Health - DXM and Hydrobromic Acid

Discussion in 'DXM' started by El Calico Loco, Feb 16, 2007.

  1. El Calico Loco

    El Calico Loco Gold Member

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    Google gave me an MSDS for hydrobromic acid (ie, the "HBr" part of DXM HBr):

    http://www.bu.edu/es/labsafety/ESMSDSs/MSHydBromicAcid.html

    Seems like some pretty nasty stuff.

    Wikipedia tells me that the molecular weight of DXM is 271.4 g/mol. It also tells me that the molar mass of HBr is 80.91 g/mol. It's been a long time since chemistry class...so I'm not really sure what to do with these numbers. Can molar masses be added to get the overall molar mass of a compound, or is that too simple?

    Perhaps someone with a stronger background could tell us how many mg of HBr make up 100mg of DXM HBr? And does anyone know how many mg of bromides one has to build up in one's body to cause harm? Answering these two queries would go a long way toward knowing how often DXM can be taken safely, at least from the bromism angle.

    I know this subject has been broached before, but UTFSEing didn't give me any real answers...just more questions.


    ECL
     
  2. Nagognog2

    Nagognog2 Iridium Member

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    Simple: Figure out what percent of 271.4 would be 80.91. This is assuming the first number is, in fact, the mol. wt. of DXM without the HBr attached. I'm not bothering to pull out my Merck Index and reading glasses.

    So the answer is roughly 30%.
     
  3. El Calico Loco

    El Calico Loco Gold Member

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    That's what I assume as well, since the Wiki article was on "dextromethorphan" and not "dextromethorphan HBr" in particular. But if that is the case, wouldn't I have to add the two masses before finding the percentage?

    ie: 80.91 / (271.4 + 80.91) = 0.229 rather than 80.91 / 271.4 = 0.298 ? My main point of confusion is whether "molecular weight" and "molar mass" are the same; Wikipedia gives the former for DXM and the latter for HBr. Please tell me if I'm mistaken on the math.

    So...1000mg of DXM HBr would be either 229mg or 298mg HBr, depending on which of the above is correct.

    Now please indulge me, dear readers, as I try to reason my way through this.

    We have the atomic masses of the elements of the HBr compound:

    H: 1.00794 g/mol
    Br: 79.904 g/mol

    These add up to 80.91, so I'm guessing that molecular mass is the same as atomic mass - one just can't call it "atomic mass" when it's not a simple atom. *smirk*

    That would mean that 99% of the mass comes from the bromine atom (no big surprise, as hydrogen is the lightest element), leaving either 228mg or 295mg of free bromides per 1000mg of DXM HBr. That would also mean that one is only really getting 771 or 702 mg of DXM itself - which adds some interesting data to that from White's DXM FAQ, as I believe all his dosage calculations assumed DXM HBr. This might mean that dosages are different for the DXM Citrate created by the agent lemon process, as citric acid weighs in at 192.13g/mol (almost twice that of HBr), and for DXM polistirex, whose weight I don't know.

    The following PDF has a table of danger levels for bromism based on the mg/dL found in a person's blood (serum, actually, but my knowledge of medicine is not sufficient to tell the difference; all I know is that serum supposedly makes up 55% of the blood's weight):

    http://www.rand.org/pubs/monograph_reports/MR1018.2/MR1018.2.chap10.pdf

    It lists more than 50mg/dL as possibly toxic, 100-200mg/dL as seriously toxic, 200-300mg/dL as possibly coma-inducing, and >300mg/dL as possibly fatal.

    I haven't had much luck finding the exact amount of blood in a human body; google results vary from 4 to 5 liters. I suppose it might vary based on size and mass. I'll use 5L (50dL) just for simplicity.

