You are not likely to get much help on this forum, as it is mostly dead. However, a lot of info on leg cramps is available here:

http://answers.google.com/answers/threadview/id/707090.html

The HCTZ you mentioned is a diuretic, which is one of the things that could possibly cause cramps in certain cases. A blood test your doctor could do would help to figure out if that could be an possible explanation.