insomnia
"I have been taking amitriptyline for 3 and a half years since I was 12 (now 15), due to sleeping problems. I started on 10mg doses every night for the first couple of months but that didn't work so the doctors gradually increased me up to 50 mg (current dosage). They started working for a couple of months however they no longer work but I have never had any side affects. Now I get little sleep and am often feeling sick due to lack of sleep and often can no longer concentrate at school. Hope this doesn't happen to you at work."