Basic Principles of Cancer Pain Management
Acetaminophen and NSAIDs
Opioids
        Types of Opioids
        Guidelines for Giving Opioids
        Side Effects of Opioids
Drugs Used with Pain Medications

Basic Principles of Cancer Pain Management

The World Health Organization developed a 3-step approach for pain management based on the severity of the pain:

• For mild to moderate pain, the doctor may prescribe a Step 1 pain medication such as aspirin, acetaminophen, or a nonsteroidal anti-inflammatory drug (NSAID). Patients should be monitored for side effects, especially those caused by NSAIDs, such as kidney, heart and blood vessel, or stomach and intestinal problems.



• When pain lasts or increases, the doctor may change the prescription to a Step 2 or Step 3 pain medication. Most patients with cancer -related pain will need a Step 2 or Step 3 medication. The doctor may skip Step 1 medications if the patient initially has moderate to severe pain.



• At each step, the doctor may prescribe additional drugs or treatments (for example, radiation therapy).



• The patient should take doses regularly, "by mouth, by the clock" (at scheduled times), to maintain a constant level of the drug in the body; this will help prevent recurrence of pain. If the patient is unable to swallow, the drugs are given by other routes (for example, by infusion or injection).



• The doctor may prescribe additional doses of drug that can be taken as needed for pain that occurs between scheduled doses of drug.



• The doctor will adjust the pain medication regimen for each patient's individual circumstances and physical condition.

NSAIDs are effective for relief of mild pain. They may be given with opioids for the relief of moderate to severe pain. Acetaminophen also relieves pain, although it does not have the anti-inflammatory effect that aspirin and NSAIDs do. Patients, especially older patients, who are taking acetaminophen or NSAIDs should be closely monitored for side effects. Aspirin should not be given to children to treat pain.

Opioids are very effective for the relief of moderate to severe pain. Many patients with cancer pain, however, become tolerant to opioids during long-term therapy. Therefore, increasing doses may be needed to continue to relieve pain. A patient's tolerance of an opioid or physical dependence on it is not the same as addiction (psychological dependence). Mistaken concerns about addiction can result in undertreating pain.

There are several types of opioids. Morphine is the most commonly used opioid in cancer pain management. Other commonly used opioids include hydromorphone, oxycodone, methadone, fentanyl, and tramadol. The availability of several different opioids allows the doctor flexibility in prescribing a medication regimen that will meet individual patient needs.

Most patients with cancer pain will need to receive pain medication on a fixed schedule to manage the pain and prevent it from getting worse. The doctor will prescribe a dose of the opioid medication that can be taken as needed along with the regular fixed-schedule opioid to control pain that occurs between the scheduled doses. The amount of time between doses depends on which opioid the doctor prescribes. The correct dose is the amount of opioid that controls pain with the fewest side effects. The goal is to achieve a good balance between pain relief and side effects by gradually adjusting the dose. If opioid tolerance does occur, it can be overcome by increasing the dose or changing to another opioid, especially if higher doses are needed.

Occasionally, doses may need to be decreased or stopped. This may occur when patients become pain free because of cancer treatments such as nerve blocks or radiation therapy. The doctor may also decrease the dose when the patient experiences opioid-related sedation along with good pain control.

Medications for pain may be given in several ways. When the patient has a working stomach and intestines, the preferred method is by mouth, since medications given orally are convenient and usually inexpensive. When patients cannot take medications by mouth, other less invasive methods may be used, such as rectally or through medication patches placed on the skin. Intravenous methods are used only when simpler, less demanding, and less costly methods are inappropriate, ineffective, or unacceptable to the patient. Patient-controlled analgesia (PCA) pumps may be used to determine the opioid dose when starting opioid therapy. Once the pain is controlled, the doctor may prescribe regular opioid doses based on the amount the patient required when using the PCA pump. Intraspinal administration of opioids combined with a local anesthetic may be helpful for some patients who have uncontrollable pain.

Patients should be watched closely for side effects of opioids. The most common side effects of opioids include nausea, sleepiness, and constipation. The doctor should discuss the side effects with patients before starting opioid treatment. Sleepiness and nausea are usually experienced when opioid treatment is started and tend to improve within a few days. Other side effects of opioid treatment include vomiting, difficulty in thinking clearly, problems with breathing, gradual overdose, and problems with sexual function.

