Epidural for Spondylolisthesis

Hi. I’m posting for a relative who has spondylolisthesis. She’s received 2 epidurals in her lower back and didn’t see any improvements. She went to a new pain management doctor and immediately he simply referred another epidural injection.

She’s feeling hesitant in receiving another injection that could possibly be useless. Do these infections have serious side effects?

Thanks, in advance, for your input. 😀