Opioid (pain reliever) infusion

Disclaimer: This fact sheet is for education purposes only. Please consult with your doctor or other health professional to make sure this information is right for your child.

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When children have strong pain due to surgery, injury or illness, they need constant pain relief.

Morphine and some other strong pain relievers (opioids) can be given through an intravenous line (IV). This allows your child to receive pain relief constantly, without break or delay.

If your child needs pain relief using an IV, an Anaesthetist/Doctor or a member of the Acute Pain Service will explain how this works and how we will do this for your child.

How does it work?

The opioid medicine, usually morphine or fentanyl, is given using a special pump attached to the IV. This pump is programmed to give the right amount of pain reliever continuously, based on your child’s weight. 

The infusion can be turned up by the doctor and nurse if your child’s pain goes up, or it can be turned down by the doctor or nurse if your child’s pain goes down.

Other pain relievers such as panadol (paracetamol) or nurofen (ibuprofen) may also be used with the opioid infusion.

How safe is an Opioid Infusion?

There are many safety features built into the IV infusion machine and into the way that the medicine is ordered.

A Doctor /Anaesthetist or member of the Acute Pain Service will order the infusion and will check your child before starting the pain relieving infusion. Please tell this person if you know your child has medication allergies.

The dose of pain relieving medicine used is specific to your child’s weight and the amount of pain relief needed. 

The nurse will check your child often: to assess your child’s pain level, breathing rate, heart rate, oxygen levels, sleepiness, and if necessary blood pressure. If you or your child have any questions or concerns between these checks just call the nurse. 

You play an important part in caring for your child as you know your child best and can help assess your child’s pain at and between these formal checks.

While an opioid infusion is being used, your child will be reviewed by either the Acute Pain Service, or your child’s treating team on a daily basis and more often if needed.

Are there any side effects of opioid infusions?

The most common side effects of opioids are nausea and vomiting.  The doctors and nurses are able to give other medicines to help with this and still provide the necessary pain relief.

Constipation (difficulty and/or pain passing a bowel motion) can also occur due to the opioid. Other medicine may help to prevent this.

Sometimes opioids can cause itching, which is also treatable.

Opioids can make your child feel a little drowsy, but if your child is able to sleep it usually means your child’s pain is well controlled. Sleep also helps recovery from operations, but if your child seems too sleepy please tell the nurse.

Opioids can slow down breathing, but the effect depends on the amount of the opioids given. Some children with severe snoring or sleep apnoea (pauses in breathing) will be closely monitored and may need extra oxygen while being given opioids.

A few children may have some mild behaviour changes or muddled thinking. These will disappear when the medicine has stopped but if you are worried, please tell a doctor or nurse.

Will my child get addicted to the pain reliever drip they are receiving?

Children do not become addicted to the pain relieving medicine if it is being given to relieve pain from an operation or sickness. If the opioid infusion is used for more than a week, your child’s body may become used to the pain relieving medication, in which case it will be reduced slowly.

After an operation, an opioid infusion is needed until the pain can be managed by oral pain medicine.  Remember that every child is different, some operations can cause more pain and the infusion is needed for longer.

Your child may need pain-relieving medicines that can be given by mouth after this infusion is stopped. Your doctor will explain these to you.


  • You know your child best. If at any time you are concerned about your child or have any questions, please talk to a nurse or doctor.
  • Pain relieving medicine given in an infusion is a safe way of providing pain management.
  • Your child will be checked at least hourly by the nurse and/or doctor. 
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