No... Letrozole compounds in the body... That's why we advise that you start using letrozole 2 weeks before the start of a cycle.. so that serum levels will be elevated to coincide with the start of the cycle.
If you stop Letrozole 4 days before PCT... and start Nolva at PCT.. then the letro will reduce Nolva levels by 47%
I'd advise you switch to another AI (like Aromasin.. or if you can't source aromasin.. switch to proviron... or a-dex) about 2 weeks before the end of your cycle... run that up to the poitn before PCT.
Then start PCT in the normal fashion.
Review this Letro faq:
http://www.rxmed.com/b.main/b2.pharm...F)/FEMARA.html
For activity info.
~Narkissos