My Daughter Called, Has Frequent UTIs, Is Supposed To Take

my daughter called, has frequent UTIs, is supposed to take 1 200mg tab Pyridiem three times a day. said she took a 3 at same time. she has had to be on it from time to time the past few years. She took them 2 hrs ago and now she says she feels dizzy and weak. she has never had problems with it before. she has no other symptoms and is able to void. Is there anything we should do.