Friend have irritable leg syndrome, immediately calf and knees twinge next to charly horse contained by foot?
He has been on leg drug for several years and the severity of the calf and knee pain is increasing. He have prior neck and back injuries.
Answer: There are several possibilities for what could be cause this such as a more serious problem with the digestive tract such as Crohn's (an example only). In some conditions such as Crohn's symptoms can affect the legs and knees.
I would recommend that he get support in touch with his doctor for further evaluation of the situation to see what they articulate.