Opioids can affect people in various ways. It can take a few days to adjust to taking strong pain medicines.
Learn more about these side effects:
- Breathing problems
- Constipation
- Dry mouth
- Drowsiness
- Tiredness
- Feeling sick (nausea)
- Itchy skin
- Poor appetite
- Confusion or hallucinations
- Physical dependence
| 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. |
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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.
Constipation
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.
Drowsiness
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 – read about driving and opioids.
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. 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.
Additional resources
This information has been developed by Cancer Council NSW on behalf of all other state and territory Cancer Councils as part of a National Cancer Information Working Group initiative. We thank the reviewers of this information: 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, Co-Director, 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.
Thank you to the Australian Adult Cancer Pain Management Guideline Working Party, Improving Palliative Care through Clinical Trials (ImPaCCT), and the Centre for Cardiovascular and Chronic Care (University of Technology Sydney), whose work contributed to the development of the previous editions of this booklet. Thank you also to the original writers, Dr Melanie Lovell and Prof Frances Boyle AM.
View the Cancer Council NSW editorial policy.
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