In the past 20 years, a host of new pain medications have become available. These new formulations give people with chronic pain more options than ever. But all drugs can have side effects that limit how they're used.
Two strategies can guide your use of pain medications:
The following are among the most common drugs used for chronic pain:
Description: Acetaminophen is a safe and mild pain reliever when used in moderation.
Side effects: If you drink alcohol regularly, high doses of acetaminophen can cause liver damage, so be sure to tell your physician if you drink.
Examples: Aspirin, ibuprofen and naproxen
Description: NSAIDs reduce inflammation. They also relieve pain, even if there's no inflammation.
Side effects: Minor side effects associated with NSAIDs are common and include rash, nausea and heartburn; however, ulcer disease (with complications such as bleeding and perforation of the stomach) is the most common of the serious side effects. The risk of ulcers appears to be slightly lower with newer NSAIDs, such as celecoxib (Celebrex). (Alert: Two of the COX-2 inhibitors have been withdrawn from the market valdecoxib [Bextra] on April 7, 2005; rofecoxib [Vioxx] in September 2004 due to concerns about their cardiovascular safety.)
Trade name: Zostrix
Description: Capsaicin is a cream that is applied to the skin. Usually applied sparingly three or four times each day, capsaicin is used to reduce pain in the treated area. It is mostly used for nerve pain (neuropathy) or arthritis (in the fingers).
Side effects: Capsaicin can cause burning sensation on the skin. Contact with the eyes should be avoided, as it is quite irritating.
Examples: Prednisone, methylprednisolone and dexamethasone
Description: Corticosteroids are powerful anti-inflammatory drugs. They may be taken orally or injected directly into the site of nerve irritation or inflammation. In some cases of chronic back or leg pain caused by spinal stenosis, degenerative joint disease or disk disease, injecting corticosteroids into the spine (often along with an anesthetic) can reduce or eliminate the pain for weeks or months. Usually, no more than three injections per year are recommended because of the risk of side effects.
Side effects: Regardless of how you take corticosteroids, the higher the dose and the longer the therapy, the greater your risk of serious side effects, including weight gain, diabetes, hypertension, facial puffiness, osteoporosis and infection. If corticosteroids are injected, side effects include discomfort, infection and thinning or discoloration of the skin at the injection site, but these problems are quite rare when injections are not frequent.
Examples: Cyclobenzaprine, methocarbamol and carisoprodol
Description: Muscle relaxants are particularly good for treating muscle spasm, which contributes to many cases of back pain. These drugs may reduce pain by acting directly on certain chemical messengers in the brain rather than by directly relaxing muscles.
Side effects: Because muscle relaxants may act on chemical messengers in the brain, this may explain why they also cause drowsiness.
Examples: Amitriptyline, nortriptyline, desipramine and doxepin (tricyclic antidepressants); fluoxetine (Prozac); duloxetine (Cymbalta)
Description: Antidepressants likely act on chemical messengers in the brain. By doing so, they can dull pain perception. In some cases, antidepressants work by treating accompanying depression that is making chronic pain more difficult to tolerate. These drugs sometimes work well even in doses too low to treat depression.
Side effects: Side effects include dry mouth, sedation (drowsiness) and heart rhythm disturbances.
Examples: Carbamazepine, phenytoin, gabapentin, pregabalin (Lyrica)
Description: Anticonvulsants (antiseizure medications) may be particularly helpful for pain caused by neuropathy (nerve damage). Unlike antidepressant drugs, which affect certain chemical messengers in the brain, anticonvulsants also act directly on nerve tissue. They can also be effective in the absence of neuropathy.
Side effects: Sedation, liver damage and blood cell changes are the most common side effects that limit the use of anticonvulsants.
Examples: Codeine, hydrocodone, morphine and meperidine
Description: Narcotics are often used to treat severe, unrelenting pain, such as cancer pain. They are the most powerful pain relievers available and are generally used when other treatments have failed. Narcotics can be given by mouth, can be injected or can be administered by a patch, which delivers the drugs through the skin. In some cases, patients can wear a small device that feeds a trickle of narcotics into the spinal fluid through an implanted tube, or the painkiller can be delivered by a pump implanted directly into the abdomen. In general, narcotics are not used alone for chronic pain. They are often part of an approach that includes nondrug options (such as counseling and physical therapy), as well as other nonnarcotic drugs.
Research shows that many people who do not have adequate pain relief with narcotic analgesics are either receiving prescriptions that undertreat their pain or are not following the recommendations for those prescriptions because they fear side effects. For example, a study from the University of California at San Francisco interviewed cancer patients in their homes and found that fear of side effects was a major cause of inadequate drug use. In addition, fewer than a third of patients had been prescribed both as-needed and around-the-clock pain drugs as recommended by current guidelines.
Side effects: Unfortunately, narcotics can cause constipation, sedation, confusion and nausea. In susceptible persons (especially people with lung disease), these drugs may dangerously slow breathing. They can also be addictive and may require steadily increasing doses to remain effective; in the past, however, the risk of addiction for people with chronic pain may have been overestimated. Although side effects and the risk of addiction have caused some patients and their health-care providers to shy away from using narcotics, even when they may be the best way to treat severe pain, this anxiety about narcotics is gradually changing. More health-care providers are willing to prescribe these drugs when needed.
Trade name: Ultram
Description: Tramadol is a fairly new nonnarcotic pain reliever that acts in a similar way on the brain as narcotics do; it also affects levels of the chemical messenger serotonin in the brain.
Side effects: Stomach upset, an increased risk of seizures (in susceptible persons) and harmful interactions with other drugs are the most common side effects.
Examples: Lidocaine and bupivacaine
Description: Similar to novocaine, anesthetic nerve blocks may be injected into specific nerve bundles to interrupt pain signals before they are sent to the brain. The relief is usually temporary but may provide information that can lead to better treatment; if the nerve block works, for example, a second injection in the same area with a chemical that damages the involved nerve can block the signals and provide longer relief.
Side effects: The most common side effect is an allergic reaction; in addition, the insertion of a needle to inject the medication may occasionally be complicated by nerve damage, bleeding or infection.