My wife had a shivering fit during the night lasting about an hour, so acute that she was calling out with every spasm. She also felt sick and retched but only brought up bile. She is 83 and because of a urinary infection has started on a course of tablets four times a day called Nitrofurantoin 50mg. Would the tablets be the cause of two consecutive nights of indigestion with the shivering session just last night? Thanks.