Facts about Pain Medications in Cancer Pain Treatment

Medicines used to relieve pain

The type of medicine and the way the medicine is given depend on the type and cause of pain. For example, chronic pain is best relieved by methods that deliver a steady dose of pain medicine over a long period of time, such as a patch that releases medicine through the skin or slow (extended)- release pills. On the other hand, breakthrough pain is best treated with medicines that work fast (quick release), and stay in the body only for a short time. Below is an overview of the types of medicines used to relieve pain.

For mild to moderate pain
Non-opioids: Acetaminophen (Tylenol) and non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen (Advil, Motrin), are often used.

You can buy many of these over the counter (without a prescription). For others, you need a prescription. Check with your doctor before using these medicines. NSAIDs can slow blood clotting. This may be a problem if you’re having surgery or getting chemotherapy. NSAIDs and acetaminophen may also affect other parts of the body and may interact with other medicines.

For moderate to severe pain

Opioids (also known as narcotics): Morphine, fentanyl, hydromorphone, oxycodone, codeine and others
You need a written prescription for these medicines. Non-opioids may be used along with opioids for moderate to severe pain.

For breakthrough pain

Rapid-onset opioids: Fast-acting oral morphine; fentanyl in a lozenge, “sucker,” or under-the- tongue spray (These forms of fentanyl are absorbed from your mouth – they are not swallowed.)
You need a written prescription for these medicines. A short-acting opioid, which relieves breakthrough pain quickly, is often used with a long-acting opioid.

For tingling and burning pain

Antidepressants: Amitriptyline, nortriptyline, venlafaxine, and others… You need a prescription for these medicines. Antidepressants are prescribed to relieve certain types of pain. Taking an antidepressant does not mean that you’re depressed or have a mental illness.

Anti-convulsants: (anti-seizure medicines): Carbamazepine, gabapentin, and others
You need a prescription for these medicines. Despite the name, anti-convulsants are not only used for convulsions (seizures), but also to control burning and tingling (nerve) pain.

For pain caused by swelling or pressure

Steroids: Prednisone, dexamethasone
You need a prescription for these medicines. They’re most often used to lessen swelling, which often causes pressure and pain.

How is pain medicine given?

Some people think that if their pain becomes severe, they’ll need to get injections or “shots” of pain medicine. In fact, shots are rarely given to relieve cancer pain. There are many other ways you can take pain medicine.

Oral – means the drug is taken by mouth, either by being swallowed or absorbed in the mouth. Medicine is given as a liquid, pill, capsule, or in transmucosal form (the drug is in a lozenge, “sucker,” or spray and absorbs directly through the tissues of the mouth).

Skin patch – a clear, sticky patch placed on the skin. It slowly but constantly releases medicine through the skin for 2 to 3 days.

Rectal suppositories – medicine that dissolves in the rectum and is absorbed by the body

• Subcutaneous (SC) injection – Medicine is put just under the skin using a small needle.
• Intravenous (IV) injection – Medicine goes right into a vein through a needle, port, or catheter.
• Intrathecal and epidural injections – Medicine is put into the fluid around the spinal cord (intrathecal) or into the space around the spinal cord (epidural).

Pump, or patient-controlled analgesia (PCA) – With this method, you have control over the amount of pain medicine you take. When you need pain relief, you press a button to get a pre-set dose of pain medicine through a computerized pump. (The pump carefully controls how much you can get at a time, so you can’t take too much.) The pump is connected to a small tube going into your body. The medicine goes into a vein, just under the skin, or into the area around the spine.

Different ways to treat chronic and breakthrough pain

Treating chronic pain
Drugs used to treat chronic or persistent pain need to work for a long time. They’re called long- acting or extended-release drugs and are taken at regular times. They’re slowly released into the body and keep pain at a lower level over a long period of time.

You take these pain medicines on a schedule – even if you’re not having pain at the time the medicine is due. By taking these drugs on a schedule, you can maintain a fairly constant level of pain relief through the day and night. These drugs may be given in the form of tablets or capsules taken every 8 to 12 hours or as a skin patch that’s worn for several days. Again, these drugs are taken on a schedule and not just when you’re in pain.

Treating breakthrough pain
Breakthrough pain is best treated with pain medicines that work quickly and for a short period of time. They’re usually taken as needed, which means that they should be taken as soon as you notice breakthrough pain. These short-acting drugs (sometimes called rescue medicines) work faster than those used for chronic pain. They also stay in your body for a shorter time and tend to cause fewer side effects.
You should take your short-acting medicine when you first notice pain, so that it can start to work to relieve your pain right away. Do not let the pain build up and become too severe – it will be much harder to get under control.

