Torsade de point and prolonged qt syndrome

This is actually an old problem: Indeed, one of the medications mentioned, cisapride, was taken off the US market years ago.
Torsade de point is a nasty arrhythmia...hard to treat....and can be caused by all sorts of problems...mainly renal failure with high potassium levels.
It was first noted as being a drug related problemwhen Seldane, the first non drowsy anti allergy medicine, was released. It interacted with Erythromycin and killed some people. So seldane was taken off the market too (too bad: it was the only "non drowsy" anti histamine that didn't make me drowsy!).
However, the problem with Haldol and anti psychotics were not as well known. I was aware the death rate on these strong medications was higher than normal, but have never seen a torsade de point, although have had patients on them die sudden death...(rare).
But the problems of the antibiotics Erythromycin and Biaxin are not limited to only this problem.
They also interfere with other drugs. When I worked at the states school for the retarded, I did a study showing that the new antibiotic Biaxin increased the tegretol level in our patients.
We had an epidemic of mycoplasm pneumonia (I had this too) and we knew erythromycin made a lot of our client throw up...not to mention we had to cut the dosage of those on Tegretol.
So we used biaxin. No one threw it up, but even though we cut the dosages of tegretol down in anticipation of interaction, we found biaxin was just as bad as erythromycin.
So I wrote it up and published it...
The bad news is few ordinary docs know tegretol goes to toxic levels with erythromycin...and indeed, sometimes they don't know the person has seizures or might be taking it for tic doloreux.
which is why pharmaciests are so valuable to us ordinary docs.