my husband takes tizanidin for muscles spasms. he has been taking for 3 yrs. this month our pharmacy sent a different pill than usual. it is much larger than what we have always had. for the last 3 weeks my husband has started the jerking(his arm will start jerking until it shakes his entire body)again. he has not done this for some time. i called pharmacy to ask about the pill and they said that they changed manufacturers. i asked if that would make a difference because he didnt start this until we got new med. pharacist said no, but i think it is having effect on him