I would really try the Morton's Epsom Lotion on this leg.

It is only $5.98 at WalMart's and quite miraculous. I get a spasm in my left neck (from strain in my job of 40+yrs holding a phone there)....just a little bit of this lotion stops this spasm within a minute or two!

It takes down my left ankle when I have swelling there, and does other nice things. My son and husband use it for back pain or over exertion problems. It has even lowered my hypertension about by 1/2 so I don't need as much medication anymore.

A little goes a long way...
http://www.mortonsalt.com/for-your-h...-epsom-lotion/

It is also on Amazon and recently someone posted that they saw it newly at Walgreen's. But I don't know the price of it at Walgreen's. I would really try this as it works locally where problems are to open the circulation and to relieve cramping.
Muscle spasms can be from low magnesium. Magnesium is the ion to relax muscles, and it also blocks the NMDA pain receptors as well.