How is memantine/nameda improving my sense of smell?

February 7, 2020 2:11 PM

I'm 56 and for all of these years had a very strong sense of smell. I didn't realize it had diminished until my doctor game me memantine off-label for trigeminal neuralgia. Overnight I have what my spouse calls "X-Men level" smell and I'm catching things I've not smelled in years. It's often uncomfortable. My doctor has never seen this side effect before. You're not my doctor of course. I'd like to be able to suggest the mechanism whereby this is happening or even other anecdotal reports. Could it possibly be a sign of early dementia?
posted by rcMAC to Health & Fitness (7 answers total)

Not the same at all; but when I take my migraine meds (maxolt. Spelling?) I always notice that I have an improved olfactory sense...... So maybe it is related?
posted by mightshould at 3:11 PM on February 7, 2020

Some studies suggest a correlation between loss of sense of smell and pre-symptomatic/prodromal dementias. Since you don't have the memory recall issues (which are supposedly connected to the oflactory dysfunction) that namenda is meant to address, perhaps you're getting some kind of superboost in those pathways?

Here is a list of early signs/symptoms of dementia. If you or your spouse are noticing any of these, it's a good idea to have a cognitive screening regardless.

IANAdoctor and especially NAneurologist, but I'm interested to see what others have to say in response to your question!
posted by assenav at 3:49 PM on February 7, 2020 [1 favorite]

Hyperosmia (Healthline) is a heightened and hypersensitive sense of smell that has been associated with a number of medical conditions.

Hyperosmia (Richard L. Doty, Steven M. Bromley, in Textbook of Clinical Neurology (Third Edition), 2007, via ScienceDirect)

What’s That Smell? What You Need to Know About Hyperosmia (Cleveland Clinic)
posted by katra at 4:22 PM on February 7, 2020

Are these real smells, or phantom smells?

On a mechanistic level, memantine is an NMDA antagonist. Hallucinations, including olfactory hallucinations, can happen. Conversely, given the close linkage of smell and memory (cf Proust's madeleine), and the fact that memantine's primary role is for the treatment of dementia, a boost in smell awareness makes sense to me.
posted by basalganglia at 5:04 PM on February 7, 2020 [1 favorite]

Response by poster: I HAVE noticed definite changes in memory especially where words and time are concerned. Sorry I FORGOT to mention that. : ) I can be sure it's not hallucinations because younger people smell the same things and I ask "Do you smell anything?" rather than "Do you smell (whatever the thing is). Also I smell one thing in particular in the same context I did just 3 years ago. There's no question that these are real smells.
posted by rcMAC at 7:38 AM on February 8, 2020

Response by poster: I forgot to mention this all started when I happened upon science about the correlation between dementias and loss of smell. They say smell begins to diminish years and sometimes decades before other signs.
posted by rcMAC at 10:21 AM on February 8, 2020 [1 favorite]

Response by poster: Sorry...I mean my concern started then. I'd already stopped taking the med.
posted by rcMAC at 4:25 AM on February 9, 2020