What Causes Vomiting Along With Leg Spasms?

My friend went to treatment for medication she was on. I m not sure what it was, but it would make her sick when she stopped taking it. She would throw up and have leg spasms really bad. Treatment did not work, is there a medication she could take to help her get threw the sickness? And anything I can do to help? I really want to help her get threw this and she is trying.