Using Drugs to Control Cancer Pain
Drugs will be given based on whether your pain is mild, moderate, or severe.
Your doctor will prescribe drugs to help relieve your pain. These drugs need to be taken at scheduled times to keep a constant level of the drug in the body to help keep the pain from coming back. Drugs may be taken by mouth or given in other ways, such as by infusion or injection.
Your doctor may prescribe extra doses of a drug for pain that occurs between scheduled doses of the drug. The doctor will adjust the drug dose for your needs.
A scale from 0 to 10 is used to measure how severe the pain is and decide which pain medicine to use. On this scale:
- 0 means no pain.
- 1 to 3 means mild pain.
- 4 to 6 means moderate pain.
- 7 to 10 means severe pain.
Other pain scales that use happy or sad faces may be used for those who have trouble giving their pain a number. These scales are useful for adults who have trouble with memory or thinking, and with young children.
Acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) may be used to relieve mild pain.
Acetaminophen and NSAIDs help relieve mild pain. They may be given with opioids for moderate to severe pain.
Pain relievers of this type include:
- Celecoxib.
- Diclofenac.
- Ibuprofen.
- Ketoprofen.
- Ketorolac.
Side effects of NSAIDs include stomach, kidney, heart, and blood problems. Patients, especially older patients, who take acetaminophen or NSAIDs need to be closely watched for side effects. For more information, see Treating Cancer Pain in Older Patients.
Opioids are used to relieve moderate to severe pain.
Opioids work well to relieve moderate to severe pain. Some patients with cancer stop getting pain relief from opioids if they take them for a long time. This is called tolerance. Larger doses or a different opioid may be needed if your body stops responding to the same dose. Tolerance of an opioid is a physical dependence on it. This is not the same as addiction (psychological dependence).
Since 1999, the number of prescriptions written for opioids and the number of deaths caused by drug overdose in the United States have increased. Although most patients who are prescribed opioids for cancer pain use them safely, some patients may become addicted to opioids. Your doctor will monitor your opioid doses so that you are treated for pain safely.
There are several types of opioids:
- Buprenorphine.
- Codeine.
- Fentanyl.
- Hydrocodone.
- Hydromorphone.
- Methadone.
- Morphine (the most common opioid for cancer pain).
- Oxycodone.
- Oxymorphone.
- Tapentadol.
- Tramadol.
The doctor will prescribe drugs and the times they should be taken to best control your pain. It is important that patients and family caregivers know how to safely use, store, and dispose of opioids.
Most patients with cancer pain will receive opioids on a regular schedule.
Opioids are given on a regular schedule to help relieve the pain and keep it from getting worse. The amount of time between doses depends on which opioid you take. The best dose is the amount of opioid that controls your pain with the fewest side effects. If opioid tolerance does occur (the opioid no longer works at the dose you are given), the dose may need to be increased or a different opioid may be prescribed.
There is evidence that patients who are prescribed long-acting opioids (for example, medications that work for 8,12, or 24 hours), are more likely to take them as directed.
Opioids are given in different ways.
Opioids may be given by the following ways:
- Mouth: If your stomach and intestines work normally, medicine is usually taken by mouth. Opioids given orally are easy to use and are usually low-cost. Oral opioids are absorbed when placed under the tongue (sublingual route) or on the inside of the cheek (buccal route).
- Rectum: If you cannot take opioids by mouth, they may be given as rectal suppositories.
- Skin patches: Opioid patches are placed on the skin (transdermal route).
- Nose spray: Opioids may be given in the form of a nasal spray.
- Intravenous (IV) line: Opioids are given into a vein when simpler and less costly methods cannot be used, don't work, or are not wanted by the patient. Patient-controlled analgesia (PCA) pumps are one way to control pain through your IV line. A PCA pump allows you to control the amount of drug that is used. With a PCA pump, you can receive a preset opioid dose by pressing a button on a pump that is connected to a small tube. Once the pain is controlled, the doctor may prescribe regular opioid doses based on the amount you used with the PCA pump.
- Subcutaneous injection: Opioids are injected into the fatty layer of tissue just under the skin.
- Intraspinal injection: Opioids are injected into the fluid around the spinal cord. These may be combined with a local anesthetic to help some patients who have pain that is hard to control.
There are common side effects caused by opioids.
Your doctor will discuss the side effects with you before opioid treatment begins and will watch you for side effects. The following are the most common side effects:
- Nausea.
- Drowsiness.
- Constipation.
Nausea and drowsiness most often occur when opioid treatment is first started and usually get better within a few days.
Opioids slow down the muscle contractions and movement in the stomach and intestines, which can cause hard stools. To keep the stool soft and prevent constipation, it's important to drink plenty of fluids, increase fiber in the diet, and get regular exercise. Unless there are problems such as a blocked bowel or diarrhea, you will be given a treatment plan to prevent constipation and other digestive problems while taking opioids.
Other side effects of opioid treatment include the following:
- Dry mouth.
- Vomiting.
- Low blood pressure.
- Dizziness.
- Trouble sleeping.
- Trouble thinking clearly.
- Sedation.
- Delirium or hallucinations.
- Muscle jerks.
- Seizures.
- Hyperalgesia.
- Trouble urinating.
- Breathing problems that may get worse with sleep apnea, obesity, or when taking opioids with sedatives.
- Severe itching.
- Problems with sexual function.
- Hot flashes.
- Depression.
- Hypoglycemia.
Opioids are more likely to cause damage to the nervous system in patients with the following risk factors:
- Taking morphine or codeine.
- Older age.
- Kidney problems.
- Infection.
- Dehydration.
Talk to your doctor about side effects that bother you or become severe. Your doctor may decrease the dose of the opioid, change to a different opioid, or change the way the opioid is given to help decrease the side effects. For more information about coping with these side effects, see the following:
- Gastrointestinal Complications
- Nausea and Vomiting and Cancer Treatment
Other drugs may be added to help treat your pain.
Other drugs may be given while you take opioids for pain relief. These are drugs that help the opioids work better, treat symptoms, and relieve certain types of pain. The following types of drugs may be used:
- Antidepressants.
- Anticonvulsants.
- Local anesthetics.
- Corticosteroids.
- Bisphosphonates and denosumab.
Patients will not always respond in the same way to these drugs. Side effects are common and should be reported to your doctor.
Bisphosphonates (pamidronate, zoledronic acid, and ibandronate) are drugs that may be given when cancer has spread to the bones. They are given as an intravenous infusion and combined with other treatments to decrease pain and reduce risk of broken bones. However, bisphosphonates sometimes cause severe side effects. Talk to your doctor if you have severe muscle or bone pain. Bisphosphonate therapy may need to be stopped.
The use of bisphosphonates is also linked to the risk of bisphosphonate-associated osteonecrosis (BON). For more information, see Oral Complications of Cancer Therapies.
Denosumab is another drug that may be used when cancer has spread to the bones. It is given as a subcutaneous injection and may help prevent and relieve pain.