I needed Cogentin for akathesia--made it immediately disappear, what a relief. This was during the first week I started it. I had nausea and fatigue, too, but it went away. I remember the initial side effects being rough but they disappeared after two weeks. I gained no weight. I later had slightly blurry vision for a few months, it's listed as a rare side effect. I decided to keep taking the med as it kept me stabilized - the blurry vision completely disappeared a month later.