The time, for me, depending upon where I had it done. When done at the hospital, I was there no less than 8 hours. It was ridiculous and frustrating.
When at my doc office, I usually was there 4-5 hours. The drip only took 2.5-3 hours. They took it a lot slower my first infusion, though.
I reacted after 2.5 years on the drug, but had no side effects or anything before that. And I did not take premeds until I had a problem (I refused them).
When I reacted, my heart rate went up, I turned bright red, and I had difficult breathing. We slowed it way down, took some Benadryl, and resumed it.