--including Gabapentin/Neurontin, should be tapered off slowly, as the possibility exists for seizure if they are suddenly discontinued.

All these drugs work, at least in part, by suppressing the activity of the central nervous system to spread nerve impulses' they upregulate the inhibitory neural transmitters to ameliorate runaway nerve signals. The body, in response, tends to upregulate its response to this suppression, meaning if the drug is suddenly stopped, there is more chance of runaway signalling occurring.

This homeostatic balance in signalling pathways happens with a lot of drugs--part of the reason opiates must be weaned off of slowly is that body similarly upregulates its pain sensitivity in response to the suppressive activity of the opiates, and a sudden removal of them allows this upregulation to respond unchecked, which is experiences as withdrawl symptoms until the body "downregulates" back to a baseline.