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Overcoming cancer pain

Treating moderate to severe pain

Saturday 1 September, 2018

Opioids are commonly used when pain is hard to ignore or feels very severe. These drugs need to be prescribed by a doctor. Opioids are not effective for all types of pain. For instance, moderate to severe nerve pain is treated with other types of medicine.


Opioids are medicines obtained from the opium poppy or created in a laboratory. They work on opioid receptors in the brain and spinal cord to reduce pain. There are many different types of opioids.

Codeine is often used for short periods to manage moderate pain. It is not recommended for long-term or palliative use because it causes constipation. In most cases, codeine is broken down in the body into morphine. However, one in ten people find they don't get any pain relief as they cannot convert codeine into morphine.

Codeine is often available in combination with other pain medicines, such as paracetamol (e.g. Panadeine Forte) or ibuprofen (e.g Nurofen Plus). If taking one of these stronger combination pain medicines does not offer more relief, let your doctor know as you may need other opioids or a different type of analgesic.

Strong opioids, such as morphine, oxycodone, hydromorphone, methadone and fentanyl, are often effective for moderate to severe pain, and can be used safely if taken as prescribed. Commonly used opioids are listed in the table below. They either release the opioid slowly to control your pain for long periods, or release it quickly to control pain for short periods.

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 until the pain is well controlled. Sometimes this can be done more quickly in hospital or under strict medical supervision.

Opioids commonly used for moderate to severe pain

Slow release (long-acting)
Generic name
Brand name
  • Durogesic
  • Jurnista
  • MS Contin
  • Kapanol
  • MS Mono
  • OxyContin
  • Targin
  • Tramal SR
  • Durotram XR
  • Zydol SR
  • Palexia SR


Immediate release (short-acting)
Generic name
Brand name
  • Anamorph
  • Ordine
  • Sevredol
  • Endone
  • OxyNorm
  • Proladone
  • Dilaudid
  • Actiq
  • Tramal

Side effects of opioids

Opioids can affect people in various ways. It can take a few days to adjust to taking strong pain medicines. You may have some of the following side effects:

Breathing problems

Opioids can cause breathing problems. To help your body adapt to the effects of opioids on 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.


Most people who regularly take opioid medicines experience difficulty passing bowel motions (constipation). Your treatment team will suggest or prescribe a suitable laxative to take at the same time as the pain medicines. You may also be given a stool softener. Other ways to help manage constipation include drinking 6-8 glasses of water a day, eating a high-fibre diet and getting some exercise, but these things may be difficult if you're not feeling well.

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.


Feeling sleepy is typical, but this usually lasts for only a few days until the pain medicine dose is stable. Tell your doctor or nurse if it lasts longer as you may have to change medicines. Alcohol is likely to increase drowsiness and is best avoided. Your doctor may advise you not to drive - see concerns about driving.


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. Rest is important, but it's also beneficial to do some light exercise, such as stretches or a short walk. This helps you maintain a level of independence and can give you some energy.

Feeling sick (nausea)

This usually passes when you get used to the dose, or can be relieved with other medicines. Sometimes a change in the type of opioid is necessary.

Itchy skin

If you have itchy skin, sometimes it may feel so irritating that it is painful. A moisturiser may help, or ask your doctor if there is an anti-itch medicine available or if you can try a different opioid for your pain.

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.

Confusion or hallucinations

This is rare. It is important to tell your doctor immediately if this occurs.

Physical dependence

If you stop taking opioids suddenly, you will usually have withdrawal symptoms or a withdrawal response. This may include agitation, nausea, abdominal cramping, diarrhoea, heart palpitations and sweating. To lower the chance of side effects, your doctor will decrease 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.

Your health care team will closely monitor your use of opioids to maintain effective pain relief and avoid potential side effects. Let them know about any side effects you have. They will change the medicine if necessary.

Common questions about opioids

Most people have questions about taking opioid medicines. Some common questions that may come up are answered below. Your doctor, nurse practitioner or nurse can also discuss any concerns you have.

If you are caring for someone with cancer pain, you may have some other specific questions about opioids. See answers to common questions from carers.

Will I become addicted to opioids?

When people take morphine or other opioids only to relieve acute pain or for palliative care, they are unlikely to become addicted to the medicines. You may experience withdrawal symptoms (see below) when you stop taking a drug, but this is not addiction. For this reason, your doctor will reduce your dose gradually. Talk to your doctor if you are concerned about drug dependence.

Taking opioids for pain relief is different to an addiction. Someone with a drug addiction problem takes drugs to satisfy physical or emotional needs, despite the drugs causing harm. A small number of people who take opioids long-term for pain relief are at risk of becoming addicted. The risk is higher for people who have misused medicines in the past.

Will I need to have injections?

Not necessarily. Strong pain relievers are usually given by mouth in either liquid or tablet form. 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 lozenge form. See a list of the different ways medicines are taken.

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 too soon, will they be less effective 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 my cancer is advanced?

People with cancer at any stage can develop severe pain that needs to be managed with strong pain medicine, such as morphine. Just because you have to use an opioid, it doesn't mean you will always need to take it.