Opioids slow down the muscle contractions and movement in the stomach and intestines resulting in hard stools. The key to effective prevention of constipation is to be sure the patient receives plenty of fluids to keep the stool soft. Unless there are problems such as a blocked bowel or diarrhea, patients will usually be given a regimen to follow to prevent constipation and information on how to manage bowel health while taking opioids.

Patients should talk to their doctor about side effects that become too bothersome or severe. Because there are differences between individual patients in the degree to which opioids may cause side effects, severe or continuing problems should be reported to the doctor. The doctor may decrease the dose of the opioid, switch to a different opioid, or switch the way the opioid is given (for example intravenous or injection rather than by mouth) to attempt to decrease the side effects. (Refer to the PDQ summaries on Gastrointestinal Complications ¹, Nausea and Vomiting ², Nutrition in Cancer Care ³, and Sexuality and Reproductive Issues ⁴ for more information about coping with these side effects.)

Other drugs may be given at the same time as the pain medication. This is done to increase the effectiveness of the pain medication, treat symptoms, and relieve specific types of pain. These drugs include antidepressants, anticonvulsants, local anesthetics, corticosteroids, bisphosphonates, and stimulants. There are great differences in how patients respond to these drugs. Side effects are common and should be reported to the doctor.

The use of bisphosphonates may cause severe and sometimes disabling pain in the bones, joints, and/or muscles. This pain may develop after these drugs are used for days, months, or years, as compared with the fever, chills, and discomfort that may occur when intravenous bisphosphonates are first given. If severe muscle or bone pain develops, bisphosphonate therapy may need to be stopped.

The use of bisphosphonates is also linked to the risk of bisphosphonate-associated osteonecrosis (BON). See the PDQ summary on Oral Complications of Chemotherapy and Head/Neck Radiation ⁵ for more information on BON.

Glossary Terms

A drug that reduces pain and fever (but not inflammation). It belongs to the family of drugs called analgesics.

Uncontrollable craving, seeking, and use of a substance such as a drug or alcohol.

In medicine, the act of giving a treatment, such as a drug, to a patient. It can also refer to the way it is given, the dose, or how often it is given.

A drug or other substance that causes a loss of feeling or awareness. Local anesthetics cause a loss of feeling in one small area of the body. Regional anesthetics cause a loss of feeling in a part of the body, such as an arm or leg. General anesthetics cause a loss of feeling and a complete loss of awareness that feels like a very deep sleep.

Having to do with reducing inflammation.

A drug or other substance used to prevent or stop seizures or convulsions. Also called antiepileptic.

A drug used to treat depression.

A drug that reduces pain, fever, inflammation, and blood clotting. Aspirin belongs to the family of drugs called nonsteroidal anti-inflammatory agents. It is also being studied in cancer prevention.

A drug or substance used to treat hypercalcemia (abnormally high blood calcium) and bone pain caused by some types of cancer. Forms of bisphosphonates are also used to treat osteoporosis and for bone imaging. Bisphosphonates inhibit a type of bone cell that breaks down bone. Also called diphosphonate.

The necrosis (death) of bone tissue caused by treatment with a bisphosphonate (a drug or substance used to treat osteoporosis, bone pain caused by some types of cancer, and high blood calcium). It commonly occurs in the jaw bones. There may be pain, swelling and infection in the areas of necrosis. Also called BON.

A tube through which the blood circulates in the body. Blood vessels include a network of arteries, arterioles, capillaries, venules, and veins.

The long, tube-shaped organ in the abdomen that completes the process of digestion. The bowel has two parts, the small bowel and the large bowel. Also called intestine.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

A condition in which stool becomes hard, dry, and difficult to pass, and bowel movements don’t happen very often. Other symptoms may include painful bowel movements, and feeling bloated, uncomfortable, and sluggish.

To adjust to new situations and overcome problems.

Any steroid hormone made in the adrenal cortex (the outer part of the adrenal gland). They are also made in the laboratory. Corticosteroids have many different effects in the body, and are used to treat many different conditions. They may be used as hormone replacement, to suppress the immune system, and to treat some side effects of cancer and its treatment. Corticosteroids are also used to treat certain lymphomas and lymphoid leukemias.

Frequent and watery bowel movements.

The amount of medicine taken, or radiation given, at one time.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

A condition that occurs when the body gets used to a medicine so that either more medicine is needed or different medicine is needed.