Follow the directions given to you. If the usual dose doesn’t relieve your breakthrough pain, or if you think you’re having breakthrough pain too often, tell your cancer care team. They may need to adjust the dose or frequency of the medicine you take for chronic pain.

Common questions about breakthrough pain

If I have breakthrough pain, does it mean that the pain medicine I’m using regularly for my chronic pain isn’t working?

No. Breakthrough pain is an intense flare-up of pain that’s usually more severe than chronic pain. Remember, breakthrough pain is common in people with cancer pain. It can happen even when a person is taking the right dose of pain medicine on a regular schedule for their chronic pain.

Still, let your cancer care team know if you’re having more breakthrough flare-ups than usual, and just how often you need your breakthrough medicine. You may need a larger dose of your chronic pain medicine.

How can I be sure that I’m getting the right dose of breakthrough pain medicine?

Your breakthrough pain medicine should relieve most of your breakthrough pain without causing unacceptable side effects, such as extreme drowsiness. If your breakthrough pain medicine doesn’t relieve the breakthrough pain or if you have breakthrough pain more than 4 times a day, contact your cancer care team. They may need to adjust your dose or type of pain medicines to help you get the best pain relief.

Can I take my chronic pain medicine and my breakthrough pain medicine at the same time?

Yes, if you need to. You may have breakthrough pain just before or after taking your regular (chronic) pain medicine. At such times, you should take your breakthrough pain medicine and keep taking your chronic pain medicine on schedule. Always follow the directions given to you by your cancer care team.

If you notice that you often have breakthrough pain right before your usual dose of chronic pain medicine, talk to your team. They may need to adjust the dose, timing, or frequency of your chronic pain medicine. If you have any questions about when to take either your chronic or breakthrough pain medicines, contact your team to discuss your pain medicine schedule.

What if I need a different pain medicine?

If one medicine or treatment doesn’t work, there’s almost always another one that can be tried. If the schedule or way that you’re taking medicine doesn’t work for you, it can be changed, too.
Some pain medicines cost more than others, and this may also be an issue. Talk to your cancer care team about finding the pain medicine and/or method that works best for you.

You may need a different pain medicine, a combination of pain medicines, or a change in the dose or timing of your pain medicines if:

  • Your pain is not relieved.
  • Your pain medicine doesn’t start working within the time your doctor said it would.
  • Your pain medicine doesn’t work for the length of time your doctor said it would.
  • You have breakthrough pain more than 4 times a day, it’s getting worse, or it’s not relieved with the short-acting medicine you’re taking for it.
  • You have side effects. Side effects such as sleepiness, nausea, and itching usually go away as your body adjusts to the medicine. Let your cancer care team know if these bother you.
  • You have serious side effects such as trouble breathing, dizziness, and/or rashes. Call your cancer care team right away if any of these start.
  • The schedule or the way you’re taking the medicine doesn’t work for you.
  • Pain interferes with your normal activities, such as eating, sleeping, working, and sex. To help make the most of your pain control plan:Take your pain medicine on a regular schedule (around the clock) to help control chronic pain. Take it when it’s time to take it – even if you’re not having pain.
  • Do not skip doses of your scheduled medicine. The more pain you have, the harder it is to control.
  • If you have breakthrough pain, use your short-acting medicine as instructed. Don’t wait for the pain to get worse – if you do, it can be harder to control.
  • Be sure only one doctor prescribes your pain medicine. If another doctor changes your medicine, the two doctors should discuss your treatment with each other.
  • Don’t run out of pain medicine. Remember that prescriptions are needed for opioid pain medicines – they can’t be called in and drugstores don’t always have them in stock. It can take a few days to get the medicine, so give yourself time for delays.
  • Store pain medicines safely away from children, pets, and others who might take them.
  • Never take someone else’s medicine. Medicines that helped a friend or relative may not be right for you.
  • Do not use old pain medicine or medicine left over from other problems. Drugs that worked for you in the past may not be right for you now.
  • Pain medicines affect different people in different ways. A very small dose may work for you, while someone else may need to take a much larger dose to get pain relief.
  • Remember, your pain control plan can be changed at any time.
  • Non-opioid pain medicines

Non-opioids control mild to moderate pain. Some can be bought without a prescription. In many cases, non-opioids are all you’ll need to relieve your pain, especially if you “stay on top of the pain” by taking them regularly. These medicines are stronger pain relievers than most people realize.

