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Understanding cancer pain


Managing pain with medicines


Medicines used to control mild cancer pain include paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs). They are often available over the counter from pharmacies without a prescription.

These types of drugs can help relieve certain types of pain, such as bone pain, muscle pain, and pain in the skin or in the lining of the mouth. NSAIDs can reduce inflammation or swelling, and be used with stronger pain medicines such as opioids, to help relieve moderate to severe pain.

Paracetamol

Paracetamol is a common drug that is known by various brand names such as Panadol and Panamax. It comes in many different formulations. An adult should take no more than 4 g of paracetamol in 24 hours (usually 8 tablets), unless your doctor says it’s safe to do so. For some people, a lower dose of paracetamol is recommended due to low body weight or liver problems.

The maximum dose for children depends on their age and weight, so check with the doctor, nurse or pharmacist.

If taken within the recommended dose, paracetamol is unlikely to cause side effects. Some stronger pain medicines contain paracetamol along with another drug, and count towards your daily total intake. Taking too much of one type of medicine may lead to an overdose.

If you are unsure whether a medicine contains paracetamol, check with your doctor, nurse or pharmacist. In some cases, your doctor will recommend you take paracetamol with other stronger pain medicines, such as oxycodone, to help them work better.

Non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are a group of medicines that include ibuprofen, naproxen, celecoxib, diclofenac and aspirin. They are known by various brand names, such as Advil and Nurofen. You can have these medicines as tablets or sometimes as injections. Less commonly, NSAIDs are given as a suppository.

Do not take more than one NSAID medicine at the same time – if you’re unsure, check with your doctor, nurse or pharmacist. 

Side effects of NSAIDs 

Before taking NSAIDs, ask your doctor if they are suitable for you, as some people are at higher risk of side effects. Common side effects include nausea and indigestion. Rare side effects include a risk of bleeding in the stomach or intestines, and kidney problems.

Some studies show that NSAIDs can cause heart problems, especially if used for a long time or in people who have heart problems. Talk to your doctor or nurse before taking NSAIDs, especially if you have stomach ulcers, heart disease, kidney disease or gut reflux, are having chemotherapy, or are taking other medicines that also increase your risk of bleeding (such as anticoagulants/blood thinners).

If you are taking NSAIDs in high doses or for a long time, take them with food to lower the risk of indigestion. You can also ask about using a different type of pain medicine that is less likely to cause indigestion and bleeding, such as paracetamol.

 

Opioids

Opioids are medicines made from the opium poppy or created in a laboratory. They block pain messages between the brain and spinal cord and the body. Opioids can be used to reduce some types of pain, such as acute pain and chronic cancer pain.

There are different types of opioids and they come in varying strengths. The type you have depends on:

  • what kind of pain you have
  • how much pain you are in
  • whether you can take oral (by mouth) medicines
  • other factors such as how well your kidney and liver work.

You can only have these drugs by prescription from your doctor. Codeine is an opioid that used to be commonly used for mild to moderate cancer pain. It is now only available by prescription and not often used.

Sometimes using opioids can cause more pain. This is called opioid-induced hyperalgesia. It happens because taking opioids for a long time makes specific nerves and the brain more sensitive to pain.

Working out the dose 

As people respond differently to opioids, the dose is worked out for each person based on their pain level. It’s common to start at a low dose and build up gradually to a dose that controls your pain. Sometimes this can be done more quickly in hospital or under strict medical supervision. Some people do not respond to opioids. 

You may be prescribed a combination of slow release and immediate release drugs. You may have immediate release to deal with breakthrough pain.

Side effects of opioids

Opioids can affect people in different ways, but you may have some of the following common side effects: 

  • Constipation – opioids slow down the muscle contractions that move food through your colon, which can cause hard faeces (stools or poo). To keep stools soft, your treatment team will suggest you take a laxative at the same time as the opioid medicines. Drinking 6–8 glasses of water a day, eating a high-fibre diet and getting some exercise can all help manage constipation, but this may be difficult if you’re not feeling well.
  • Feeling sick (nausea) – this usually improves when you get used to the dose, or can be relieved with other medicines. Sometimes you may need to try a different opioid.
  • Drowsiness – feeling sleepy is typical when you first start taking opioids, but usually improves once you are used to the dose. Tell your doctor or nurse if you continue to feel drowsy as you may need to adjust the dose or change medicines. Alcohol can make drowsiness worse and is best avoided. Opioids can affect your ability to drive.
  • Dry mouth – opioids can reduce the amount of saliva in your mouth, which can cause tooth decay or other problems. Chewing gum or drinking plenty of liquids can help. Visit your dentist regularly to check your teeth and gums.
  • Tiredness – your body may feel physically tired, so you may need to ask family or friends to help you with household tasks or your other responsibilities. Research shows that stretching or a short walk helps you maintain a level of independence and can give you some energy.
  • Itchy skin – if you have itchy skin, sometimes it may feel so irritated that it is painful. A moisturiser may help, or ask your doctor if there is an anti-itch medicine or a different opioid you can try.
  • Poor appetite – you may not feel like eating. Small, frequent meals or snacks and supplement drinks may help. If the loss of appetite is ongoing, see a dietitian for further suggestions.
  • Breathing problems – opioids can slow your breathing. This usually improves as your body gets used to the dose. To help your body adapt to how opioids affect your breathing, you will usually start on a low dose and gradually increase the amount. Your doctor may advise you not to drink alcohol or take sleeping tablets while you are on opioids.
  • Hallucinations (seeing or hearing things that aren’t there) – this is rare. It is important to tell your doctor immediately if this occurs.

