I’m pretty much beat today, you can read a nicely written piece on it over at CBS News, but the breakdown is this more or less: If your kid’s under two years of age don’t use any sort of numbing agent for teething pain.
There’re two separate warnings going on, the first one involves very stupid cancer patients or people with access to cancer patient medication (in this case viscous lidocaine,) for mouth sores giving babies adult prescription medication. If you’re dumb enough to be doing that you’re probably not reading this.
The other involves over the counter numbing agents such as Orajel that contain benzocaine also can lead to a potentially fatal condition called methemoglobinemia. Basically insanely lowered oxygen content in the blood which can kill ’em.
This second warning is aimed at children under two years of age.
As far as I can tell if you’ve used one of these gels before, you’re not at lowered risk for the problem happening in the future. It could have been happening in the past and you just didn’t catch that your baby went to sleep because of the lowered oxygen levels causing them to pass out, not because of the pain relief. So yeah, just because it’s worked before don’t trust it to not cause problems.
The FDA suggests teething rings, cold things, all the stuff you’ve probably tried and realized didn’t work for you baby so you went and bought a gel.
The products that were named by brand name (according to the CBS report,) are Anbesol, Hurricaine, Orajel, Baby Orajel and Orabase.
So yeah, nothing you do to attempt to help your baby will ever not be linked to potentially killing them. There’re other articles that mention checking with a doctor, who will probably either give you the teething ring advice or tell you how to spot the signs of methemoglobinemia.