In treating knee osteoarthritis pain, topical medication for pain relief is safer and more effective than opioids, according to a new meta-analysis.
The paper, which appears in BMJ, compared the benefits and harms of different doses of commonly prescribed treatments for hip and knee osteoarthritis, including oral non-steroidal anti-inflammatory drugs (NSAIDs), topical NSAIDs, opioids, and acetaminophen (Tylenol). The meta-analysis looked at 192 large, randomised clinical trials with a total of over 102 000 participants.
Researchers found, regardless of preparation or dose, opioids did not significantly relieve pain for osteoarthritis patients. They also found that topical Diclofenac – known to consumers as Voltaren – is effective in treating knee osteoarthritis.
The topical treatment, which can be purchased over-the-counter, is generally safer than oral NSAIDs and should be considered as first-line pharmacological treatment for knee osteoarthritis, the study authors say. Osteoarthritis affects millions of Canadians.
Study lead author, Dr. Bruno R. da Costa, Acting Director of the Applied Health Research Centre (AHRC) at the Li Ka Shing Knowledge Institute of St. Michael’s Hospital, stated that recent clinical practice guidelines recommend the lowest possible dose to minimise the risk of adverse events.
However, he said, “it is currently unclear what the lowest but still effective doses of these drugs are. Osteoarthritis affects more than 4.6 million people in Canada. Our findings allow physicians, patients, or their caregivers to have a better understanding of which of these treatments at their lowest doses would be safest while still being effective.”
“Although there is robust evidence about the harmful effects of opioids, and international concerns around the opioid epidemic, opioids remain among the most prescribed drugs for osteoarthritis pain in Canada, the United States, the United Kingdom and Australia.”
Dr da Costa said that none of the opioid interventions, regardless of dose, seemed to have a clinically relevant effect on pain or physical function. Opioids should therefore only play a secondary role in osteoarthritis treatment, when conventional treatment is exhausted.
What was most surprising was that maximum recommended daily doses of opioids do not have an effect in osteoarthritis pain that patients would consider relevant. They did not see an association between higher opioid doses and greater pain relief.
Lower doses of topical diclofenac (Voltaren) also have a similar beneficial effect to the most effective oral NSAIDs in knee osteoarthritis – an important finding as some patients with gastrointestinal complaints and other comorbidities. Adverse events of topical NSAIDs are minimal. The topical diclofenac trials had only knee osteoarthritis, and in hip osteoarthritis the depth is likely too great for any benefit.
The next step is to better understand the safety of oral NSAIDs in patients with comorbidities, and long-term use on an as-needed-basis with varying versus fixed daily doses. It would also be useful to identify if there are patients who have exhausted treatment options but could benefit from opioids or acetaminophen.
Source: Unity Health
