Drug may help troops battle combat-related hearing loss

Prolonged exposure to excessively loud noise, such as rock concerts or power tools, or exposure to traumatic levels of noise for a short period of time, such as gunshots or airplane noise.

Results ...

Hair cells become damaged and, over time, destroy themselves after a traumatic noise event. Total destruction of the affected hair cells usually occurs within a three-week period after the traumatic noise event.

If hair cells die, the ear registers less sound, which means fewer signals are sent to the brain, resulting in hearing loss.

What the two-drug mixture does ...

It produces antioxidants that stimulate hair cells to repair themselves after a traumatic noise event rather than allowing the hair cells to destroy themselves. This allows the ear to remain close to the same level of hearing as it did before the traumatic noise event.

Sources: Hough Ear Institute and Oklahoma Medical Research Foundation. McClatchy-Tribune Information Services

NAC has been used for years to combat Tylenol overdoses because it helps stop liver cells from dying by producing glutathione, an antioxidant. The antioxidant restores the liver cells rather than letting them die.

The same thing happens with hair cells in the ear, Kopke said. NAC helps the body produce more glutathione, which keeps hair cells in the ear from dying and retains hearing after exposure to traumatic noise.

4-OHPBN nitrone

Although Floyd and Kopke are unsure what role the nitrone plays in hearing loss prevention, Kopke said the results of the two-drug combination are far better than the results of administering NAC alone.

It is thought the nitrone deals more with nitrogen-related toxins, but both drugs could "work on several other things that could be playing a role,” Kopke said.