the drug helps protect neuronal connections between hair cells and auditory neurons.

For this work, Bao and colleagues chose two drugs from the anti-epilepsy family and two from the glucocorticoid family.

"We picked drugs that have fewer side effects and that can be chronically used," says Bao, also associate professor of audiology and communication sciences.

To test each drug's ability to prevent hearing loss, they gave various doses to mice two hours before exposing them to noise. To test treatment, they administered the drugs to different groups of mice 24 hours after noise exposure.

Three of the four drugs showed increasing protection with higher doses. And two of the drugs in combination, the anticonvulsant zonisamide and the glucocorticoid methylprednisolone, showed comparable hearing protection at much lower doses than when administered alone.

While the drugs do not prevent all hearing loss following sustained exposure to noise at 110 decibels, or about the sound of a chain saw, they can significantly reduce the loss by about 10 to 30 decibels.

In other words, a mouse with normal hearing might be able to hear a sound at 30 decibels. After exposure to loud noise, that mouse might only hear sounds that reach 50 decibels. But if that mouse were treated, it might be able to hear sounds at 40 decibels. In humans, protecting 5 or 10 decibels makes a difference in being able to hear everyday speech.

Bao says their next step is to test the drugs in animals that model human hearing more closely.


Contact: Julia Evangelou Strait
Washington University School of Medicine

Related medicine news :

1. The private sale of drugs in public hospitals
2. Social Anxiety and Panic - Alternative Treatment to Drugs and Therapy
3. Adapting to clogged airways makes common pathogen resist powerful drugs
4. Diabetes Drugs Avandia, Actos Tied to Fractures in Women
5. Drugs That Shift Cells Energy Find New Purpose
6. FDA Tightens Controls on Anemia Drugs
7. FDA Issues Warning on Key Asthma Drugs
8. Two Tulsa Pharmacies Penalized for Missing Prescription Drugs
9. Tests to Measure Safety of Anti-Clotting Drugs of Limited Value
10. Notch-blocking drugs kill brain cancer stem cells, yet multiple therapies may be needed
11. Scans Might Monitor Success of Alzheimers Drugs
Post Your Comments:
(Date:11/25/2015)... (PRWEB) , ... November 25, 2015 , ... ... ) has focused on providing comprehensive solutions involving adult stem cell therapies to ... has officially deemed the “Regenestem” name as a Registered Trademark (RTM). , Organizations ...
(Date:11/24/2015)... ... November 25, 2015 , ... Genesis Chiropractic Software helps practice ... an agreement between the practice owner and the patient that automatically manages all ... projections. Click here to learn more. , According to ...
(Date:11/24/2015)... ... 2015 , ... New patients who wish to seek treatment for missing teeth ... at her Mississauga, ON practice. Dr. Williams has been providing dental service for over ... , Missing teeth can lead to a variety of complications if they are not ...
(Date:11/24/2015)... , ... November 24, 2015 , ... ... launched their Black Friday sale a week early, offering 40% off select bras ... the intimate apparel industry through both mobile fit technology and the latest fashion, ...
(Date:11/24/2015)... ... November 24, 2015 , ... DMG Productions announced that they will feature ... quarter 2016 via Discovery Channel. Dates and show times TBA. , Aphria, Inc., is ... the business of producing and supplying medical marijuana pursuant to the Marijuana for Medical ...
Breaking Medicine News(10 mins):
(Date:11/24/2015)... -- The hope of bearing a child ... cycles. After failure of over 15 IVF cycles, Mrs. ... hopes that she would be able to conceive ever. But finally optimism prevailed as she ... of over 15 IVF cycles. India ... one last attempt with Gaudium IVF Center in New ...
(Date:11/24/2015)...  Thanks to a donor with a personal connection ... Sister Diane Grassilli Center for Women,s Health now offers ... San Francisco . Fred Ruhland ... a gift of $617,320 that allowed the Center to ... and Whole Breast Ultrasound. Tomosynthesis, three-dimensional (3-D) mammography for ...
(Date:11/24/2015)... Colo. , Nov. 24, 2015  Array ... that its Chief Executive Officer, Ron Squarer ... Healthcare Conference in New York.  The public is ... webcast on the Array BioPharma website.Event:Piper Jaffray Annual ... , Wednesday, December 2, 2015Time:1:30 p.m. Eastern Time ...
Breaking Medicine Technology: