Why are the letters "z" and "x" so popular in drug names?

> Warning: TV Tropes wiki. Do you need another time sink?

You're not kidding. Lost an hour the first time I innocently followed a link there.

I refuse to click that link. I'll just guess the contents based on the title.

This is what I heard years ago from the doctors in my family when the first z/x name drugs started emerging.

Interesting. Do you think it's the same reason car manufacturers always put either 'z' or 'x' into the model name for a 'sporting model'. The list is endless, it's easier to find a sports model without these additions. Coverage is near-complete if you add 'GT' and/or R into the list, but these speak to 'grand touring' and 'racing', whereas 'z' and 'x' do not.

My father, a clinical psychiatrist, tells me that he has read in the British Medical Journal (the publication linked in the OP) of a study that had drug names as its variable. They gave many patients the same drug, but gave it to them under a variety of differently constructed names. He says that this study found that names beginning with X and Z produced a greater efficacy than any other letter. Unfortunately he can't remember anything else about it, I am working on finding out more.

I know this is a lame excuse for not citing sources but still, its very interesting, and personally I trust my father :)