A drug used to treat severe cancer pain in that occurs even though the patient is already taking opioids. It is also used during anesthesia for surgery. Fentanyl citrate binds to opioid receptors in the central nervous system. It is a type of analgesic agent and a type of opioid.

An increase in body temperature above normal (98.6 degrees F), usually caused by disease.

A substance that flows smoothly and takes the shape of its container. Liquids and gases are fluids.

A drug used to relieve pain.

A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

Having to do with the intestines.

The long, tube-shaped organ in the abdomen that completes the process of digestion. The intestine has two parts, the small intestine and the large intestine. Also called bowel.

Within the spine (backbone).

Into or within a vein. Intravenous usually refers to a way of giving a drug or other substance through a needle or tube inserted into a vein. Also called IV.

A medical procedure that invades (enters) the body, usually by cutting or puncturing the skin or by inserting instruments into the body.

In medicine, the place where two or more bones are connected. Examples include the shoulder, elbow, knee, and jaw.

One of a pair of organs in the abdomen. Kidneys remove waste from the blood (as urine), produce erythropoietin (a substance that stimulates red blood cell production), and play a role in blood pressure regulation.

A legal drug that is used to prevent, treat, or relieve symptoms of a disease or abnormal condition.

A drug used to treat moderate to severe pain that does not respond to other types of pain medicine. It is also used to help people who are addicted to opioid drugs such as heroin. Methadone hydrochloride binds to opioid receptors in the central nervous system. It is a type of analgesic agent and a type of opioid.

A drug used to treat moderate to severe pain. It binds to opioid receptors in the central nervous system and some other tissues. Morphine sulfate is made from opium. It is a type of opiate and a type of analgesic agent.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

A procedure in which medicine is injected directly into or around a nerve or into the spine to block pain.

A drug that decreases fever, swelling, pain, and redness. Also called NSAID.

A substance used to treat moderate to severe pain. Opioids are like opiates, such as morphine and codeine, but are not made from opium. Opioids bind to opioid receptors in the central nervous system. Opioids used to be called narcotics. An opioid is a type of alkaloid.

By or having to do with the mouth.

A drug used to treat moderate to severe pain. It is made from morphine and binds to opioid receptors in the central nervous system. Oxycodone hydrochloride is a type of analgesic agent and a type of opiate.

A method of pain relief in which the patient controls the amount of pain medicine that is used. When pain relief is needed, the person can receive a preset dose of pain medicine by pressing a button on a computerized pump that is connected to a small tube in the body. Also called PCA.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

A condition in which a person takes a drug over time, and unpleasant physical symptoms occur if the drug is suddenly stopped or taken in smaller doses.

A doctor's order for medicine or another intervention.

In medicine, action taken to decrease the chance of getting a disease or condition. For example, cancer prevention includes avoiding risk factors (such as smoking, obesity, lack of exercise, and radiation exposure) and increasing protective factors (such as getting regular physical activity, staying at a healthy weight, and having a healthy diet).

Having to do with how the mind works and how thoughts and feelings affect behavior.

A device that is used to give a controlled amount of a liquid at a specific rate. For example, pumps are used to give drugs (such as chemotherapy or pain medicine) or nutrients.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

By or having to do with the rectum. The rectum is the last several inches of the large intestine closest to the anus.

A treatment plan that specifies the dosage, the schedule, and the duration of treatment.

A drug or substance used to calm a person down, relieve anxiety, or help a person sleep.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

In medicine, a family of drugs used to treat depression, attention-deficit disorder (a common disorder in which children are inattentive, impulsive, and/or over-active), and narcolepsy (a sleep disorder that causes uncontrollable sleepiness). Stimulants increase brain activity, alertness, attention, and energy. They also raise blood pressure and increase heart rate and breathing rate.

An organ that is part of the digestive system. The stomach helps digest food by mixing it with digestive juices and churning it into a thin liquid.

The material in a bowel movement. Stool is made up of food that was not digested, bacteria, mucus, and cells from the intestines. Also called feces.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

Treatment.

To eject some or all of the contents of the stomach through the mouth.

A part of the United Nations that deals with major health issues around the world. The World Health Organization sets standards for disease control, health care, and medicines; conducts education and research programs; and publishes scientific papers and reports. A major goal is to improve access to health care for people in developing countries and in groups who do not get good health care. The headquarters are located in Geneva, Switzerland. Also called WHO.