Elavil is the brand name while amitriptyline is the generic.
Elavil was discontinued in 2000 with no explanation offered. Dispensed now by the generic name only.
You are correct that it tends to help with sleep since it can make you drowsy, and it is recommended not to take after 8 PM.
When I used to take it years ago along with cyclobenzeprine, I did have an overwhelming sleepiness, and fell into a deep but disturbing sleep, marked by an often specific repetitive, intensely frightening nightmare. Did not go cold-turkey, I got help from neurologist to taper off this drug and a couple of others. There are caveats regarding foods, supplements, and health conditions. For people who can tolerate amitriptyline, it can be beneficial.