Opioids for mild to moderate pain

• Available as codeine phosphate tablets 15mg, 30mg and 60mg and as liquid preparations 15mg/5ml and 25mg/5ml.
• Also available in combination with paracetamol 8mg/500mg, 15mg/500mg, 30mg/500mg.
• Codeine must be metabolised to morphine to achieve most of its analgesic effect.
  • 5 to 10% of people lack the liver enzyme which enables this to happen (CYP2D6) and therefore pain relief will not be achieved but adverse side effects will still occur.
  • In contrast, ultra-rapid metabolisers produce more morphine and are more prone to toxicity.
• Several active metabolites are renally excreted.
• Avoid in stage 4 and 5 Chronic Kidney Disease.
• Maximum oral dose: 240mg/24 hours.

• Similar to codeine in structure and analgesic effect.
• Available as 30mg tablets
• Dihydrocodeine is metabolised by the liver enzyme CYP2D6 to an active metabolite.
• No evidence to suggest that analgesic effect is affected by an individual’s ability to metabolise dihydrocodeine.
• Active metabolites are renally excreted.
• Avoid in stage 4 and 5 Chronic Kidney Disease.
• Maximum oral dose: 240mg/24 hours.

• Oral and injectable dose forms available.
• Chemically unrelated to morphine. Opioid and non-opioid properties.
• Renally excreted.
• Use with caution in stage 4 and 5 Chronic Kidney Disease and severe liver failure. Consider increasing the dosage interval of the immediate release preparation to 12 hourly and to avoid the modified release preparation.
• Tramadol requires the liver enzyme CYP2D6 to help with its metabolism and can therefore be poorly tolerated by some individuals.
• Contra-indicated in individuals taking Monoamine Oxidase Inhibitors (MAOIs) or in those with epilepsy.
• Avoid or use with caution in individuals taking Selective Serotonin Reuptake Inhibitors (SSRIs) or Tricyclic Antidepressants (TCAs) due to risk of serotonin syndrome and of lowered seizure threshold.
• Maximum oral dose: 400mg/24 hours

• Available as a 7-day patch (for example Butec®). At low doses (5micrograms to 20micrograms/hr) is used to treat moderate pain.
• Buprenorphine patches are contra-indicated in patients with acute (short-term) pain and in those who need rapid dose titration for severe uncontrolled pain.
• Undergoes hepatic metabolism to norbuprenorphine which has little clinical activity and does not cross the blood-brain barrier.
• Unchanged buprenorphine is excreted through the biliary system.
• Buprenorphine does not accumulate in renal impairment and therefore may be a good Step 2 Opioid in stage 4 and 5 Chronic Kidney Disease.

Refer to buprenorphine information sheet.

Note: A 3-day patch (35microgram, 52.5microgram and 70microgram/hr) and a 4-day patch (35microgram, 52.5microgram and 70microgram/hr) are available. At higher doses (greater than 20microgram/hr), buprenorphine is used to treat moderate to severe pain.