It’s all in the spelling

In a previous post, I made reference to drugs coming off prescription-only status, thus becoming subject to Oklahoma sales tax. The drug I had in mind when I wrote that was Xyzal (levocetirizine), which the FDA approved for over-the-counter sales earlier this year, spurring the production of annoying little TV spots like this:

I was cross-checking this with Wikipedia, which is usually at least somewhat reliable on the subject of prescription drugs, and stumbled across this bit of weirdness:

It is sold under the following brand names:

  • Xyzal in Australia, Austria, Croatia, Czech Republic, Finland, France, India, Ireland (also Rinozal), Italy, Lithuania, Netherlands, Portugal, Romania, Taiwan, Thailand, Turkey, The Philippines, Serbia, Slovakia, Slovenia, South Africa and UK. On May 25, 2007, the United States Food and Drug Administration approved Xyzal, where it is co-marketed by Sanofi-Aventis.
  • Xusal in Germany;
  • Xozal in Greece;
  • Cezera in Poland;
  • Xazal in Spain;
  • Xuzal in Mexico.

And half a dozen others that don’t sound like that.

Incidentally, Xyzal is an enantiomer of Zyrtec (cetirizine): the two molecules are mirror images of one another. Saves a bundle on research, I’ll bet.


  1. fillyjonk »

    6 May 2017 · 6:52 pm

    Hm. In some cases, the L-version of an enantiomer works, and the D-version does not. (Or, I guess they use R and S for medications? I learned D and L).

    That said: at least I now know this new thing isn’t some magical new compound that would be better for my allergies than the current mixture I take (and I have reason to believe the original zyrtec enantiomer jacked with my blood pressure)

  2. CGHill »

    6 May 2017 · 6:55 pm

    The Wiki saith R, though “levocetirizine” sounds like it ought to be the L.

  3. fillyjonk »

    6 May 2017 · 6:57 pm

    I dunno, most of my orgo/bio chem was stuff like amino acids, where they use D and L, or at least they did 30 years ago. I never went as far as drug-development in my chemistry.

  4. David W »

    6 May 2017 · 7:43 pm

    A slight error in your post: Zyrtec is actually both enantiomers while Xyzal is just the biologically active one. 10 mg of Zyrtec contains 5 mg of Xyzal and 5 mg of mirror-Xyzal. It’s a patent ploy. Although theoretically the non-active component could have side effects with no corresponding benefit, if that were the case here we’d have seen Xyzal much earlier.

    D/L vs R/S is explained by Wikipedia, it’s a question of whether you’re looking at the whole molecule or just the chirality center:

  5. CGHill »

    6 May 2017 · 8:06 pm

    I wondered why I couldn’t make this make sense. Thanks.

  6. fillyjonk »

    7 May 2017 · 7:05 am

    Ah, that’s like what someone told me about “prescription” vs. OTC loratidine: that when it went OTC, the process was changed to allow more of the “mirror” form that wasn’t active, which was why people sometimes found it less effective but with greater side effects. I never *totally* believed that explanation despite that person being a plausible source.

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