How long does it usually take for an Epidural steroid injection to alleviate a herniated disk to take effect?

My wife just received her second epidural steroid injection in her back. She has a herniated disk in her lower back. Curious as to how long it usually takes for the medicine to begin taking effect. Thanks in advance for any info.

In most epidural steroid injections a combination of local anesthetic (numbing medication, comparable to "novocaine") and a steroid is used. Some steroids like methylprednisolone (Solu-Medrol) are in crystalline form and take some time to dissolve. It also takes the nerve a couple of days to respond by decreasing inflammation and swelling.
If your wife gets only relief for a day or just a couple of days it means that the steroid is not helping and the temporary pain relief is just from the numbing medication.
If the steroid helps, it takes anywhere from 2-6 days to kick in. If there is no relief after 2-3 injections discuss other treatment options. Often epidural steroid injections given as transforaminal (coming in a little from the side versus midline) give much better relief.

An epidural steroid injection is not indicated for the relief of discogenic back pain. It may never work.

Typically if the steroid is mixed with a local anesthetic you should see immediate relief of pain. But again, epidural steroid injections are not indicated for the relief of discogenic back pain.

I have had 3 injections and after each one i had instant relief. the relief only lasted for about 72 hours though. The problem wasn't corrected, but i noticed a significant difference in the level of pain.

I have to go and get a series of 3 epideral injections in my L5 for a herniation and a tear. My Pain Specialist told me that it could be a week or 2 before I saw any relief, and that it would probibly be more sore the first couple days after having it done.