Your health care team will closely monitor you while you’re using opioids. Let them know about any side effects you have. They will change the medicine if necessary.

Signs of withdrawal

If you stop taking opioids suddenly, you will usually have withdrawal symptoms or a withdrawal response. This is because your body has become used to the dose (physical dependence). Withdrawal symptoms may include:

  • agitation
  • nausea
  • abdominal cramping
  • diarrhoea
  • heart palpitations
  • sweating.

To avoid withdrawal symptoms, your doctor will reduce your dose gradually to allow your body to adjust to the change in medicine. Don’t reduce your dose or stop taking opioids without talking to your doctor first. They will develop a plan to gradually reduce the dose.

 

Common questions about opioids

Most people have questions about taking opioid medicines. Your doctor, nurse practitioner or nurse can discuss any concerns you have. Some common questions include:

Will I become addicted to opioids?

One reason that some people don’t use opioids is because they worry about becoming addicted to opioids.

When people take morphine or other opioids to relieve acute pain or for palliative care, they may experience withdrawal symptoms when they stop taking a drug, but this is not addiction. A person with a drug addiction problem takes drugs to fulfil physical or emotional needs, despite the drugs causing harm.

Some people who take opioids long term for pain relief are at risk of becoming addicted. The risk is higher for people who have a history of misusing opioids or other medicines before their cancer diagnosis. People who use opioids to manage chronic pain over a long period of time are also at risk of becoming addicted.

Talk to your doctor if you are concerned about drug dependence.

Will I need to have injections?

Not usually. Strong pain medicines are usually given by mouth as either a liquid or tablet, and work just as well given this way as injection. If you’re vomiting, opioids can be given as a suppository inserted into the bottom, by a small injection under the skin (subcutaneously), through a skin patch or in sublingual tablet form.

Opioids can also be injected into a vein for short-term pain relief, such as after surgery. This is called intravenous opioid treatment, and it is given in hospital.

If I start opioids now, will they still work well later? 

Some people try to avoid taking pain medicine until the pain is severe, thinking it is better to hold out for as long as possible so the medicine works better later. However, this may change the way the central nervous system processes the pain, causing people to experience pain long after the cause of the pain is gone.

It is better to take medicine as prescribed, rather than just at the time you feel the pain.

If I’m given opioids, does that mean the cancer is advanced?

People with cancer at any stage can develop severe pain that needs to be managed with strong opioids, such as morphine. Opioids are also commonly prescribed after surgery.

Being prescribed opioids doesn’t mean you will always need to take them. If your pain improves, you may be able to take a milder pain medicine or try other ways to manage the pain, or you may be able to stop taking strong pain medicines.

What if I get breakthrough pain?

While it’s relatively common for people diagnosed with cancer to get breakthrough pain, this sudden flare-up of pain can be distressing. You might get breakthrough pain even though you’re taking regular doses of medicine. The pain may happen on occasion or as often as several times a day. This breakthrough pain may last only a few seconds, several minutes or hours.

Causes of breakthrough pain may vary. It can occur if you have been more active than usual or have strained yourself. Other causes of breakthrough pain include anxiety, or illnesses such as a cold or urinary tract infection. Sometimes there seems to be no reason for the extra pain.

Talk to your treatment team about how to manage breakthrough pain. They may prescribe an extra, or top-up, dose of a short-acting (immediate release) opioid to treat the breakthrough pain. The dose works fairly quickly, in about 30 minutes.

It is helpful to make a note of when the pain starts, what causes it and how many extra doses you need. This information will help your doctor better understand your pain experience. If you find your pain increases with some activities, taking an extra dose of medicine beforehand may help.

Will my body get used to the opioids? 

Some people with cancer stop getting pain relief from their usual opioid dose if they use it for a long time. This is known as tolerance. This means that the body has become used to the dose and your doctor will need to increase the dose or give you a different opioid to achieve the same level of pain control. You can develop tolerance without being addicted.

