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Rooting Out Pain
By Elizabeth Enright, September & October 2004
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Whole-Body Pain Disorders
Why It Hurts
The exact cause of generalized pain disorders is still unknown. But recently,
researchers have proven what does not cause the most common kind: fibromyalgia,
which is characterized by widespread chronic pain throughout the body, fatigue,
anxiety, and depression. For decades, fibromyalgia was believed to be a
psychosomatic disorder; only recently has it been widely accepted as a physical
condition. In 2002, a group led by Daniel Clauw, M.D., professor of medicine at
the University of Michigan in Ann Arbor, used MRI imaging to demonstrate that
fibromyalgia pain is real—people with the disorder had measurable pain
signals in their brains. Researchers now suspect a genetic component to the
disease, which tends to run in families.
What Helps
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Medicine: Currently, fibroymyalgia is treated with drugs developed for other
disorders, including a variety of analgesics, antidepressants, and muscle
relaxants. Pregabalin, which was developed as an antiseizure drug, is expected
to be approved next year by the FDA for the treatment of pain. It appears to
prevent fibromyalgia symptoms and lessen sleep disturbances, which are a major
issue in treating the painful condition. And now that fibromyalgia is seen as a
physical disorder, a number of pharmaceutical companies are conducting clinical
trials for new medications to treat it. It is hoped that several of these will
be approved within the next few years.
Cancer Pain
Why It Hurts
Pain associated with cancer can come from several different sources: the tumor
invading tissue and surrounding organs, damage from treatments such as
radiation and chemotherapy, and postoperative trauma. Although up to 90 percent
of all such pain can be treated, cancer pain is often undertreated, in part due
to doctors' and patients' concerns that patients will become addicted.
Most pain experts say these fears are misplaced. People who have never had
substance-abuse problems typically don't become psychologically addicted to
cancer-pain drugs. (Some may, however, develop a physical dependence that would
require gradual weaning if they were to stop the drug.)
What's more, in a study conducted two years ago at Johns Hopkins, the
Medical College of Virginia, and 25 other medical centers, cancer patients
whose pain was treated aggressively had better all-around outcomes than did
those who received more conservative treatment. They also had slightly better
survival rates.
Experts now agree that treating chronic pain early and aggressively yields
the best results and prevents patients from developing physical and
psychological conditions that could worsen the pain. Although there are no
conclusive studies, evidence suggests that when the cycle of pain worsens and a
person becomes psychologically desperate, they experience even more intense
pain. And it takes higher doses of painkillers to soothe pain after it has
developed than to prevent it before it begins.
What Helps
- Delivery methods: Drugs such as Avinza transform short-acting opioids into
long-acting opioids with a single capsule taken once a day, while other
medications can be administered through skin patches. Lozenges, like one called
Actiq, address sudden, breakthrough pain by delivering an opioid quickly
through the membranes of the mouth. Several pharmaceutical companies are also
working on quick-acting opioid inhalers, which are expected on the market
within the next three years.
- Combination therapy: Increasingly, oncologists are using long-acting
analgesic opioids in conjunction with other pain medications such as NSAIDs,
and coanalgesics including antidepressant and antiseizure drugs.
- Methadone: Used for more than 30 years to treat opioid addiction, this
synthetic narcotic is once again being used for chronic pain—it is an
effective substitute for morphine and is longer-acting.
- Double-duty drugs: Two chemotherapy drugs now on the market were approved
by the FDA specifically because they treat both cancer and pain. Gemcitabine is
used for pancreatic and lung cancer. Mitoxantrone is used in the treatment of
prostate cancer. "These drugs represent a completely different way of
thinking about pain management," says Portenoy of the Beth Israel Medical
Center in New York. "Typically, chemotherapy drugs are used to control the
underlying disease and prolong life, but these new drugs also improve
pain."
- Coming attractions: Ziconotide is a synthetic substance derived from the
venom of a sea snail. Phase III clinical trials have been completed, and the
drug is awaiting FDA approval. Administered to patients intraspinally through
an implanted pump, this non-narcotic is many times more potent than morphine,
without the problems of addiction or withdrawal. Drawbacks of ziconotide are
that in high doses it can alter mental states and cause low blood pressure and
dizziness. It is also expensive and hard to administer.
Further in the future are drugs based on tetrodotoxin, which comes from the
puffer fish. The injectable drugs would intercept the electrical signals
carried from nerve to nerve and prevent the transmission of pain signals,
deadening pain at the source. FDA approval may be at least five years away.
Pain is gaining new respect at all levels of health care.
And now, it is making its way onto the national political agenda. Congress has
declared this the Decade of Pain Control and Research.
Neuropathic Pain
Why It Hurts
When nerve fibers are damaged by injury or disease, pain can linger long after
the body is healed. Two of the most common forms of neuropathic pain in people
50 and older are diabetic peripheral neuropathy, a chronic condition of the
fingers and toes, and postherpetic neuralgia, which can follow a bout of
shingles. Neuropathic pain does not respond well to conventional
painkillers.
What Helps
- Double-duty drugs: Because they quiet electrical stimuli in the body,
anticonvulsants such as Neurontin are among the most effective medications for
this type of pain. Antidepressants such as Paxil have also proven helpful. But
these drugs are not fully effective, they don't help everyone, and they can
have unpleasant side effects.
- Surgery: When doctors can determine a mechanical cause for nerve
irritation, an operation can help. Trigeminal neuralgia, which is characterized
by excruciating pain in the eye, jaw, and head, can be caused by a blood vessel
that presses on the trigeminal nerve near its root. Microvascular decompression
surgery, in which the nerve and blood vessel are separated and a small Teflon
implant is placed between them, can end the pain.
Doctors cannot yet ease every ache, but they get closer by the day. Pain is
gaining new respect at all levels of health care. Hospitals risk losing their
accreditation if they don't assess a patient's pain, which is now
regarded as the "fifth vital sign," along with blood pressure, heart
rate, temperature, and breathing rate. And medical schools are beginning to
teach physicians-in-training about pain. In cutting-edge California, a state
law even requires most physicians to take 12 credits of pain management.
Now, pain may be making its way onto the national political agenda. Congress
declared 2001 through 2010 the Decade of Pain Control and Research to raise
public awareness of pain and its impact on sufferers, their families,
health-care costs, and productivity. Moreover, a bill now before Congress would
establish a national center for pain and palliative-care research and ensure
that people on Medicare and Medicaid have access to pain diagnosis and
treatment. Although the chance of passage this year is slim, advocates say
it's a first step in putting pain on the national radar screen. "Until
now, there has been no organized lobby beating on the doors of congressional
leaders," says Robert Saner, Washington, D.C., counsel for the Pain Care
Coalition. "We're hoping this can be a vehicle around which pain
constituencies and patients can organize."
Elizabeth Enright wrote about divorce in the July-August
2004 issue.
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