Taking Namenda? Should I take Robitussin or Robitussin DM?

Well, today is the day I raise my dose of Namenda from 15-mg up to 20-mg. I’m supposed to take 10-mg twice daily. Since I’ve had a robust response to this drug overall, I’ll be very curious to see how the increased dose will work.


Are you taking Namenda? The prescribing information and package insert for Namenda contains this statement: The combined use of Namenda with other NMDA antagonists (amantadine, ketamine, and dextromethorphan) has not been systematically evaluated and such use should be approached with caution.

DM stands for dextromethorphan. DXM is another abbreviation for it. It is a cough suppressant which is chemically related to codeine. It isn’t addictive and it doesn’t work for pain though. It’s an active ingredient in over 120 nonprescription cough and cold medications. When used in normal doses it is usually OK. It’s a good over the counter agent for coughing, etc. Most people don’t have any problems so I’m not intending for the average person to stop using it or to scare anyone. It is usually safe in the 15- to 30-milligram dosages recommended for treating cough or colds. It is a very good agent when used safely!

This is the drug that teenagers are now abusing and getting “high” from. In high doses (100-milligrams or more), it can cause a mildly euphoric and stimulating effect similar to that of ecstasy. At even higher doses, the drug’s “stoning” effect increases and hallucinations may occur. The highest plateaus are characterized by ELABORATE HALLUCINATIONS AND OUT-OF-BODY EXPERIENCES. During such out-of-body experiences, users perceive a complete disconnection from their body and surroundings, WITH NO AWARENESS OF WHAT THEY ARE DOING (OR HAVING DONE TO THEM).

Even in normal individuals, especially the elderly and those with dementia, it can also cause confusion, impaired judgment, loss of coordination, paranoia, excessive sweating, psychosis, brain damage, rigid muscle tone or involuntary muscle movement and decreased ability to regulate body temperature, which can lead to heat stroke. Other side effects can be severe dizziness, anxiety, restless feeling, or nervousness, slow, shallow breathing, dizziness, nausea, seizures, panic attacks, and addiction, coma and death, blurred vision and/or slurred speech, numb fingers or toes, dry mouth, itchy skin, irregular heartbeat and high blood pressure.

The take home message is this. Individuals with dementia already have a lot of the above symptoms. And they are more sensitive and susceptible to them when taking the DM form of Robitussin. If you are not sure whether to take this or not, please check with your physician.

DXM products are known in the street as Skittles, Red Devils, Robo (from Robitussin) or Triple C’s. The high that dextromethorphan produces is called “robotripping” or “skittling.”

Robitussin is one of the brand names for guaiphenesin. It is usually the main ingredient in many of the “tussin” drugs. It is a common over the counter  drug which dissolves thick mucus sold over the counter and usually taken by mouth to assist the bringing up (“expectoration”) of phlegm from the airways in acute respiratory tract infections. The active ingredient in Mucinex and Robitussin is guaiphenesin. So, Robitussin becomes Robitussin DM when dextromethorphan is added to it.

Guaiphenesin also comes in tablets which are easier to take. I try to avoid the thick liquid cough syrups. Bitter tasting medicine!

By the way, when it comes to these old fashioned medications, I personally prefer the generics. They are much cheaper and just as effective as the brand names. Only my opinion.

Now, that I am on Namenda, I’ll have to be cautious this winter. I’ve always relied on the long-acting form of dextromethorphan for my coughs such as Delsym. Never had much luck with the regular dose of dextromethorphan which is in the Robitussin DM form. Guess I just try a small dose of it when I need it in order to make sure all is well.

(I have no financial interest in any of the above mentioned medical products).



8 Responses

  1. My Dad has LBD and back in January he got sick. We took Dad to the doctor and the doctor told him to take Mucinex. We gave it to him for a few days and he had the most horrible reaction to it and ended up in the hospital. It was an absolute nightmare beyond belief. We learned a very hard lesson and we are now extremely cautious with what is given to Dad- even if the doctors recommend it- you just never know.

  2. Very very interesting. In my entire medical career, I’ve never seen any side effects. I looked it up on several sites. They all say it is one of the safest medications available and that any side effects are RARE.

    I guess it goes to show how our bodies are all different!


  3. David,
    I am pretty sure that you should only take the plain Robitussin.Again,I am sure that one of the more knowledgeable members on the Yahoo site will tell you more.But,don’t be looking for any colds/coughs this winter.Think positive.

  4. That’s really interesting. In my Dad’s case I wonder if it had to do with the warning on the Mucinex box and the Parkinsonism & depression of his LBD. Dad takes prescriptions drugs for both issues. On the warning label, it says, “Do not use if you are now taking a prescription monoamine oxidase inhibitor (MAOI) (certain drugs for depression, psychiatric, or emotional conditions, or Parkinson’s disease).”

    From now on, whenever we see a warning like this, Dad doesn’t take it. Everyone is different so you just never know how one will react but Mucinex does have that PD/ depression warning… who knows? The doctor obviously knew Dad’s condition and still thought it would be okay for him.

    I enjoy reading your blog- keep up the great work!

  5. Hi David,

    Hope you have had some decent sleep.

    Thankyou very much for the info/warnings. I will watch what the Dr suggests for Dad’s (LBD/ALZ) problems with phlegm.


  6. I believe that Namenda has been approve by the UDFDA for only a few years now/ You should see the contraindications list for Namenda Plus Aricept which I was on for a 2 yr study at Ohio State.
    Study finished and I stopped the Arecept with its GI complications and feel mauch better just on my 10mg bid Namenda.

    I’m from Chicago as a youngster and did my grad work at UW Madison …. so I envy you your snow

    Dan in Dayton

  7. Hm…just found this, and know this might be ‘old news’ by now, but just found that namenda & DM should NOT be taken together.

    My dad (90.5, AD/dementia dx) was taking guafenisin @ the nursing home; now that he’s home, I was hoping that DM might be helpful in quelling his cough (since he no longer has pneumonia). No go.


    Serious – Use Alternative.
    memantine & dextromethorphan.
    Either increases toxicity of the other by pharmacodynamic synergism. Serious – Use Alternative.

  8. Husband on Aricept and Namenda. Has a bad cough. Have Mucinex DM 12 hr. ..Should I give it to him for Cough??? Need to know.

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