Living a Healthy Life with Chronic Pain (40 page)

T
HERE ARE TWO STEPS TO MANAGING YOUR MEDICICATION
for chronic pain. First, you need to be informed about medicines in general and how to manage any medicine you might be taking. The second step is to be aware of the specific medications you are taking for your chronic pain condition and the intended goals of your treatment.

Please review
Chapters 15
before you read this chapter.
Chapters 15
contains essential information about medications in general, taking multiple medications, communicating with your doctor, nurse practitioner, or pharmacist, and self-medicating. Once you have read
Chapters 15
, you will be able to better understand the material in this chapter about specific medications and other treatments for chronic pain.

Special thanks to Dr. Norman Buckley, MD, FRCPC, Professor and Chair, Department of Anesthesia, Michael G. DeGroote School of Medicine, McMaster University, for his help with this chapter
.

Pain medicines (which are called analgesics) and other medications can be helpful for many people with chronic pain, but they do not help everybody. Also, it is rare for medication alone to eliminate chronic pain completely. And, of course, each person may respond differently to medications. In fact, for some people, pain medicines may actually worsen pain or other symptoms over time and cause unpleasant or serious side effects. That’s why it is important to balance the risks and benefits of pain medication. It is also the reason why medication is just one part of managing chronic pain along with all the other approaches discussed in this book.

Also, recall from
Chapters 15
that expecting the best from your medicines is important. If you have a firm conviction that pain medicines are not for you, speak to your doctor. Your pain medicines are unlikely to work to best effect if you have negative beliefs about them. Instead focus on the many other ways to manage your pain and symptoms.

In this chapter, we talk about the medicines most commonly used to treat chronic pain and other symptoms. We do not talk about medicines that treat underlying disease conditions. (If you have angina pain, see
Chapters 19
.)

Some chronic pain is the result of a known disease process. Rheumatoid arthritis is an example. The underlying cause of the pain is well understood, and there are established treatments for that cause. Medication taken to treat the disease process may also reduce the pain from the disease.

But many chronic pain conditions are not the result of a well-understood disease (see
Chapters 1
). The pain itself is the “disease” or the condition. With these types of pain problems, medicines are given not to treat a specific disease but to help reduce pain, increase comfort, manage other symptoms, and improve everyday functioning.

When doctors or other health care providers prescribe medication for pain, they first need to decide on the most likely origin of the injury or potential injury that results in pain. The two major pain classifications that doctors use are called nociceptive pain and neuropathic pain.

Nociceptive pain is a result of damage or potential damage to tissues of the body, such as skin, muscle, joints, and bones. Nociceptive pain is also referred to as tissue-related pain. Nociceptive pain is usually due to an injury or illness that causes inflammation. Inflammation is a normal biological response: more blood is sent to the site of injury; chemicals are released that stimulate nerve endings, making the area more sensitive and painful; and fluid accumulates, causing swelling. The body’s inflammatory response to injury is essential for healing, but when inflammation does not disappear over time, it can result in chronic pain. Common examples of nociceptive or tissue-related pains are back pain, whiplash, and arthritis.

Neuropathic pain is usually due to damage or potential damage to nerves or the central nervous system itself. This can involve the abnormal firing of nerves anywhere between the tips of your
fingers or toes to the top of your head. Neuropathic pain is also referred to as nerve-related pain. Some examples are nerve damage after surgery or traumatic accident, post-stroke pain, shingles, diabetic neuropathy, and phantom limb pain.

Some people experience a combination of nociceptive and neuropathic pain after some surgeries or other injuries. It can also develop when pain from damaged tissues persists for a long time and leads to changes in the central nervous system and brain, which causes the body to interpret even normal sensation as painful.

Understanding the type of pain you have—whether it’s due to actual or potential tissue damage, nerve damage, or both—will help you better understand why your health care provider suggests certain medications and not others for you.

As discussed in
Chapters 4
and
5
, mood disorders such as depression and anxiety can affect how a person responds to pain. So can schizophrenia, obsessive compulsive disorder, post-traumatic stress disorder, and addiction to alcohol or other drugs. These conditions can also affect how a person will respond to pain medication. While addressing a chronic pain condition, it is important to recognize and treat these other conditions with appropriate medications or counseling as well. Even if depression or anxiety did not appear until the pain condition started, these mental health conditions may be sufficiently severe that they should be treated specifically and not just left to “get better” when the pain gets better. That is why it is essential to talk with your health care providers about how you are feeling emotionally, along with how the pain is affecting you physically.

