http://www.psychiatrist.com/JCP/article/Pages/2018/v79n01/16r10749.aspx

The conclusion that staying on the initial antidepressant and pushing up the dose seems real-world and switching more a pharmaceutical grab and unneccessary stressor for the patient.
Often, though, people are not on a med for 6 weeks (nonresponse definition) but 6 months, 6 years….That is a different kettle of fish.
So, in sum, don’t panic, stick with what you started, and see if the results pan out at 6-8 weeks before considering a switch. This study again argues that SSRI have flat-dose response curves.
40 prozac = 225 effexor clinically. (150mg by receptor profile)