Complex regional pain syndrome (CRPS) is a neurological disorder characterized by chronic pain. Patients suffering from CRPS experience severe pain that is out of proportion with any injury and worsens over time, as described by the National Institutes of Neurological Disorders and Stroke (NINDS). There are two types of CRPS, type I is also known as reflex sympathetic dystrophy (RSD) and occurs in the absence of a specific known injury. Type II carries the same symptoms, but is related to the injury of nerves. There is no cure for RSD, according to NINDS, but medications are prescribed to help treat the symptoms including burning pain, stiffness and swelling.
Analgesics
Analgesics are medications that work to reduce pain. The strongest analgesics are the narcotics. Narcotics work by binding to the pain receptors and blocking the pain signals from being sent to the brain, according to American RSD Hope. Examples of narcotic analgesics commonly used to treat RSD include oxycodone, hydrocodone and morphine.
NSAIDs
The exact mechanism of action of RSD is not known. The presence of redness and swelling in the affected area leads doctors to theorize that the immune system plays a role in RSD, according to NINDS. Because of the presence of swelling, prescribing non-steroidal anti-inflammatory drugs, known as NSAIDs can help to reduce the symptoms. Common NSAIDs include ibuprofen, aspirin and naproxen.
Antidepressants
Tricyclic antidepressants such as amitriptyline are the oldest form of drug used to treat depression. These medications can also be helpful in managing pain, according to The Pain Clinic, an online consumer information network. Tricyclic antidepressants can be effective in treating the nerve pain of RSD by affecting the levels of certain chemicals in the central nervous system including noradrenaline.
Antispasmodics
Antispasmodics, also called muscle relaxants, are helpful in treating the symptoms of RSD. Many patients with RSD experience muscle spasms which aggravate the pain. Medications such as benzodiazepine, clonazepam and zanaflex are prescribed to alleviate these spasms and aid in pain control.
Anticonvulsants
Anticonvulsant medications such as gabapentin and pregabalin, are often used to treat sympathetic nerve pain such as what is present in RSD, according to The Pain Center. These medications help to stabilize the nerve membranes by blocking some ion channels, which are important for transporting signals between nerves.
NMDA Antagonist
Doctors are studying the effectiveness of using ketamine, a drug that blocks the N-methyl-D-aspartate (NMDA) receptors in the brain to treat RSD. When activated, these receptors contribute to the pain response. By blocking NMDA receptors, however, ketamine can help to provide pain relief. Information provided by the International Research Foundation for RSD indicates that ketamine is effective at relieving pain without causing physical dependency, tolerance or side effects such as constipation.
