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Medicines for managing pain

Pain medicines can help manage different types and levels of pain. Talk to the healthcare team about any pain as soon as possible. Pain may be harder to control and it may take longer for the medicines to work if they aren’t taken as soon as pain starts. Different pain medicines are often used at the same time.

Stepped approach to managing pain

Doctors often use the World Health Organization’s stepped approach to manage pain. It is based on how severe the pain is and how someone responds to pain medicines. Weaker pain-relieving medicines, usually non-opioid drugs, are given first. If these drugs do not manage the pain, stronger medicines are given. These stronger medicines are usually opioid drugs. Someone with medium (moderate) to very bad (severe) pain may be given stronger pain-relieving medicines right away.

Different medicines work better for different types or causes of pain. It may take a few weeks to find the right drug and dose to control pain with the fewest side effects.


Mild pain is treated with non-opioid drugs. An example of a drug used to control mild pain is acetaminophen (Tylenol, Atasol).


Mild to moderate pain is treated using a weak opioid drug (such as codeine), often combined with a non-opioid (such as acetaminophen).


Moderate to severe pain is treated with stronger opioids. Examples of drugs used to control moderate to severe pain include morphine (MS Contin, Statex, MOS), fentanyl (Duragesic), hydromorphone (Dilaudid), oxycodone (OxyContin) or codeine. They may be combined with a non-opioid.


Breakthrough pain is treated with fast-acting opioids that are often given by mouth. Examples include oral morphine or fentanyl in a lozenge or sucker form.


Nerve pain includes tingling or burning pain. It is treated with antidepressants or anticonvulsants. Examples of antidepressants include amitriptyline (Elavil), nortriptyline (Aventyl) and desipramine. Examples of anticonvulsants include carbamazepine (Tegretol), gabapentin (Neurontin) and phenytoin (Dilantin).


Pain caused by swelling or pressure is treated with steroids, such as prednisone (Deltasone)or dexamethasone (Decadron, Dexasone).

Pain medicines usually need to be taken on a regular schedule. Some drugs are short-acting (immediate release). These drugs may be used for acute pain. They start to relieve pain fairly quickly, but for a shorter period of time (2–4 hours). Other drugs are long-acting (sustained or controlled release). Their dose is delivered over a longer period of time, often over 12 hours or more. These drugs are often used for chronic or constant pain.

Doctors often order a combination of short-acting and long-acting drugs. A short-acting drug may be prescribed to control any breakthrough pain felt between the scheduled doses of a long-acting drug. The amount of time between doses can vary depending on the specific drug and how well the drug is working. If several doses of drugs are needed to control breakthrough pain, the dose of the long-acting medicine may be increased.

Doses may be lowered or stopped altogether when cancer treatments, such as radiation therapy or surgery, relieve the pain. Pain medicine should not be stopped suddenly. The doctor will slowly lower the dose of pain medicine over time, until it is low enough to be stopped completely. The dose may also be lowered when the pain is controlled but the drug is causing drowsiness (sedation).

How pain medicines are given

Pain medicines can be given in many different ways. How they are given depends on what works best for a situation and whether or not the drugstore or pharmacy has a specific form of a drug.

Oral medicines

The most common way of taking pain medicine is by mouth (orally). Wherever possible, oral medicines are in the form of a pill, tablet, capsule or liquid. Some pills, tablets and capsules are made with a special coating so they release their active ingredient slowly over many hours. These are called sustained-release or controlled-release drugs. Talk to your doctor or pharmacist about how to take your medicines and be sure to follow the instructions. Most sustained-release forms of pain-relieving drugs shouldn’t be crushed or chewed. Some pain medicines don’t have to be swallowed. They may be placed under the tongue (sublingual) or given as a lozenge that you suck on. These drugs are absorbed through the inside of the mouth.

If someone has a feeding tube in place, painkillers that are liquid or that dissolve (are soluble) can be given directly into the stomach through the tube.

Topical medicines

Some medicines may be applied to the skin as a cream, gel or ointment. These drugs are called topical or transdermal. They move through the skin into the bloodstream. They are used for some types of pain on the surface of the body.

Sometimes a patch is used to deliver a constant amount (dose) of pain-relieving medicine. It may take a day or longer for medicines given in this way to relieve or control the pain, so breakthrough doses of medicine may also be given.

Topical anesthetics numb the skin and make it feel frozen. They can be used to ease pain from damaged nerves near the surface of the body. For example, a mixture of lidocaine and prilocaine (EMLA cream) may be used as a topical anesthetic to numb the skin before a needle stick or before minor surgical or diagnostic procedures.

Topical nonsteroidal anti-inflammatory drugs (NSAIDs) may relieve the pain of swollen joints.


Injections are given through needles. When a medicine is injected, the body absorbs and uses it quickly. Pain medicines may be given by injection if there is difficulty swallowing or when pain needs to be relieved or controlled right away. There are many ways to inject medicines into the body.

Subcutaneous injections put medicine into the fatty tissue just below the skin. If many subcutaneous injections will need to be done, a tiny metal needle may be placed just under the skin and left there for several days to avoid repeated needle sticks.

Intravenous injections are given through a small needle or tube (catheter) placed in a vein. These can be left in place for several days to avoid repeated needle sticks.

Epidural or intrathecal injections are given through a needle or catheter placed in the space next to the spine. This type of injection is usually only used after some surgeries. It may also be used if someone continues to have moderate or severe pain or severe side effects with other methods of pain relief. The catheter is often placed under the skin. This helps for repeated injections and it also lowers the risk of infection or that the catheter will move out of place.

Pain pumps

Sometimes it is necessary to have a constant level of pain medicine in the body. A continuous pump is also called an infusion device. It may be used to make sure that a constant dose of medicine is given. These pumps are outside of the body. They are usually attached to a subcutaneous or intravenous needle, but they may also be attached to a spinal catheter in some cases. Some pumps are small and portable so they can be used at home.

