Ibuprofen gel or capsaicin cream, which one shall I use to treat my knee osteoarthritis pain?
Full reference: Persson, M.S., Stocks, J., Sarmanova, A., Fernandes, G., Walsh, D.A., Doherty, M. and Zhang, W., 2020. Individual responses to topical ibuprofen gel or capsaicin cream for painful knee osteoarthritis: a series of n-of-1 trials. Rheumatology. doi.org/10.1093/rheumatology/keaa561
Ibuprofen gel and capsaicin cream are two commonly used treatments for painful osteoarthritis of the knee. Based on previous studies involving hundreds of people, we know that they provide similar levels of pain relief on average. But does that mean that each person that tries the two treatments finds that they give the same amount of pain relief? Our clinical experience would suggest that it does not, however, no studies had tested this before.
We invited 22 men and women to take part in a study that involved switching between an ibuprofen gel and a capsaicin cream in a random order. Each person started off by applying one of the treatments to their painful knee for four weeks. Before starting and at the end of the four weeks, we asked them to grade the levels of pain in their knee on a 0-10 scale (from no pain to very intense pain). They then had a break to allow their pain levels to return to normal, before switching to the other treatment. Once again, they recorded their pain levels before and at the end of the four weeks. The process was repeated for two or three times.The difference was determined when one treatment was better than the other by one grade or more for at least two times.
The overall pain relief score when the 22 people were using ibuprofen gel was similar as that when they were using capsaicin for knee pain. However, of these 22 people, four (18%) experienced more pain relief from ibuprofen, nine (41%) had more pain relief from capsaicin, four (18%) had the same pain relief from the two treatments, and five (23%) could not be determined.
What we have learnt from this study is that although ibuprofen gel and capsaicin cream are equally effective on average, individuals respond to them differently. Treatment should be tailored to individual patients to maximise the benefit.