Side effects of opioids

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:

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.


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 – go here if you have 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.

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Instructions for downloading and reading EPUB files

Apple devices

The iBooks application must be installed on your Apple device before you can read the EPUB.
Different ways to download an EPUB file to your Apple device:

  • email EPUB files to yourself and transfer the attachment to iBooks.
  • copy EPUB files into DropBox (or a similar service) and use the DropBox app to send them to iBooks.
  • open EPUB files directly from Mobile Safari and open them in iBooks, where they are saved automatically by downloading the EPUB from the website.

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To download an EPUB file to your Kobo from a Windows computer:

  • download and save the EPUB directly onto your desktop.
  • connect your Kobo to your computer using the USB cable and tap “Connect” on your eReader.
  • select “Open folder to view files” to view the contents of your Kobo.
  • navigate to where you have stored your EPUB file in “Finder”, in documents or downloads, and drag and drop it into the Kobo window. You can now disconnect your Kobo to read the eBook.

To download an EPUB to your Kobo from a Mac:

  • download and save the EPUB directly onto your desktop.
  • connect your Kobo to your computer using the USB cable and tap “Connect” on your eReader.
  • open your “Finder” application.
  • select “Kobo eReader” from the listed devices to view the contents of your Kobo.
  • navigate to where you have stored your EPUB file in “Finder”, probably in documents or downloads, and drag and drop it into the Kobo window. You can now disconnect your Kobo to read the eBook.

Turn on your Kobo and your EPUB will be located in “eBooks”, while a PDF will be located in “Documents”.
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Sony Reader

To download an EPUB file on your Sony Reader™:

  • ensure you have already installed the Reader™ Library for PC/Mac software
  • select the eBook you want from our website and click the link to download it.
  • connect the Reader™ to your computer.
  • open the Reader™ Library software and click “Library” in the left-hand pane and select the eBook to view it.

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Amazon Kindle 2nd Generation devices

EPUB files can’t be read on the Amazon Kindle™. However, like most eReaders, Kindle™ 2nd Generation devices are able to display PDFs. We recommend that you download the PDF version of this booklet if you would like to read it on a Kindle™.
To transfer a PDF to your Kindle™ via USB cable from your computer or Mac:

  • download the PDF directly onto your computer.
  • connect the USB cable to your computer’s USB port, and the micro USB end of the cable to your Kindle™. Note: the Kindle™ won’t be available as a reading device while it is connected to your computer until it has been disconnected.
  • open the Kindle™ drive and several folders will appear inside. The “Documents” folder is where you will need to copy or drag the PDF to.
  • safely eject your Kindle™ from your computer and unplug the USB cable. Your content will appear on the Home Screen.

Kindle also provides a Kindle Personal Documents Service that allows users to send documents as an attachment directly to your eReader. For more information on this service, visit
For more information on accessing a PDF on your Kindle™, visit, log in to your account and click on Personal Document Settings.
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Android and PC

You can also download and open eBooks on Android devices and PCs with appropriate apps or software installed. Suitable eReader apps for Android include Google Play Books, FBReader and Moon+ Reader. Suitable software for PCs include Calibre and Adobe Digital Editions.

This information was last reviewed in September 2018
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