://module3 Opioids and complex pain management page 5/8 <previous next >
Side effects of opioids
Constipation - this is the most common side effect. To reduce this, all patients started on opioids should be started on a laxative.
Nausea and vomiting - this occurs in upto 50% of patients on opioids for moderate to severe pain.
Drowsiness and confusion - this is particularly common in elderly patients. All patients should be warned about initial drowsiness (which often improves after 3-5 days on the drug). Concurrent psychotropic drugs can make this worse, and sometimes changing to a less sedating drug can help (eg from chlorpromazine to haloperidol). Patients with continuing marked sedation may improve when changed to a different opioid (eg from morphine to oxycodone or hydromorphone).
Respiratory depression - this is a less common side effect in cancer patients with pain as the pain acts as a physiological respiratory stimulant, balancing the depressive effect of the opioids. However, it can still occur (especially in heavily sedated patients), and can be counteracted by administering naloxone at a dose of 0.2 - 0.4 mg. This may not be appropriate in all patients.
Rare side effects - these include opioid induced psychosis, or symptoms related to histamine release (pruritis, bronchospasm). These patients may need to be changed to another strong opioid.
We will now look at changing between strong opioids