I have been on amitriptyline for 5 years and tried to come off it unsuccessfully a number of times, each time causing a return of my old symptoms. I was initially prescribed it for PND and insomnia. I have now increased it back up from 100mg to 150mg at night.. How long does it usually take to kick in and when do the side effects such as feeling spaced out and nauseous subside? I cannot remember from the last time I reduced then increased again, but it has me worried this time?