Table 1. Common non-opioids – Acetaminophen and NSAIDs – and their side effects


Brand-name drugs and generic drugs

Drugs may have as many as 3 different names: brand, generic, and chemical. Drug companies give their products brand names, and some products have more than one brand name. You should also know that the same brand name may be used on different drugs, since the name belongs to the company. Read the labels to see what ingredients are in each medicine.

Chemical names are long and tend to be hard to pronounce. The Food and Drug Administration (FDA) approves the generic, shortened names by which drugs are usually known. Here’s an example:

Brand names: Tylenol, Tempra, Liquiprin, Anacin, Paramol (and many more)
Generic name: acetaminophen
Chemical name: N-(4-hydroxyphenyl) acetamide

Many pain relievers are available under both generic and brand names. We have included some of the more common generic names with their common brand names in parentheses in Table 1. Your doctor, nurse, or pharmacist can tell you the generic and common brand names of any medicines you’re taking. It’s always good to know both because you may hear either name when talking about your medicines. Knowing both names can also keep you from getting confused when keeping track of prescriptions and pill bottles. It can also keep you from taking too much of the same medicine if it’s prescribed using 2 different names.

Generic drugs usually cost less than brand-name ones.

Sometimes medicines can have the same generic name, but are made by different companies. Because the companies may produce the medicines differently, they may differ slightly in the way they’re absorbed by the body. For this reason, your doctor may sometimes prefer that you take a brand-name drug. Ask your doctor, nurse, or pharmacist if you can use a cheaper generic medicine. Pharmacists are careful to get high-quality generic products, so it’s often possible to substitute a generic.
Along with the main substance (for example aspirin, acetaminophen, or ibuprofen), some brands contain substances called additives. Common additives include:

  • Buffers (such as magnesium carbonate or aluminum hydroxide) to decrease stomach upset
  • Caffeine to act as a stimulant and help improve the effect of some pain medicines
  • Antihistamines (such as diphenhydramine or pyrilamine) to help you relax or sleep Medicines with additives can cause side effects you wouldn’t expect from the main drug.

For example, antihistamines sometimes cause drowsiness. This may be all right at bedtime, but it could be a problem during the day. Also, additives tend to increase the cost of non-prescription pain relievers. They can also change the action of other medicines you may be taking or even keep your body from absorbing the other drug. When you start a new drug, even one you can get over the counter, always talk with your doctor or pharmacist about what you’re already taking to see if the combination can cause harmful effects.

Plain aspirin, acetaminophen, or ibuprofen probably works as well as the same medicines with additives. But if you find that a brand with certain additives is a better pain reliever, ask your doctor, nurse, or pharmacist if the additives are safe for you. Talk with them about any concerns you may have about the drugs contained in your non-prescription pain medicines.

Non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) work a lot like aspirin (see list in Table 1). Either alone or used with other medicines, NSAIDs can help control pain. Before you take any NSAIDs or other non-opioids, ask your doctor, pharmacist, or nurse if it’s safe for you to take it with your other medicines, and how long you can take it.

Precautions when taking NSAIDs
Some people are at increased risk of complications related to NSAIDS. In general, NSAIDs should be avoided by people who:

  • Are allergic to aspirin or any other NSAIDs
  • Are on chemotherapy
  • Are taking steroids
  • Are taking blood pressure medicines
  • Have stomach ulcers or a history of ulcers, gout, or bleeding disorders
  • Are taking oral medicine (drugs by mouth) for diabetes or gout
  • Have kidney problems
  • Will have surgery within a week
  • Are taking blood-thinning medicine
  • Are taking lithium

Be careful about mixing NSAIDs with alcohol – taking NSAIDs and drinking alcohol can cause stomach upset and raise the risk of bleeding in the stomach. Smoking may also increase this risk. NSAIDs may also raise your risk of heart attack or stroke, especially if you take them a long time.

Children and teens should not take aspirin or products that contain it.

Side effects of NSAIDs
The most common side effect from NSAIDs is upset stomach, especially in older people. Taking NSAIDs with a snack or just after a meal may lessen your chance of stomach problems. Ask your pharmacist to tell you which NSAID products are less likely to upset your stomach.
NSAIDs also keep platelets from working the way they should. Platelets are the blood cells that help blood clot after an injury. When platelets don’t work like they should, it takes a longer time to stop bleeding. If your stools become darker than normal or if you notice unusual bruising – both signs of bleeding – tell your doctor or nurse.

