Chronic pain afflicts approximately 10% -
20% of the adult population. Forms of chronic pain include:
Neuropathic pain, diabetic neuropathy, post herpetic neuralgia, post
mastectomy pain, reflex sympathetic dystrophy (RSD or Complex Regional
Pain Syndrome), and phantom limb pain musculoskeletal (back, knee, hip)
pain, Fibromyalgia, Migraine, Rheumatoid arthritis, Osteoarthiritis,
Cancer pain.
Until this time, treatment for pain has relied heavily on the use of
non-steroidal anti-inflammatory drugs (NSAIDs) and opioid analgesics.
When administered by the most appropriate route and in the best dose for
the particular patient, these therapies can be beneficial. However,
other options may be more effective for a particular form of pain, or
may be used to control pain when NSAIDs or opioids are inadequate or
cause unacceptable side effects.
Neuropathic pain can be used as an example to illustrate the complexity
of and potential for effective pain management. Neuropathic pain can be
caused by multiple types of injury including blunt trauma, crushing
injury, injections, untreated inflammatory conditions and others.
Abnormal electrical impulses to be perceived within the central nervous
system. Perception may be tingling, burning, or numbness. Neuropathic
pain is characterized by invoking of pain by non-painful stimuli (such
as the touch of clothing) and exaggerated pain response, and is very
difficult to manage. Symptoms may not be evident for weeks to months
after the injury. The likelihood of effective management worsens as the
symptom duration increases; therefore, prompt evaluation and treatment
are vital. Neither NSAIDs nor opioids are effective in the management of
most Neuropathic pain. In recent years, as pain secondary to nerve
injury has been better understood, drugs that are not primarily
analgesics have been shown to be useful. Optimal treatment may depend on
the use of adjuvant medications that possess pain-relieving properties,
including some antidepressants, anticonvulsants, antiarhythmics,
anesthetics, antiviral agents, and NMDA antagonists. By combining
various agents which utilize different mechanisms to alter the sensation
of pain, physicians have found that smaller concentrations of each
medication can be used or that the previously prescribed dosages are
more effective.
