Originally Posted by glenntaj

--regarding weight gain on Pregabalin (Lyrica), gabapentin (Neurontin) and most of the other anti-seizure drugs is that since most act by downregulating neural signalling, especially in the central nervous system, the hypothalamus reacts as if the body needs more nutrients to "wake it up", and produces hunger signals.

I've also heard people claim that these drugs act as if the body is going into a sort of winter hibernation and that causes a craving for especially carbs to "get through the winter". I know I certainly carb craved (more than usual) while on Neurontin.

We really don't know the exact mechanism behind the appetite increase/weight gain effect, but it certainly has been noticed as a common side effect of these drugs. Moreover, some of the weight gain may also be due to fluid retention, which is another side effect commonly reported with these. That effect may have to do with the fact that these meds are generally excreted whole through the kidneys, without going through appreciable metabolization by the liver (and why one needs good kidney function to take them).