Injections into or near your spine help deliver pain-reducing medicines directly to the source of pain and can ease back pain or sciatica (shooting pain down one or both of your legs). The effects of a successful spinal injection can last up to three months.There are two medicines used in spinal injections. Local anaesthetic is used to completely block pain from the injected area. Steroids are used to reduce swelling and irritation (inflammation) in the injected area ...... The local anaesthetic will keep you pain-free for a while, but it's best to take things easy for the first 24 hours. After this, your back may start to feel sore again because the steroids take a few days to work. Your back pain or sciatica should start to improve within a few days of your injection.You should be able to start physiotherapy within a week of your injection. It's important to remember spinal injections aren’t a cure for back pain and it's the physical therapy that will help improve your medical condition in the long-term.