Hi wakey,

From a quick look, it seems Horizant is generic Gabapentin, and is extended release.

Firstly, don't stop taking it without your Doc's knowledge, and I would mention your concerns re: stone legs feelings to your Doctor and get his/her advice as to whether you should continue.

The main difference to watch out for with extended release medication is more drowsiness than you are used to.

With regular pain medications the cover is like a roller coaster. About an hour after taking them you get the most benefit but also the most side effect including drowsiness. Over several hours the pain relief, and any side effects, will slowly lessen as the drug wears off (usually around 6-8 hours). So there are approximately 4 hours there where you are operating on very little, if any, pain relief medication. This gives your body a break.

With extended release there is approximately 25% of drug in first hour or so, then the remaining 75% of drug slowly entering your system over the remaining hours. Therefore you never get a break from the effects of the drug. The upside is you get more consistent pain relief. But the obvious downside is you may feel drowsier for longer, and this will obviously intefere with driving ability.

I recently started taking extended release Tramadol at night only. In this way, during the day I had more control of drowsiness via taking regular Tramadol, but the extended release would give me better coverage at night.

I did find it took a few weeks to adjust, and for the first week or so my legs did feel heavier. Knowing this may happen, I planned to start this new regime during a holiday break.