Injection therapy is usually a safe procedure, and it sometimes provides pain relief that can last for weeks or even months at a time. While patients are enjoying this pain-free period, they may be better able to complete physical therapy, exercise therapy and other rehabilitation that can help them avoid future bouts of pain.

However, side effects sometimes occur with these treatments. This may include pain, bleeding or infection at the injection site. Infection typically is indicated by fever in addition to redness, fluid or odor at the injection site. Patients who experience these symptoms are urged to contact their physician.

After injection therapy to areas around the spine, some patients may experience a spinal headache (also known as a post-dural puncture headache). This can result from spinal fluid leakage from the epidural space, which decreases fluid pressure around the spinal cord and brain, causing a headache. Movement (e.g., getting up and walking around) too soon after the procedure is associated with the onset of spinal headaches. Spinal headaches may occur days after the injection, and bed rest for a day or two following the procedure may be recommended.

The severity of spinal headaches may lessen when a patient lies down. Drinking caffeinated beverages, which constricts blood vessels and increases spinal fluid pressure, may also help relieve these headaches. In some cases, patients may need to receive intravenous fluids to increase spinal fluid pressure and relieve the headache. A blood patch, in which the patient's own blood is injected to seal the leak, may also be used to relieve a spinal headache.

There is a small risk of damage to spinal nerves that could result in neurological complications. Some patients may have bladder-control problems for an hour or two following the procedure, as the nerves of the bowel and bladder may be temporarily paralyzed following certain types of injection therapy (e.g., epidural block).

Other side effects of injection therapy may include elevated blood pressure and nausea.