Can I drive while using opioids? 

All drugs that affect the central nervous system can affect the skills needed for driving such as reaction times, alertness and decision-making. Doctors have a duty to advise patients not to drive if they are at risk of causing an accident that may harm themselves or others.

While taking opioids, particularly during the first days of treatment, you may feel drowsy and find it hard to concentrate, so driving is not recommended. Before you drive, ask your doctor for advice and consider the following:

  • Don’t drive if you’re tired, you’ve been drinking alcohol, you’re taking other medicine that makes you sleepy, or road conditions are bad.
  • It is against the law to drive if your ability to drive safely is influenced by a drug. Also, if you have a car accident while under the influence of a drug, your insurance company may not pay out a claim.
  • Once the dose is stabilised, take care driving. Keep in mind that changes in dose or stopping opioids suddenly can affect driving, as can using breakthrough pain medicine.
  • Special rules and restrictions about driving apply to people with brain tumours, including secondary brain cancer, or people who have had seizures.
  • For more information, talk to your doctor or read Assessing Fitness to Drive from Austroads. 

Can I stop taking opioids at any time?

Stopping opioids suddenly can cause side effects. You should only reduce your dose or stop taking opioids after talking with your health care team. They will develop a withdrawal plan (called a taper) to gradually reduce the amount of medicine you take. It may take a few weeks to safely reduce the dose.

Other medicines

To help manage pain, your doctor may prescribe medicines that are normally used for other conditions. For example, antidepressant, anticonvulsant, anti-anxiety or steroid medicines. These can work well for some types of chronic pain, particularly pain caused by nerve damage.

These medicines can be used on their own or with opioids at any stage of the cancer diagnosis and treatment. When prescribed with opioids, these drugs are known as adjuvant drugs or adjuvant analgesics. They can increase the effect of the pain medicine.

Adjuvant drugs are usually given as a tablet that you swallow. Some drugs don’t work right away, so it may take a few days or weeks before they provide relief. In the meantime, opioids are used to control the pain. If you are taking an adjuvant drug, it may be possible for your doctor to reduce the dose of the opioids. This may mean that you experience fewer side effects without losing control of the pain.

Your doctor will talk to you about any potential side effects before you start taking a new medicine.

Medicinal use of cannabis

Medicinal cannabis refers to a range of prescribed products that contain the two main active ingredients, delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC and CBD are cannabinoids. Other types of cannabinoids include cannabis, which is also known as marijuana, weed and pot. Cannabinoids are chemicals that act on certain receptors found on cells in our body, including cells in the central nervous system.

There is no evidence that medicinal cannabis can treat cancer. There is some evidence that cannabinoids can help people who have found conventional treatment unsuccessful for some symptoms and side effects. To date, published studies have shown medicinal cannabis to have little effect on appetite, weight, pain or sleep problems.

The International Association for the Study of Pain does not endorse the use of medicinal cannabis for pain. Research is continuing in this area. Cannabis is an illegal substance in Australia. However, the Australian Government allows seriously ill people to access medicinal cannabis for medical reasons. The Therapeutic Goods Administration’s Special Access Scheme allows eligible medical practitioners to apply to import and supply medicinal cannabis products.

The laws about access to medicinal cannabis vary between states and territories. These may affect whether you can be prescribed this substance where you live.

 

Understanding Cancer Pain

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Expert content reviewers:

Dr Tim Hucker, Pain Medicine Specialist, Peter MacCallum Cancer Centre, VIC; Dr Keiron Bradley, Palliative Care Consultant, Bethesda Health Care, WA; A/Prof Anne Burke, Co-Director Psychology, Central Adelaide Local Health Network, President, Australian Pain Society, Statewide Chronic Pain Clinical Network, SA, School of Psychology, The University of Adelaide, SA; Tumelo Dube, Accredited Pain Physiotherapist, Michael J Cousins Pain Management and Research Centre, Royal North Shore Hospital, NSW; Prof Paul Glare, Chair in Pain Medicine, Palliative Medicine Specialist, Pain Management Research Institute, The University of Sydney, NSW; Andrew Greig, Consumer; Annette Lindley, Consumer; Prof Melanie Lovell, Palliative Care Specialist HammondCare, Sydney Medical School and The University of Technology Sydney, NSW; Caitriona Nienaber, 13 11 20 Consultant, Cancer Council WA; Melanie Proper, Pain Management Specialist Nurse Practitioner, Royal Brisbane and Women’s Hospital, QLD; Dr Alison White, Palliative Medicine Specialist and Director of Hospice and Palliative Care Services, St John of God Health Care, WA.

Page last updated:

The information on this webpage was adapted from Understanding Cancer Pain - A guide for people with cancer, their families and friends (2021 edition). This webpage was last updated in May 2022.

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