Certain types of back pain can be treated effectively with injections into the back. These injections are comprised of steroids, local anesthetic, or both. Steroids like Kenalog and Decadron reduce inflammation, while local anesthetics deaden the nerves that carry pain signals. These injections are not necessarily curative and may need to be repeated over time. Fortunately the majority of low back pain cases clear up with six months of the original injury. Since a single injection can last for up to six months, most people will need only one round of treatment to get back pain relief.