Over-the-counter (OTC) medicines are those you can purchase without a prescription. It is important to
always
read the labels and know what the ingredients mean. Many over-thecounter medications contain ingredients that are the same as or similar to those contained in prescription medications, just in different (usually lower) doses. For example, many cold remedies also contain acetaminophen or aspirin. Some natural supplements for pain contain things like willow bark extract, which is the original source of acetylsalicylic acid (ASA or aspirin). To prevent or minimize drug interactions or the potential for overdose of some substances, your doctor and pharmacist need to know all the medications, natural products, and supplements you are taking. Review
Chapters 11
and
15
for more suggestions on communicating with your health care provider about medication.

Recall that nociceptive pain typically results from actual or potential damage to tissues due to an injury or illness. Examples of nociceptive pain include lower back pain, whiplash, and arthritis. Various types of medications are prescribed for nociceptive pain.

The medical treatment for mild nociceptive (tissue-related) pain often begins with over-the-counter topical pain relievers. These are also called topical analgesics. These come in many forms—creams, liniments, gels, sprays, and patches. You apply them to your skin over a painful muscle or joint. They work by stimulating nerve endings to cause feelings of warmth, cold, or even itching to close the pain gate. There are many of these products on the market. Talk to your doctor, nurse practitioner, or pharmacist about which topical analgesic might be best for you.

Always read the label—as you should with all medications. Some topical agents contain a nonsteroidal anti-inflammatory drug (NSAID), such as diclofenac in over-the-counter Voltaren
^®
. Other topical medicines contain aspirin-like substances called salicylates that can cause the same adverse effects as aspirin if taken in large quantities. If you are already taking aspirin or NSAID tablets—either prescription or over-the-counter—do not use topical pain relievers without telling your doctor. You may be exceeding the recommended daily dosage of these drugs if you take pills and apply a lotion or rub.
Do not
apply a topical analgesic to a wound, to broken skin, or to the face. After application, be sure to wash your hands to avoid getting these products in your eyes.

Another related group of pain relievers is overthe-counter analgesics such as acetaminophen (Tylenol
^®
, Panadol
^®
) or NSAIDs such as aspirin, ibuprofen (Motrin
^®
, Advil
^®
), and naproxen (Aleve
^®
). As we just noted, NSAID is the brief way to refer to a nonsteroidal anti-inflammatory drug. NSAIDs are the drug of choice if your pain is due to inflammation. Even though these drugs are easy to purchase, they have potentially serious side effects, including stomach upset and bleeding, and they can affect your body’s blood clotting ability. If you have a history of stomach ulcers, kidney problems, or risk factors for heart disease or are taking blood thinners, you need to be careful with these medicines. In addition, if you smoke, drink alcohol, or are over 65 years of age, you need to be careful taking aspirin or any NSAID. Talk to your doctor or pharmacist about safe dosages.

If you take acetaminophen, the amount you take is very important. Too much can cause liver problems in some people. This is a potentially serious issue for those who drink alcohol daily. Too much acetaminophen can also increase the risk of high blood pressure, heart attack, kidney problems, and bleeding ulcers. Discuss the amount you should take with your health care provider.

In some countries, such as Canada, you can buy over-the-counter acetaminophen or aspirin together with low-dose codeine (such as 222s or Tylenol
^®
#1) in pharmacies. Codeine is an opiate (see “Opioid Medications” later in this chapter) and can cause constipation and drowsiness.

Some versions of over-the-counter NSAIDs are obtained by prescription. They are usually given for mild to moderate nociceptive pain due to injuries or inflammation. Examples include diclofenac (Voltaren
^®
) and indomethacin (Indocid
^®
, Indocin
^®
). The same precautions for over-thecounter NSAIDs apply for these medications. If
you are older or have had stomach ulcers, kidney problems, high blood pressure, or risk for heart disease, use with caution. Always take NSAIDs with food, and always report stomach upset to your doctor right away. Sometimes a doctor may give you a medication to protect your stomach when prescribing these drugs. Some NSAIDs also come in a prescription topical form to rub into painful joints or muscles. Pennsaid
^®
, for example, contains a higher concentration of diclofenac than over-the-counter Voltaren
^®
.

COX-2 inhibitor drugs are a newer group of NSAIDs. Celecoxib (Celebrex
^®
) appears to have less risk of causing stomach ulcers than other NSAIDs, but it has been shown to increase the risk of cardiovascular problems such as heart attack. Your doctor will assess your risk of cardiovascular problems before prescribing this drug.

