Possible side effects from the injection of corticosteroids into the spine include flushing of the face and chest, sleeping problems, anxiety, menstrual changes, water retention and an increase in blood sugar in patients with diabetes. In a minority of cases, pain increases for several days, advises Johns Hopkins Medicine.
For patients taking certain medications, it is possible for steroid injections to suppress the body's ability to make its own corticosteroids. A patient who experiences side effects is advised to contact his health care provider. Serious complications are quite rare, according to Johns Hopkins Medicine, but may include an allergic reaction, bleeding, nerve damage, infection or paralysis.
After receiving an injection (an outpatient procedure), the patient usually returns to normal activities on the following day. The steroids typically begin working within one to three days, but it may take up to a week to feel the full benefits. Many people experience several months of improvement in pain and function from the injections. Johns Hopkins Medicine advises a patient who does not experience pain relief to speak with his doctor as this may mean the pain is unrelated to the spinal nerves. In this case, further testing needs to be done to determine the cause of the pain.