Trental
"I have had significant leg pain for a long time.  This medication took about 1-2 months to start working, but then it was great.  I could run on the treadmill at much faster speeds and for much longer - when previously I'd have cramps.  Also, standing stationary used to be painful after 5-10 minutes - but this also improved.  The only problem is that this medication can cause anxiety and insomnia since it is derived from xanthine (chemical "cousin" of caffeine).  This is listed as a rare side effect on the drug insert, but I have heard it is more common from my doctor.  



I was actually given this for Peyronie's disease (off-label), but it didn't do much for that.  It is supposed to inhibit TGF-beta (a cytokine) - decreasing scar tissue."