Taking pain medicines as directed

It is very important to take pain medicines as directed by the healthcare team. Following their directions will help keep the level of medicines constant and make sure that pain is controlled. The healthcare team’s instructions for taking pain medicines usually include directions for when to take drugs, such as the following.

PRN means as needed. When a drug is given PRN, it is given only when there is pain.

Around the clock (ATC) means that the drug is given at specified times within a 24-hour period, whether there is pain or not. This can prevent pain before it starts.

Patient-controlled analgesia (PCA) allows a patient to control when and how much pain medicine they receive (within safe limits). With PCA, a button is pushed to start a pump that releases a controlled amount of pain medicine through an intravenous line. There is a limit to how much of the drug can be given over a certain amount of time. Once that limit is reached no more medicine is released. The PCA pump can also be programmed to give a small amount of pain medicine continuously. The button can be pushed for an extra dose of medicine if needed.

Talk to the healthcare team about stopping a pain medicine for any reason. Don’t just stop taking the medicine. A sudden change in the level of drug in the body may cause unpleasant side effects. Talk to the healthcare team about any concerns about a drug or any side effects it may be causing. There may be other options for managing pain.

Keeping a record of pain and medicines

It may take a few days to figure out the right amount of medicine and how it needs to be taken to ease or control pain. It may help to keep a record of the pain medicines taken, how often they are taken and how well they control pain. This will help the healthcare team determine the best way to manage pain.

The dose taken should be enough to control pain until the next dose. Tell the healthcare team if pain returns before the next dose. Sometimes pain will get worse at certain times of the day or with certain activities. The pain may “break through”the relief given by the regular doses. When this happens, an extra (breakthrough) dose of medicine or a different drug may be given to deal with this type of pain.

Some drugs do not work well together. Tell the healthcare team about any other medicines being used, including:

  • prescription drugs
  • over-the-counter drugs
  • vitamin or mineral supplements
  • herbal remedies and other natural health products
  • complementary or alternative therapies

Concerns about pain medicines

Pain is almost always manageable. But some people may not want to take pain medicines because they are scared of side effects, addiction or losing control. Some people also hold certain beliefs about pain medicines that make them worry about taking these drugs.

Side effects

Some pain medicines can cause side effects. Some of these side effects may go away after you take the drugs for a period of time. Other side effects might not go away. The healthcare team can help with managing side effects by changing the medicine or dose or by treating the side effect.


Many people fear that taking pain medicines can lead to addiction. Taking pain medicine regularly is very different from addiction. A key part of addiction is a mental dependence on the drug. This happens when the need to take a drug becomes a craving or an impulse that is more than just physical. Addiction to drugs used to treat cancer pain is rare.

The body can get used to some drugs if they are taken for a long period of time. This is called physical dependence and it is a normal physical response. When it’s time to stop taking pain medicines such as opioids the healthcare team will slowly lower the dose so that the body has time to adjust.

Losing control

Some people may worry about losing control, getting a mental high or not being aware of what’s going on if taking pain medicines. When prescribed painkillers are taken properly, they don’t cause a mental high or loss of control. Pain medicines can cause drowsiness at first. This side effect is not part of addiction or psychological dependence, and it usually goes away within a few days. The healthcare team will make sure that the dose of the pain medicine is just enough to keep the pain under control. Sometimes adjusting the dose or changing the type of painkiller can help lessen drowsiness or changes in mental awareness.

Not knowing if treatment is working

Some people believe that fighting cancer involves feeling pain. They may worry that when taking pain medicines they will not know if the cancer is responding to treatment or if it is progressing. It is important to know that pain isn’t a necessary part of having cancer. The healthcare team will be able to tell in other ways if the treatment is working. Taking pain medicines will not affect treatment.

When pain is controlled, it is easier to cope with treatment and quality of life will also be better. Pain is easier to control if it is treated quickly. The best way to control pain is to prevent it or keep it from getting worse. Long-term pain can permanently affect the body and the brain so that the body becomes more sensitive to pain.

Believing that pain medicines will not work when needed

Sometimes the body will get used to a drug so that a higher dose is needed for it to work. This is known as drug tolerance. When someone develops a tolerance to a pain medicine, they may worry that it will not work when they really need it. Drug tolerance usually doesn’t happen with medicines used to treat cancer pain. If it does, the healthcare team can adjust the dose slightly or prescribe a different type of medicine.

Believing that pain medicines will shorten life

Some people think that using an opioid like morphine will shorten their life. This is not true. Using opioids regularly to control pain doesn’t damage internal organs or cause permanent side effects. In many cases, these stronger drugs are needed to control pain, and they can be used for a long time. In fact, there is some evidence that people whose pain is better controlled live longer.

Questions to ask about pain medicines

It is natural to have questions about pain medicines. Finding the right answers to any questions is important and can help in making decisions.

Ask the healthcare team any questions you have about pain medicines, including:

  • How much medicine should I take? How often should I take it?
  • If my pain doesn’t go away, can I take more medicine? How much more should I take?
  • When should I call the doctor? Should I call before taking more medicine?
  • How long does the medicine last?
  • What if I forget to take my medicine or take it later than I was supposed to?
  • Should I take my medicine with food?
  • How much liquid should I drink with my medicine?
  • How long does it take for the medicine to work?
  • Is it safe to drive when taking this medicine?
  • Are there any drugs that I need to avoid while taking this pain medicine? Is it safe to drink alcohol when taking it?
  • What other medicines can I use with this pain medicine?
  • Does this drug cause any side effects? What can I do to prevent or cope with side effects?


Dr Edward Chow A new standard for managing cancer pain

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