There's a cannabis-based pharmaceutical called Sativex that's approved in the UK, Canada and some other countries for use in MS spasticity and neuropathic pain. It's in a Phase III trial in the US, and I've been hoping it will get approved here but so far it hasn't.

The good thing about having something like Sativex is the THC is pure and metered so you get the same dose every time. Also it's dispensed as a mist and absorbed sublingually, which is nice for those of us who have a hard time smoking.

Here's a link for more information: http://www.gwpharm.com/Sativex.aspx