You'd think that by now we'd know all there is to know about the side effects of sulfa drugs, wouldn't you? These were the top-flight antibiotics about 80 years ago, remember, and they've been in use (in one form or another) ever since. But some people have had pronounced CNS side effects from their use, and it's never been clear why.
Until now, that is. Here's a new paper in Science that shows that this class of drugs inhibits the synthesis of tetrahydrobiopterin, an essential cofactor for a number of hydroxylase and reductase enzymes. And that in turn interferes with neurotransmitter levels, specifically dopamine and serotonin. The specific culprit here seems to be sepiapterin reductase (SPR). Here's a summary at C&E News.
This just goes to show you how much there is to know, even about things that have been around forever (by drug industry standards). And every time something like this comes up, I wonder what else there is that we haven't uncovered yet. . .
