I've been on montelukast for a few years now and never had any problems with side effects. I've had a few different brands and noticed no difference until my latest batch. This last month I've had really wierd and vivid dreams (this bits nothing new to me really) but it's the fact I wake in the morning totally unrefreshed as though I've actually been physically doing the things in my dreams. I've also been waking during the night and generally sleeping rubbish which is meaning I'm shattered during the day. The only thing I can imagine is that is related to the different brand of montelukast. I'm due to pick my next prescription up this week and wondered if I can request not to have this brand again?