Muscle spasms can be a problem with such pain conditions as chronic neck or lower back pain and fibromyalgia. Spasms can also add to the discomfort for people with multiple sclerosis or spinal cord injuries. Medications such as baclofen (Lioresal
^®
), cyclobenzaprine (Flexeril
^®
), tizanidine (Zanaflex
^®
), methocarbamol (Robaxin
^®
, OTC Robaxacet
^®
), and others can provide some relief from muscle spasm, and some have pain-reducing properties as well. For people with musculoskeletal pain such as neck and back pain, these medications may be most helpful for acute flare-ups. They are not generally recommended for chronic pain.

The main side effects of all muscle relaxants are drowsiness and dizziness. These medicines do not work directly on the muscles; rather, it is thought they work at the level of the brain and cause sedation. Avoid driving, operating machinery, or other activities that require alertness until your response to drugs is known. These drugs should be taken with caution if you are on opioids. (We discuss opioids in more detail later in this section.)

Tramadol (Tramacet
^®
, Ralivia
^®
, Zytram
^®
, Tridural
^®
) is similar to opioid pain relievers (see below). It is available with or without acetaminophen.

Tramadol has been available internationally for almost 30 years and is used for many types of moderate to severe pain, including lower back pain, osteoarthritis, fibromyalgia, and some neuropathic pain (see
page 273
). The side effects of tramadol are mainly drowsiness, nausea, and headaches, but it does not involve the same risks of stomach, liver, heart, or kidney side effects as NSAIDs or acetaminophen. Tramadol may interact with some kinds of antidepressants to increase certain side effects. These can be mild, such as shivering or diarrhea, or more serious, such as muscle rigidity or seizures. Talk to your doctor or call 911 right away if these serious side effects occur. The risk of addiction is low for tramadol.

Tapentadol (Nucynta
^®
, Nucynta
^®
ER) is a drug with two actions, one on opiate receptors (see below) and the other on receptors common to some anti-depressant medications. It is used to treat moderate to severe chronic pain.

Opioids are among nature’s most powerful pain relievers. There is evidence that these drugs can benefit some people (but not all) who have severe chronic pain. Opioid medications are manufactured synthetically as well as from the sticky sap of poppy seed pods. Your body contains several types of receptors for these drugs (called opiate receptors), and different drugs have slightly different effects depending upon which receptor is most strongly affected by the drug. Examples of prescription opioids include codeine, oxycodone, morphine, hydromorphone, fentanyl, methadone, and buprenorphine. Except for methadone, these are all short-acting drugs. Some of them are available in slow-release forms as patches that release medication over several days to a week.

Opioid abuse is a growing problem. To get “high,” some people crush or chew tablets for a more rapid onset and greater effect. This has led to the creation of so-called “tamper resistant” formulations such as OxyNEO (oxycodone), as well as restrictions on the availability of some drugs to reduce the rising number of overdose deaths.

Doctors administer opioids by starting with a low dose and then gradually increase the dose. They do this within certain limits until the chronic pain is relieved or unacceptable persistent side effects occur or the drug is not working. Examples of opioid side effects are nausea, dizziness, sleepiness, confusion, and constipation. Most of these side effects can be reduced or made more tolerable by carefully managing the dosage. Starting at a low dose is important because when taken in too high a dose at first, opioids can cause severe breathing problems. In extreme cases, breathing can even stop.
Table 16.1
lists very important guidelines to follow when you are prescribed opioids by your doctor.

When people first start taking opioids for pain or when their dose is adjusted, they must be very careful driving or using machinery until they become accustomed to the effect of the new dose. Most people also have to take some medication for constipation while taking opioids. When taken as directed, opioids do not usually cause any stomach, heart, liver, or kidney damage even over many years of use. However long-term studies in Europe show some evidence that using opioids over years may alter hormone function in both men and women. Hormonal changes may impact mood, sexual function, and fertility and increase fatigue and pain. Long-term opioid use may also accelerate osteoporosis.

Table 16.1
Opioids: Minimizing Risks

Opioids can be part of a safe overall plan for pain management, but when you use them, you must take care and pay attention.

Current guidelines from the United States and Canada (see Other Resources at the end of this chapter) suggest that most patients achieve adequate pain-relieving effect with a dose between 50 and 120 mgs per day of morphine or its equivalent in another drug. Higher doses increase the risk of side effects and complications, up to and including death from overdose. If higher doses of opioids are considered, it should be done only in consultation with a qualified pain specialist.