Other side effects include kidney problems and stomach ulcers. NSAIDs can sometimes cause people to retain fluids and worsen heart failure. They also can affect the actions of other drugs. There are other less common side effects of many NSAIDs that happen in some people.

This medicine relieves pain much the same way NSAIDs do, but it doesn’t reduce inflammation as well as NSAIDs. People rarely have side effects from the usual dose of acetaminophen. But liver and kidney damage may result if you use large doses of this medicine every day for a long time or drink alcohol with the usual dose. Even moderate amounts of alcohol (3 drinks per day) can lead to liver damage in people taking acetaminophen. You also need to be careful about taking other drugs with added acetaminophen. See “Aspirin, acetaminophen, and ibuprofen in other medicines.”

Your doctor may not want you to take acetaminophen regularly if you’re getting chemotherapy because it can cover up a fever. Your doctor needs to know about any fever because it may be a sign of infection, which needs to be treated.

Aspirin, acetaminophen, and ibuprofen in other medicines
Some opioid medicines also contain aspirin or acetaminophen (Tylenol) in the same pill. A few also contain ibuprofen. This can pose dangers for people who take these drugs without knowing about the extra medicine.
If one of your doctors tells you not to take aspirin or ibuprofen, or if you can’t take NSAIDs for some reason, be sure to check your medicine labels carefully.

If one of your prescription medicines has acetaminophen in it, and you also take over-the-counter acetaminophen for pain, you can get too much without knowing it. Too much acetaminophen can damage your liver.
If you’re not sure if a medicine contains aspirin, acetaminophen, or ibuprofen, ask your pharmacist.
If you take any non-prescription medicine for a cold, sinus pain, or menstrual symptoms while you’re taking pain medicines, read the label carefully. Most of these drugs are combination products that contain aspirin, ibuprofen, or acetaminophen. Check with a pharmacist to find out what you can safely take with your pain medicines.

Opioid pain medicines

These medicines are used alone or with non-opioids to treat moderate to severe pain. Opioids are much like natural substances (called endorphins) made by the body to control pain. These medicines were once made from the opium poppy, but today many are synthetic, that is, they’re man-made in a lab.

Common opioids by generic name
Here are some of the opioids used in cancer care. The more common brand names are added in parentheses. An “ER” behind the name of any of these drug names stands for “extended release,” and is a sign that the drug is taken on a regular schedule to treat chronic pain.

  • Codeine*
  • Hydromorphone (Dilaudid)
  • Levorphanol (Levo-Dromoran)
  • Methadone (Dolophine, Methadose)
  • Morphine (Apokyn, Avinza, Kadian, MS-Contin, and others)
  • Oxycodone* (OxyContin, OxyIR, Roxicodone)
  • Hydrocodone*
  • Oxymorphone (Opana)
  • Fentanyl (Duragesic, Actiq, Fentora, Lazanda, and others)

*Common combination opioid and acetaminophen or NSAID drugs:

  • Codeine may be added to aspirin or acetaminophen. For instance, Fiorinal with codeine has aspirin; Fioricet with codeine, Tylenol #3, and Tylenol #4 all contain acetaminophen.
  • Oxycodone may be added to aspirin, acetaminophen, or ibuprofen. For instance, Percodan has aspirin in it; Percocet, Roxicet, Roxilox, Oxycet, and Tylox all have acetaminophen; Combunox has ibuprofen.
  • Hydrocodone may be added to acetaminophen or ibuprofen. For instance, Zydone, Norco, and Lortab all contain acetaminophen; Vicoprofen and Reprexain have ibuprofen.

Opioid tolerance

People who take opioids for pain sometimes find that over time they need to take larger doses. This may be due to an increase in the pain or the development of drug tolerance. Drug tolerance is when your body gets used to the opioid you’re taking, and it takes more medicine to relieve the pain as well as it once did. Many people do not develop a tolerance to opioids. But if tolerance does develop, usually small increases in the dose or a change in the kind of medicine will help relieve the pain.

Increasing the doses of opioids to relieve increasing pain or to overcome drug tolerance does NOT mean that a person is addicted.

How to get proper pain relief with opioids
When a medicine doesn’t give you the pain relief you need, your doctor may prescribe a higher dose or tell you to take it more often. When your cancer care team is working closely with you, doses of strong opioids can be raised safely to ease severe pain. Do not increase the dose of yourpain medicine on your own. If dose changes don’t work, your doctor may prescribe a different drug or add a new drug to the one you’re taking.

