It has very serious side effect potential, fda recently upgraded their warning to an even more serious one because of patient activism including parents of children who have been harmed. Scary stuff. Check it out. If your relative is good then good but I've read can also start when withdrawing from the med, and even a couple years into it if I remember correctly? These were patient stories and articles and not gone into detail about on the short warning. I don't know if there's been official guidance from any organizations to not prescribe it unless absolutely necessary but I may have read that's where things are moving after the upgraded warning, if it hasn't already? I personally felt like it was the cause of the insomnia I was having, took it for a month. There were too many changes in my life to be sure, but I don't think I did well with it. I've been checking out herbs that inhibit leuketrien.