If your pain improves, you may be able to take a milder painkiller or you may be able to stop taking pain medicines.

What if I get breakthrough pain?

While breakthrough pain is relatively common among people diagnosed with cancer, this sudden flare-up of pain can be distressing.

You might get breakthrough pain even though you're taking regular doses of medicine. This breakthrough pain may last only a few seconds, several minutes or hours. 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.

You need to talk to your health care team, who will advise you on how to cope with breakthrough pain. They will usually suggest you take your pain medicine as well as another drug to help with the breakthrough pain. An extra, or top-up, dose of a short-acting opioid (immediate release opioid) may be prescribed to treat the breakthrough pain. The dose works fairly quickly, in about 30-40 minutes.

It is helpful to keep a record of how many extra doses you need so your doctor can monitor your overall pain management. If you find your pain increases with some activities, taking an extra dose of medicine beforehand may help.

"I found the decision to take morphine really difficult. Having made it, I have been taking the slow release tablets for 18 months with no appreciable side effects. Without the morphine the pain would be too debilitating for me to continue doing all the things I do now." - Pete

Will the opioids still work if my body gets used to them?

People who have used opioids for a long time will sometimes become tolerant to the original dose. This means that the body stops responding to the drug, and their doctor will need to increase the dose to achieve the same level of pain control. Your dose of opioids may also be increased if your pain gets worse. There is no benefit in saving pain medicines until the pain is severe.

Can I drive while using opioids?

Doctors have a duty to advise patients not to drive if they are a risk to themselves or others. While taking opioids, particularly during the first days of treatment, you may be less alert, so driving is not recommended. Once the dose is stabilised, you may think that it is safe for you to drive, however, using breakthrough pain medicine can affect your driving ability.

Before you start driving again, seek your doctor's advice and keep the following in mind:

  • 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.
  • 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 download the publication, Assessing Fitness to Drive for commercial and private vehicle drivers, from austroads.com.au.

Can I stop my medicine at any time?

You should only reduce your dose or stop taking opioids in consultation with your health care team. If your pain improves, you may end up needing less or no pain medicine. Morphine and other opioids will need to be decreased gradually to avoid side effects that may occur if you were to stop taking them suddenly. See information about withdrawal side effects.

Other medicines

You may be prescribed other medicines to help relieve your pain, e.g. antidepressants and anticonvulsants. While they are not designed to control pain, they may be used for this purpose, and they often work well for nerve pain. See the table below for a full list.

These medicines are usually given as a tablet you swallow. They can be used on their own or with opioids at any stage of diagnosis and treatment. When prescribed with opioids, these drugs are known as adjuvant drugs or adjuvant analgesics.

Some adjuvant drugs take a few days to work, so opioids are used to control the pain in the meantime. If you are taking an adjuvant drug, it may be possible for your doctor to lower 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 drug. See also Tips for using pain medicines safely.

Other drugs used to treat pain

Drug type (class)
  Generic names Type of pain
  • amitriptyline
  • doxepin
  • duloxetine
  • nortriptyline
  • venlafaxine
burning nerve pain, peripheral neuropathy pain, electric shocks
  • gabapentin
  • pregabalin
burning or shock-like nerve pain
  • diazepam
  • clonazepam
  • lorazepam
muscle spasms with severe pain
  • dexamethasone
  • prednisone
headaches caused by cancer in the brain, or pain from nerves or the liver
  • clodronate
  • pamidronate
  • zoledronic acid
bone pain (may also help prevent bone damage from cancer)
GABA (gammaaminobutyric acid) agonist
  •  baclofen
muscle spasm, especially with spinal cord injury
monoclonal antibodies 
  •  denosumab
bone pain (may also help prevent bone damage from cancer)
local anaesthetic*
  • lidocaine
severe nerve pain

Expert content reviewers:

Dr Tim Hucker, Clinical Lead, Pain Service, Peter MacCallum Cancer Centre, and Lecturer, Monash University, VIC; Carole Arbuckle, 13 11 20 Consultant, Cancer Council Victoria; Anne Burke, CoDirector, Psychology, Central Adelaide Local Health Network, SA, and President Elect, The Australian Pain Society; Kathryn Collins, Co-Director, Psychology, Central Adelaide Local Health Network, SA; A/Prof Roger Goucke, Head, Department of Pain Management, Sir Charles Gairdner Hospital, Director, WA Statewide Pain Service, and Clinical A/Prof, The University of Western Australia, WA; Chris Hayward, Consumer; Prof Melanie Lovell, Senior Staff Specialist, Palliative Care, HammondCare Centre for Learning and Research, Clinical A/Prof, Sydney Medical School, and Adjunct Professor, Faculty of Health, University of Technology Sydney, NSW; Linda Magann, Clinical Nurse Consultant, Palliative Care and Peritonectomy Palliative Care, St George Hospital, NSW; Tara Redemski, Senior Physiotherapist, Gold Coast University Hospital, Southport, QLD.

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