I was an anastrozole for a month and quit because of the side effects, I was miserable. It took 6 to 8 weeks for most of the side effects to cease. They told me after a month the drug would be out of my system, which may well be true but these drugs affect so much it just takes longer to come back, for the body to readjust to what it was. At least that was true for me. I started Tamoxifen and so far I’ve tolerated it well, dosage is 20 mg.