If your pain relief isn’t lasting long enough, ask your doctor about extended-release medicines that come in pills and patches. These can control your pain for a longer period of time.

If your pain is controlled most of the time, but you sometimes have breakthrough pain, your doctor may prescribe a fast-acting medicine or immediate-release opioid that will give you faster pain relief right when it’s needed.

Be safe when taking opioids.
Doctors carefully watch you and adjust the doses of pain medicine so you don’t take too much. For this reason, it’s important that only one doctor prescribe your pain medicines. If you’re working with 2 or more doctors, be sure that one does not prescribe opioids for you without talking to the others about it.

If you drink alcohol or take tranquilizers, sleeping pills, antidepressants, antihistamines, or any other medicines that make you sleepy, tell your doctor how much and how often you do this.

Combinations of opioids with alcohol or tranquilizers can be dangerous. Even small doses may cause problems. Using such combinations can lead to overdoses and symptoms such as weakness, trouble breathing, confusion, anxiety, or more severe drowsiness or dizziness.

Side effects of opioids

Not everyone has side effects from opioids. The most common side effects are usually drowsiness, constipation, nausea, and vomiting. Some people might also have dizziness, itching, mental effects (such as nightmares, confusion, and hallucinations), slow or shallow breathing, or trouble passing urine.

Many side effects from opioid pain medicine can be prevented. Some of the mild ones such as nausea, itching, or drowsiness, often go away without treatment after a few days, as your body adjusts to the medicine. Let your cancer care team know if you’re having any side effects and ask for help in managing them.

Here are a few of the more common side effects:

When you first start taking them, opioids may cause drowsiness, but this usually goes away after a few days. If your pain has kept you from sleeping, you may sleep more for a few days after starting opioids while you “catch up” on your sleep. Drowsiness will also lessen as your body gets used to the medicine. Call your cancer care team if you still feel too sleepy for your normal activities after you’ve been taking the medicine for a week.

Sometimes it may be unsafe for you to drive a car, or even to walk up and down stairs alone. Do not do anything that requires you to be alert until you know how the medicine affects you.

Here are some ways to handle drowsiness:
Wait a few days and see if it goes away.

  • Check to see if other medicines you’re taking can also cause drowsiness.
  • Ask the doctor if you can take a smaller dose more often or an extended-release opioid.
  • If the opioid is not relieving the pain, the pain itself may be tiring you out. In this case, better pain relief may lead to less drowsiness. Ask your cancer care team what you can do to get better pain relief.
  • Sometimes a small decrease in the dose of an opioid will still relieve your pain without causing drowsiness. If the drowsiness is very bad, you may be taking more medicine than you need. Talk to your doctor about lowering the amount you’re taking.
  • Ask your doctor about changing to a different medicine.
  • Ask your doctor if you can take a mild stimulant such as caffeine during the day.
  • If drowsiness is bad or if it suddenly starts to be a problem after you’ve been taking opioids for a while, call your cancer care team right away.

Opioids cause constipation in most people. This is because opioids slow the movement of stool through the intestinal tract, which allows more time for water to be absorbed by the body. The stool then becomes hard. It’s best to start a laxative, stool softener, or other treatment to keep your bowels moving when you start taking opioids. Constipation can often be prevented or controlled.

After checking with your cancer care team, try the following to prevent constipation:

  • Talk with your team about stool softeners and laxatives. Ask how often and how much you should take.
  • Drink plenty of liquids. Eight to 10 8-ounce glasses of fluid each day can help keep your stools soft. This is a very important step – if your stool is dry, it will be hard to pass.
  • Eat foods high in fiber or roughage such as uncooked fruits (with the skin on), vegetables, and 100% whole-grain breads and cereals.
  • Add 1 or 2 tablespoons of unprocessed bran to your food. This adds bulk and promotes bowel movements. Keep a shaker of bran handy at mealtimes to make it easy to sprinkle on foods. Be sure to drink plenty of water when you eat bran so that it softens in the bowel.
  • Exercise as much as you can. Talk with your doctor about what kind of exercise is best for you. Walking is often a good start if you haven’t exercised recently.
  • Eat foods that have helped you relieve constipation in the past.
  • If you haven’t been getting out of bed, try to use the toilet or bedside commode when you have a bowel movement, even if that’s the only time you get out of bed.

If you’re still constipated after trying all the above measures, ask your doctor about changing your stool softener or laxative. Check with your cancer care team before taking any laxative or stool softener on your own. If you haven’t had a bowel movement for 2 days or more, call your team.

