I had Remicade infusions for about
a year. I had no side effects at first from the infusion with the one exception that it made me extremely tired for about
2 days. I just wanted to sleep. Then at the 3rd infusion I broke out in hives. They gave me a shot of benadryl and I was fine. Each of the infusions after that they gave me a good dose of benadryl before starting the infusion and I didn't break out with them again.
Most people start feeling better fairly quickly. It didn't work for me so I got no relief from my UC symptoms while on it. I had to have surgery. My mom is on Remicade for her RA and it works great for her.