insomnia
"I have been taking amitriptyline for about 9 years now. I always take 10 mg. I read there are people who take a very high dosage.
In a high dosage it does not work for insomnia but for depression. It is better to start with 10 mg.  When you start taking them you can have side effects, but these will disappear in time.
When you are very busy in your head, it is possible that it won't work that night. But don't give up. I take it about 2.5 hours before going to bed.
But don't use a high dosage, it won't work for your insomnia. It is an excellent pain killer as well, in a lower dosage. 
And with 10 mg it is very easy to stop taking it, I did that a couple of times  without any problems."