Nausea and vomiting
Nausea and vomiting caused by opioids will usually go away after a few days of taking the medicine. These tips may help:

  • If you have more nausea when you’re up or walking around but not when you’re lying down, stay in bed for an hour or so after you take your pain medicine. This type of nausea is like motion sickness. Sometimes over-the-counter medicines such as meclizine (Bonine or Antivert) or dimenhydrinate (Dramamine) help this type of nausea. Check with your cancer care team before taking these medicines, since they can cause problems for some people.
  • If pain itself is causing the nausea, using opioids to relieve the pain usually makes the nausea go away.
  • Medicines that relieve nausea can be prescribed if you need them. Talk with your cancer care team if you can’t hold down foods or liquids for a full day, or if nausea lasts more than a few days.
  • Ask your team if the cancer, another medical problem, steroids, chemo, or other medicines might be causing your nausea. Constipation may also worsen nausea.

Some people think they’re allergic if they have nausea after they take an opioid. Nausea and vomiting alone usually are not allergic reactions. But a rash or itching along with nausea and vomiting may be an allergic reaction. If this happens, stop taking the medicine and call your cancer care team right away. If you have swelling in your throat, hives (itchy welts on the skin), and/or trouble breathing, get help right away.

When you no longer need opioids
You should not suddenly stop taking opioids. People who stop taking opioids are usually tapered off the medicine slowly so that their bodies have time to adjust. If you stop taking opioids suddenly and develop a flu-like illness, excessive sweating, diarrhea, or any other unusual reaction, tell your cancer care team. These symptoms can be treated and tend to go away in a few days to a few weeks. Again, slowly decreasing your opioid dose over time usually keeps these kinds of symptoms from happening. Check with your doctor about the best dose schedule for tapering off your pain medicines.

Other types of pain medicine
Many different types of medicines can be used along with (or instead of) opioids to help relieve cancer pain. Some of these medicines relieve pain or increase the effect of opioids. Others lessen the side effects of opioids. These drugs are often started at low doses and increased over time.

Table 2 shows the classes and some examples of non-opioid drugs that might be used to help you get the best pain relief with as few side effects as possible.

Table 2. Other medicines commonly used to relieve cancer pain


Other medical methods to relieve pain

Some people have pain that’s not relieved by drugs or non-medical methods. When this happens, other treatments can often be used to help reduce pain.

Stopping pain impulses from going through the nerves

Pain can’t be felt if the nerve pathways that carry pain impulses or signals to the brain are interrupted. To block these pathways, a neurosurgeon may cut nerves, usually near the spinal cord. When the nerves that relay pain are cut, feelings of pain, pressure, and temperature can no longer be felt – the area becomes numb. Only surgeons with special skills, who are also experts in pain management, should do this kind of surgery. These surgeons normally work with other pain specialists to explore other methods of pain control before they cut nerves – this treatment can’t be reversed.

Nerve block
A nerve block is a procedure where a local anesthetic (a numbing drug), often combined with a steroid, is injected into or around a nerve or into the space around the spinal cord to block pain. After the injection, the nerve is no longer able to relay pain so the pain is relieved for some time. For longer-lasting pain relief, phenol or alcohol can be injected. A nerve block may cause muscle paralysis or a loss of all feeling in the affected area.

Spinal analgesia
Low doses of pain medicine may be injected into the fluid around the spine (called intrathecal injection). If this works, a tube and a pump may be used to deliver the pain medicine right into the spinal fluid to control the pain. Morphine is often used for this purpose, and you can still have side effects like itching and constipation. Surgery is done to put the small pump and tube into your body.

Certain kinds of pain may respond to pain medicine that’s injected into the space around the layers of the spine. If this works, a pump can be implanted so that you can get pain medicines right around the nerves. This may cause numbness or weakness of the treated area.

More cancer treatment may be given to shrink the tumor.
Sometimes, even when cancer treatment can’t cure the cancer, it can shrink the size of a tumor that’s pressing on nerves and organs and causing pain. Chemo, hormone therapy, or radiation may be used in this way. Radioactive injections are sometimes used when the cancer has spread to many places in the bone – the radioactive drug settles in the bones near the cancer and helps to stop its growth and relieve pain. In a few cases, other treatments like radiofrequency ablation can be used in certain areas of the body. In this treatment, electrodes are put in near the tumor to heat and destroy the cancer.

Source: http://www.cancer.org/treatment/treatmentsandsideeffects/physicalsideeffects/pain/paindiary/pain-control-toc