Fentanyl patches improve pain control and function in osteoarthritis

The effectiveness and safety of fentanyl patches was recently examined in a study published by Clinical Rheumatology. In this study,the use of fentanyl patches was assessed for those osteoarthritis sufferers who still experience pain despite using other pain controlling medications.The trial was conducted over eight weeks, assessing osteoarthritic pain of the hip and knee joints in terms of improvement in pain control. Patients using the patches reported on changes in pain their pain level and were examined to assess mobility of the affected joint. Patients were also interviewed to see if use of the patches improved their ability to perform common daily activities. At the end of eight weeks, 65% of patients were found to have experienced an improvement in pain management and approximately 50% were managed with the strength of patch they were first trialled on (25mcg/hr). Fentanyl patches also resulted in some improvement in joint mobility and general ability to perform daily activities. The majority of side effects experienced were mild to moderate and included nausea, dizziness and headache. The outcomes of this study therefore back the guidelines for the use of pain relieving medications (opioids), including fentanyl patches, for a particular group of osteoarthritis patients.

Osteoarthritis is a leading cause of disability. The non-opioid treatments available, including paracetamol and anti-inflammatories, are limited both in terms of ability to manage pain and side effects. While paracetamol can be helpful in mild or moderate pain, more severe pain is poorly controlled by paracetamol, and long term use has been associated with liver damage.

Anti-inflammatories are a treatment option that are useful in more severe conditions but some types, known as non-selective anti-inflammatories, have a high risk of side effects such as bleeding.

Opioids medications such as fentanyl therefore have been considered for treatment of osteoarthritis in patients who experience moderate to severe pain. Opioids are a group of medicines with a long history of use for their pain relieving effects in a range of chronic pain conditions. They have predictable side effects and are considered well tolerated in long-term use. The American Pain Society has also approved opioids for use in osteoarthritis when other medication has not provided a reasonable level of pain relief and a person’s quality of life is reduced.

Although this study did not evaluate the placebo effect, fentanyl patches have been previously studied and found to be effective for chronic pain. There is also a previously published study examining the placebo effect of fentanyl patches which shows their effectiveness in the management of osteoarthritic pain.

This study was conducted at rheumatology and clinical research centres in Canada and evaluated the use of fentanyl patches in 81 patients satisfying American College of Rheumatology diagnostic criteria for osteoarthritis of the hip or knee which limited their ability to participate in every-day activities. Participants also had a moderate to severe pain score in the hip or knee and pain control assessment of excellent to very poor.

Patients began the trial with 25mcg/hr patches for three days. After this time the strength could be increased by addition of one additional 25mcg/hr patch at intervals of 72 hrs. Paracetamol was allowed up to a total of 4g/day, and laxatives and antinauseant agents were given according to standard protocols during the first week, and thereafter on an as needed basis.

Patients reported treatment outcomes at the beginning of the trial, days 3, 6, 9, 14, 28, and at the conclusion of the trial. As a result of this study, 75% of patients reported an improvement in pain control by day 14 and 65% of patients reported that their pain was still well controlled at eight weeks.

The mean reduction in pain intensity was 29% representing a clinically measurable change. 58% of patients also reported moderate to excellent pain control. An improvement in joint mobility was also seen in over half the patients at eight weeks, with many patients reporting an increased ability to participate in every-day activities.

At the end of treatment 49% of patients had experienced pain control with the strength of patch they were first trialled on (25mcg/hr). The average daily dose of paracetamol required was 1.2 g/day.

The side effects reported were those typically reported for strong pain relieving medications (opioids) and were not a major concern for most patients. One side effect that occurred at a lower rate than expected was constipation, which occurred at a lower rate than is seen when this type of medication is used as tablet.

Overall, the use of fentanyl patches resulted in an improvement in pain management, quality of life and mobility for this group of patients. The use of fentanyl patches as per current recommendations was supported by this study for those suffering from osteoarthritic pain not managed with weaker pain controlling medication.

When considering this information, it is recommended that you discuss your treatment options in detail with your doctor to determine if this medicine is suitable for you. Fentanyl is a prescription only medicine and should only be used as directed by your doctor.

(Source: Choquette D, McCarthy T, Rodrigues J et al. Transdermal fentanyl improves pain and functionality in patients with osteoarthritis: an open label Canadian trial. Clinical Rheumatology 2007 : January 2008)