I was prescribed this drug for an upper respiratory infection...in its early stages. The first day I took it, it just about knocked out the infection so that was good. It kind of kept me awake at night but it wasn't an uncomfortable alertness. The one thing it did was to cause my limbs to go numb...like when you lay wrong on your arm and it goes to sleep. First my right arm then my left and then my left leg. Very wierd. It also made me very dizzy for a couple of hours after taking it. Like a buzz. Other than that it hasn't been too bad. I think I'll stop taking it anyway now.