The AudioNotch Tinnitus Treatment Blog

Memantine is an NMDA channel blocker and is undergoing intense research to determine if it has high potential for treating tinnitus through pharmacological solutions. Research is studying the effect of memantine on NMDA currents that impact neurotransmissions and is evaluating the impact of memantine on the auditory brainstem response. The hope is that memantine for tinnitus will become a successful and common treatment option.

Maintaining Neurotransmitter Balance

Most people refer to tinnitus as a ringing in the ears. It is usually initiated by hair cell or nerve damage in the ear, called acoustic trauma. Other possible causes include:

• Ear injuries like a perforated eardrum or damaged hair cells
• Middle ear disorders
• Certain diseases like diabetes or abnormal blood pressure
• Medications, including anti-inflammatories, antibiotics and antidepressants

Brain nerve cells communicate through neurotransmitters which are natural compounds or chemicals. The compounds attach to nerve cell receptors that accept only one particular type of neurotransmitter.

Everything must be in balance and working properly. For example, the ear’s inner hair cells and the auditory nerve connected to the brain are managed by the neurotransmitter glutamate. The receptor for glutamate is N-methyl-d-aspartate (NMDA). When too much glutamate is produced, neurons end up continually firing and eventually wearing out. Throughout the process, the brain is adapting. Memantine is a NMDA receptor antagonist, suppressing glutamate activity.

Focusing on the Brain

There is a reason that researchers are focusing on the brain rather than the ear to develop a medication like memantine for tinnitus. Even when tinnitus is initiated by an ear injury, it is the new auditory pattern in the brain that perpetuates the condition. It was past research that first suggested that tinnitus is caused by neuronal hyperactivity in the brain regions responsible for the auditory sense. What was not known was whether the hyperactivity was a result of the inhibition or the stimulation of the synapses.

Scientists found that rats subjected to acoustic trauma that created a perception of tinnitus-like sounds experienced a measurable increase in brainstem-evoked responses related to hearing. When the rats were given a dose of memantine, many of the animals experienced a reduction in tinnitus-like behavior.

Memantine medication is already approved by the Federal Drug Administration for treatment of moderate to severe dementia that is usually associated with Alzheimer’s disease. It works by blocking NMDA receptors (NMDARs) which are precisely why it is under study as a potential drug for blocking cochlear NMDAs. If a medication is successfully developed, memantine for tinnitus has the potential of bringing great relief to those who suffer with tinnitus.