NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update

Opioid patches: safe conversion from oral therapy

Buprenorphine patches are available as BuTrans® and Transtec® patches. The Scottish Medicines Consortium concluded that buprenorphine patches were not cost-effective in the treatment of severe opioid responsive pain conditions and did not recommend their use. These patches are non-Formulary in NHSGGC. Oral morphine remains the first-line choice of strong analgesic for cancer and non-cancer pain.

 

Two near misses have been reported by a community pharmacist involving the conversion of tramadol to buprenorphine patches. Both cases involved patients above the age of 80 suffering from chronic pain. Both patients were reporting that their pain was poorly controlled.

 

In each case, the GP had converted the prescribed dose of tramadol to buprenorphine and rounded up to the next available patch since the pain was not well controlled. In one case, the GP was unaware that the patient had been experiencing nausea with the prescribed dose of tramadol so was in fact taking less than half the prescribed dose.

 

When undertaking conversion from one opioid to another, the guidelines recommend decreasing the original equivalent morphine dose by 25-50% to prevent adverse effects. In both cases, the prescription issued was for a dose double that which would be recommended by the conversion tool approved within NHSGGC.

 

Learning Points

 

In order to prevent this type of issue, prescribers should consider the following: 

 

  • Buprenorphine patches should only be prescribed for patients requiring Step 3 analgesia when Formulary alternatives have been ineffective or unsuitable.
  • When converting opioids, ensure you know what dose the patient is actually taking, rather than what dose has been prescribed.
  • When converting one opioid to another, the equivalent daily dose of oral morphine should be calculated using the original daily dose, and then reduced by 25 to 50%.
  • Use the opioid conversion tool
  • Buprenorphine patches are generally more difficult to titrate than oral opioids.

See the NHSGGC Chronic Non Malignant Pain Opioid Guidelines for more information.