This information has been prepared for our web site by  Dr. Arthur Penberthy, neuro-anaesthetist, and details some of the pain relieving drugs (analgesics), which may be used to manage pain after your surgery.

Why is treatment of pain important after surgery?

Good pain control helps you to be more comfortable while you heal after surgery. This will help you to move, breathe more easily and improve recovery.

How much pain should I have after surgery?

It is likely that you will have some pain after your surgery, although this is not normally severe. The amount of pain a person experiences after an operation depends on the type of surgery performed and will vary from person to person.

How do I know when to treat my pain?

  • Do not wait until your pain becomes severe before taking pain relieving medications. Pain is easier to control when it is mild to moderate.
  • During the first few days after surgery, you may need to take stronger pain relieving medications. The need to take these medications will lessen as your body heals. Take pain relieving medications about an hour before planned activities that may cause discomfort.
  • Do not mix pain relieving medications from hospital and from home. Only take the pain relieving medications that have been prescribed for you. It is important to let the doctors in hospital know if you have been taking regular analgesics at home and prior to your surgery.

How do I know which pain relieving medications
to take?

You will be prescribed several pain relieving medications depending on the severity of the pain you experience. These may include:

  • Paracetamol

This is a safe and effective painkiller. We recommend that you take this medicine regularly, i.e. two tablets four times daily (eg. breakfast/lunch/dinner/bedtime). Limit the daily dose to a maximum of eight tablets. Do not take Paracetamol for more than seven days. Side effects are uncommon but Paracetamol can be dangerous in over-dosage.

Note there are many other products which contain Paracetamol -to avoid over-dosage, it is important that these are not taken as well as the Paracetamol prescribed after your operation. Other Paracetamol brands include Panamax®, Panadol®, Febridol®, Dymadon P®. There are also many cold and flu preparations, which contain Paracetamol at various strengths.

Let your doctor know if you are taking Warfarin, as there may be an interaction with Paracetamol.

  • Naproxen and Voltaren

These are non-steroidal anti-inflammatory (NSAID) type medicines. The dose is one tablet three times per day or as required with food (eg. breakfast, lunch and dinner).

There are many other NSAID type drugs which should not be taken as well as your Naproxen or Voltaren, including Ibuprofen (Brufen®, Rafen®, Nurofen®), Indomethacin (Indocid®), Piroxicam (Mobic®) and Mefenamic Acid (Ponstan®).

Usually Naproxen or Voltaren will not be prescribed if you have a history of stomach ulcers, allergy to NSAID drugs or are pregnant or breastfeeding. Caution is required in patients with asthma, bleeding disorders, taking anticoagulants (eg Warfarin) and heart or kidney failure.

Naproxen or Voltaren can cause indigestion, stomach pain, nausea and diarrhoea. If you experience any of the following more severe side effects such as blood in vomit, blackened stools, skin rash, shortness of breath and fluid retention (eg. Swollen ankles) stop Naproxen and let your doctor know immediately.

Drug Interactions with blood thinning medications (eg Warfarin) and blood pressure lowering medications*

  • Morphine, Oxycodone (Endone® and Oxycontin SR®)

These medicines should only be taken when required or as directed for moderate to severe pain. Morphine can be given through a drip or as an injection under the skin.

Endone® is an immediate-release morphine-like tablet which can be taken up to every three hours. The dose is usually 2.5-10 mg (½ -2 tablets)

Oxycontin® is a sustained-release morphine- like tablet which means that the tablet gradually releases the drug into your body. The dose, which must be swallowed whole, is usually 10-20 mg twice daily taken regularly (every 12 hours). It is important to remember that Oxycodone may cause an additive effect with sedatives and/or alcohol*. We need to know if you usually take any other strong (opioid) pain killers such as Morphine* Also advise your doctor if you have had seizures (fits) or a head injury.

All opioids can cause side effects including nausea, dizziness, headache, confusion, drowsiness and skin rash. Let your doctor know should you experience any of these symptoms. Constipation is common and you may be prescribed laxatives to lessen this side effect.

  • Tramadol

Tramadol may be prescribed for moderate to severe pain. The normal dose is 50-100 mg up to four times daily (less in patients who are elderly or have kidney disease).

If you have a history of seizures (fits) or are pregnant/breastfeeding, please let your doctor know, as you may not be able to take Tramadol in these circumstances. Side effects of Tramadol include nausea, constipation, drowsiness, sweating and, rarely, fits.

Importantly, this medicine interacts with other drugs* including antidepressants, Warfarin, alcohol and St John’s Wort.

*This is not the complete list of drug interactions. Please inform the doctor or pharmacist of all the medicines you are taking.


  • Endep

This is a tablet used to dampen down nerve pain. In the past, the tablet has been used in higher doses to treat depression. Nowadays, smaller doses are used for nerve pain control. Starting dose is 10mg at night, increasing to 25 – 50mg at night. The main side effects are dry mouth and sedation.

  • Patient controlled analgesia (PCA)

PCA is a method of giving you pain relief (usually Morphine) through your intravenous line (drip). The advantage of PCA is that you can control the amount of pain relieving medication you give yourself. The system consists of a pump, which contains the pain relieving medication. This is connected to your intravenous line. A push button is connected to the pump. Whenever you experience pain, all you need to do is push the button and the pump will deliver a set dose of pain relieving medication to you through your drip. The PCA system is safe and it is difficult to overdose on the pain medication because the pump has a lockout mechanism. This means that if the pump delivers a dose of pain relieving medication to you, it will not deliver another dose of medication to you for a predetermined period (usually 5 minutes), even if you push the button. After this lockout period, the pump will once again deliver pain relief to you if you push the button.