    So...someone who takes 1000mg DXM HBr will have a maximum of 228 or 295mg of free bromides, depending on which calculation above is right. This would give a blood concentration of only 4.56 or 5.9 mg/dL, respectively. Nothing to worry about. Assuming 50dL of blood, one would need 2500mg of free bromides to reach the toxic threshold and 5000mg to reach serious toxicity. Taking enough DXM HBr at once to reach that point would kill one anyway from the massive DXM overdose alone.

    Except...

    According to Wikipedia (again), bromides take forever to excrete from the human body via the kidneys. The half-life is 12 days.

    So, let's say one takes 1000mg of DXM HBr once every 12 days. I'll calculate the bromide buildup for both possibilities above:

    Assuming 228mg,
    Bromide buildup after day 1: 228mg
    Bromide buildup after day 13: 228mg + (228mg / 2) = 342
    Bromide buildup after day 25: 228mg + (228mg / 2) + (228mg / 4) = 399
    Bromide buildup after day 37: 228mg + (228mg / 2) + (228mg / 4) + (228mg / 8) = 427.5
    Bromide buildup after day 49: 228mg + (228mg / 2) + (228mg / 4) + (228mg / 8) + (228mg / 16) = 441.75
    This continues as the bromide total asymptotically approaches 456.

    It works the same assuming 295mg, only the answer comes out to 571.6mg after day 49 and approaches a maximum of 590. I'll assume 228 from here on.

    Not too much to worry about in the short term, but probably not good for you in the long run.

    It gets worse if one does it once per week. The asymptote in this case is 686. Of course, this assumes that having so many bromides in one's body doesn't interfere with the body's ability to excrete them. Doing 1000mg once every other day leads to over 2000mg of free bromides in one's system within 55 days of this pattern. Close to the danger zone, but still not quite at the toxic level.

    1000mg DXM HBr once per day leads to 4062mg of free bromides, well within the danger zone and close to the toxic level.

    What to make of all this? Ignoring the possible dangers of DXM itself and looking at just the possibility of bromism, it seems like there's not a great deal of danger unless one is taking large doses every day or two. One could probably take a low dose every day without bromides becoming an issue. I still don't recommend it (and neither does my friend Swim, who loves his DXM), but it's possible. Nor does it seems that a high dose will cause such, so long as it's only once every couple of weeks. If one is taking large doses often or several small doses a day, then one is probably asking for it.

    The PDF linked to above gives the simple treatment for bromism: saline. The chlorides compete with the bromides and drive the little demons out. If one does too much DXM HBr and just can't stop, it might do some good to eat a little more salt than usual. Might. I don't know for sure. The PDF says that saline injections have been known to reduce the half-life of bromides from 12 days to a matter of hours.

    If one begins feeling fatigued, irritable, emotionally unstable, depressed, and incapable of short-term memory, one should go see a doctor. Later stages of bromism can lead to schizophrenic-like psychosis, hallucinations, and violent ideations. One important thing to remember is that bromism is very rare since Bromo-Seltzer went off the market; doctors don't even think to look for it. They'll probably misdiagnose the patient unless the patient is upfront about their concerns. The doctor will probably want to know why, but there's no law saying one has to tell him or her, so long as one is emphatic in demanding a test of bromide serum levels.

    Caveat: this is based on the author's limited knowledge of chemistry and physiology gained from Wikipedia and Google and a quick perl script written to iterate over the various bromide levels and use frequencies. I hope those with greater knowledge of these subjects will check my work. I also hope someone who has taken discrete math more recently than I can provide the general summation equation for this subject.


    ECL
     
  4. Nagognog2

    Nagognog2 Iridium Member

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    Allow me to save you a migraine headache (M.W. 666.66): If you take a lot of DXM.HBr - you will end up with large, disgusting pimples - which is the most obvious symptom of bromism. Read: Unless your lover gets a kick having white-heads splattering in their face - chill! Go slow. Easy Does It.

    It will clear up after one discontiunes the use of the .HBr. But for those who don't mind this effect and wish to continue - I propose a new name for those folk: Squeeze-Heads.

    <I'll go away now>