Honestly, you have to watch the whole movie in order to enjoy it, but if you do, I think it's a great movie, with an interesting plot.
There is some violence, although nothing horrible. Some blood, and a murder is described on a TV, although nothing is shown.
The whole movie is about a drug, that has some very serious side effects, such as lost time, among other things. And if you stop taking it, you'll die.
Anyway, this is one movie that grows more and more interesting the more into the movie you watch, but I can understand how the beginning could bore you, but in the end, it's important to the plot.
What other families should know
Too much violence
Too much drinking/drugs/smoking