An epidural's duration depends on its purpose and the medication used. For back pain relief via epidural steroid injections, the pain relief effect typically begins within a week and can last anywhere from a few weeks to up to 12 months. Usually, multiple injections might be given a few weeks apart, and the effect can gradually reduce pain over time. For labor epidurals, the relief lasts as long as the catheter is in place and medication is administered, commonly about an hour or two per dose, and can last throughout labor for several hours or up to five days if continuously administered. After stopping the medication, the numbness can take a few hours to wear off. In summary:

• Epidural steroid injections for back pain: pain relief lasts from a few weeks to up to a year.
• Labor epidurals: pain relief lasts as long as medication is being delivered, several hours to up to a few days.
• The immediate numbness or anesthesia effect wears off within hours after stopping the epidural.

This variation is due to the different types of epidurals and medications used.