Addendum:
Actemra wasn't abruptly stopped and Humira started. I was doing Actemra injections every two weeks at the time. My instruction was to do a Humira injection instead of an Actemra injection whenever my next Actemra injection was due. Otherwise the transition to Humira was seamless.

The idea was I couldn't have both medications in my system at the same time. Actemra had to be mostly out of my system before Humira was started.