Dextromethorphan - Cough Suppressant

[futurehope]

I had taken Mucinex which contained the above cough suppressant as well. Normally, I would avoid the dextro... but my husband had used the combo medicine and it was in the house.

I noticed it "suppressed" by blood pressure and heartrate, both coming out way below my normal. I felt yech and luckily I had some cortef (hydrocortisone - adrenal hormone) in the house and took a bit of that to normalize my stats.

Has anyone else noticed a reaction to cough suppressant? Needless to say, I'm going to avoid it from now on.

BTW, I'm not really sick anymore. I was using the Mucinex to loosen congestion. I did not need the dextro part.

[poppetkazutaka]

I had taken Mucinex which contained the above cough suppressant as well. Normally, I would avoid the dextro... but my husband had used the combo medicine and it was in the house.

I noticed it "suppressed" by blood pressure and heartrate, both coming out way below my normal. I felt yech and luckily I had some cortef (hydrocortisone - adrenal hormone) in the house and took a bit of that to normalize my stats.

Has anyone else noticed a reaction to cough suppressant? Needless to say, I'm going to avoid it from now on.

BTW, I'm not really sick anymore. I was using the Mucinex to loosen congestion. I did not need the dextro part.

I think that's the stuff that's in NyQuil and they tell you not to take it with beta blockers. I take it anyway because NyQuil is the only thing that works on my stuffy nose when I'm sick, and helps me to sleep when I'm not able to breathe when I'm sick. So far it hasn't crashed me out too much...

[ramakentesh]

I had it once at university and I took too much and it made me kind of 'trip' or what I assume a 'trip' feels like. Very strange stuff. Didnt help the cough though LOL. This was before I came down with POTS.

[erik]

I'm sure there are plenty of other possibilities, but one thing to keep in mind is the CYP2D6 metabolism. Many drugs rely on it (either to activate or to clear out), some inhibit it, some promote it, and people can have genetic variability of this too. It can apparently be involved in regular food metabolism, though drug aspects are more commonly documented and examined for interaction.

DXM happens to rely on 2D6 enough that it's used as a means of measuring that enzyme's activity level! If you are a slow metabolizer the drug could stay around longer and perhaps induce different effect than typical (though I guess DXM is more associated with tachycardia rather than brady, but who knows). It could impact other drugs, like competing for 2D6 activity and making both clear out slower or preventing the activation of another drug (if it's a prodrug) or changing the duration of an extended release drug (if it's relying on varying half-lives of metabolites).

In the case of a beta-blocker this could be key (maybe making both act longer & more intensely??? professional advice would be good to seek of course). Glucocorticoids happen to promote 2D6 activity, so in addition to inherent help from the cortisol boost, perhaps it helped prompt your liver to clear the DXM quicker too!

[futurehope]

Erik,

I really did not understand your post. But when I look at the list of drugs in relation to CYP2D6, I have trouble taking those drugs. I don't know really what it means? Does a CYP2D6 gene aid in metabolizing a drug, and I'm deficient in that gene?!

[erik]

It's a possibility. I guess about 5-10% of people are abnormal metabolizers. If you see a pattern like that from the chart then it seems possible. Of course, allergy or some other sensitivity or interaction is always a posibility... I just mention this because it's fascinating to me and shocked me that it is not all that uncommon.

Also, some drugs will then inhibit or promote whatever natural metabolic rate you have, or fight over a limited amount of enzyme activity... which can explain some drug interactions. Here's another chart... maybe it's the same info, I'm not sure:

http://medicine.iupui.edu/clinpharm/ddis/ClinicalTable.asp

I personally suspect that I am deficient because I am "immune" to codeine & vicodin, which require 2D6 activity to turn in to their working form! More commonly, the 2D6 is working to remove a drug from the system, though. A "slow metabolizer" might end up with a higher and longer lasting dose compared to a "normal". An "ultra rapid" metabolizer might get only brief benefit, then be left with just side-effect fallout.

There is genetic testing (probably pricey but definitive) and there's clinical tests. I don't know how common testing for this is. In one case they give you a dose of DXM then measure it's level in your blood to see how fast you "metabolize" it. I think one of the anti-estrogen drugs is also used this way.

[csnell325]

extremely sensitive to it my heart goes crazy and then all the other symptoms kick in shortly after its put me in the hospital once or twice too b4 i realize what it was

[skyblu]

Yes...I'm very senstive to it. I took Robitussin DM a few years ago and got tachy from it. I do fine with regular Robitussin which is basically just Mucinex.