People usually feel pain when receptors in skin, bones, joints, or other tissues are stimulated by an injury or threat to the body. Neuropathic pain is triggered by changes in the nerves themselves or caused by changes in the brain or peripheral tissues.
Pain involves the interaction between several chemicals in the brain and spinal cord. These chemicals, called neurotransmitters, send nerve impulses from one nerve cell to another. Neurotransmitters stimulate receptors found on the surface of nerve and brain cells, which function like gates, allowing messages to pass from one nerve cell to the next. Many pain-relieving drugs work by acting on these receptors. For example, opioid drugs block pain by locking onto opioid receptors in the brain.
Other drugs, such as non-steroidal anti-inflammatory drugs (NSAIDs), control pain outside the brain. These drugs – including aspirin, ibuprofen, and naproxen – inhibit hormones called prostaglandins, which stimulate nerves at the site of injury and cause inflammation and fever. Newer NSAIDs, including Celebrex (celecoxib) for rheumatoid arthritis, primarily block an enzyme called cyclooxygenase-2. Known as COX-2 inhibitors, these drugs may be less likely to cause the stomach problems associated with older NSAIDs. Their long-term effects are still being evaluated.
Fear of Addiction
Helen Dearman of Houston suffered from chronic pain cause by an injury she experienced in her early 20s. One of her biggest fears was of becoming addicted to pain medications.
"It's a common concern for both patients and health providers," says Seddon Savage, M.D., a pain specialist at Dartmouth Medical School, who specializes in addiction. "Most forms of chronic pain respond to non-opioid drug treatments," she says.
Examples of non-opioid pain relievers, which don't have addiction potential, include aspirin, acetaminophen, ibuprofen, naproxen, and other non-steroidal anti-inflammatory drugs. A combination of different types of analgesic medications at lower doses is often more effective than a single high-dose medication.
"But if opioids are prescribed for your pain, you are not abusing drugs if you are taking the medication as prescribed," Savage says. "Taking doses of drugs to relieve pain is not the same as taking drugs to get high."
Opioids are controlled substances that are potentially addictive. Pain medications containing opioids include Vicodin (hydrocodone), OxyContin and Percocet (oxycodone), MS-Contin (morphine), Tylenol #2, #3 and #4 (codeine), and the Duragesic Patch and Actiq (fentanyl).
June Dahl, Ph.D., director of the American Alliance of Cancer Pain Initiatives and professor of pharmacology at the University of Wisconsin-Madison Medical School, says she took a call from a man with cancer who said he stopped taking an opioid pain medication on his own for fear that he was becoming addicted. "What he described were not signs of addiction, but signs of physical dependence," Dahl says.
Psychological Addiction versus Physical Need
Addiction is characterized by craving and compulsive use of drugs. Physical dependence occurs when a person's body adapts to the drug. If someone has become physically dependent on a drug and suddenly stops taking it, withdrawal may occur. These symptoms can include muscle aches, watery nose and eyes, irritability, sweating, and diarrhea. Physical dependence is a normal response to repeated use of opioids and is distinct from psychological addiction.
Savage says that in prescribing potentially addictive medications, doctors should consider patients' personal and family histories of addiction, as well as psychological and social stressors that may affect medication use. Also, some people who begin taking opioid medications for pain as prescribed may later discover that they are using the medication for its psychic brain effects. Physicians need to be aware of this potential adverse effect, and should educate patients and their families about appropriate use of addictive drugs.
To better guide physicians, the Federation of State Medical Boards adopted guidelines for the use of controlled substances for pain treatment. The guidelines advise physicians on patient evaluations, treatment plans, and medical records.
The use of opioids in pain treatment remains controversial for several reasons. The rate of addiction in the properly treated pain population is unknown. The media has highlighted the problems of celebrities who are addicted to pain medicine. And there has been considerable drug abuse involving OxyContin, which the FDA approved for moderate-to-severe pain. The FDA strengthened its warnings for oxycodone, while continuing to recommend appropriate pain control for people living with severe pain.
But experts say that finding a balance between cracking down on drug abusers and protecting people in pain is an ongoing struggle. "Some doctors fear regulatory scrutiny for over-prescribing these drugs," Dahl says. "And concerns about the small segment of people who abuse drugs ends up interfering with effective pain management for others."
Sheryl Kaufman, 40, of Boston, who uses oxycodone and a fentanyl patch for severe pain associated with breast cancer, says she recently filed a grievance with a pharmacy over her struggles to get prescriptions filled. "They made me feel like a criminal," she says. "Sometimes I've had to go without pain medication for two to three days because of delays in filling prescriptions."
The Value of Support
Dearman's experiences with chronic pain led her to establish the National Chronic Pain Society. The organization provides peer support for people with chronic pain and their families. "We give people support for dealing with all of the issues that can go along with chronic pain – not having your pain taken seriously, frustration over not finding relief, how to communicate your pain to your doctor, and how to maintain relations with your family," Dearman says.
Penney Cowan, founder of the American Chronic Pain Association, another peer support organization, says support systems are important because they give people with pain the coping skills needed to take an active role in their recovery. "Sometimes doctors tell people they'll have to learn to live with the pain," Cowan says. "But too often they stop short of telling them how to accomplish that."
Dearman says finding effective treatment and gaining the skills to live with her pain made all the difference. "It's about being a person first and not letting pain define who you are," she says. "Our motto is: Pain may be unavoidable, but suffering is optional." |
