What is osteoarthritis and what is diacerein?
Osteoarthritis (OA) is the most common form of arthritis. In OA, the cartilage that protects the ends of the bones breaks down, causing pain and swelling. OA can affect any joint, but the knees, hips and hands are the joints most often studied in clinical trials. In all, 10% of the world’s population aged 60 or older have pain or disability from OA.
Diacerein is a slow-acting drug taken as a pill that may slow the breakdown of cartilage and relieve pain and swelling.
The review searched for studies up to March 2013 about primary osteoarthritis affecting men and women (18 years and older) of any disease severity.
The review shows that in people with osteoarthitis:
- Pain may improve slightly more in people taking diacerein.
- Improvement in physical function is about the same for people taking diacerein,- or a placebo (fake pill). This may have happened by chance.
- Diacerein may slow the process of joint space narrowing slightly of the hip but may have little or no difference on the knee joint as it is seen on an x-ray.
- Diacerein may cause side effects in the lower digestive tract, such as diarrhoea.
Further research is very likely to have an important impact on our confidence in these findings and is likely to change the estimates.
Best estimate of what happens to people with osteoarthritis who take diacerein
Pain after three to 36 months
- People who took diacerein rated their pain to be 9 points lower on a scale of 0 (no pain) to 100 (extreme pain) after taking the medication for three to 36 months (9% absolute improvement).
- People who took diacerein rated their pain to be 34 on a scale of 0 to 100 after taking the medication compared to people who took a fake pill and rated their pain to be 43 points on a scale of 0 to 100.
Physical function after two to 36 months (lower score means worse function)
- People who took diacerein rated their physical function to be 0.30 points lower on a scale of 0 to 24 after taking the medication for two to 36 months (0% absolute improvement).
- People who took diacerein rated their physical function to be 9.3 on a scale of 0 to 24 after taking the medication compared to people who took a fake pill and rated their physical function to be 9 points on a scale of 0 to 24.
Radiographic progression - how the joint looks on an x-ray (reduction in joint space narrowing of at least 0.5 mm)
- Seven more people who took placebo had radiographic progression (absolute difference of 7%).
- 42 of every 100 people who took diacerein experienced reduction in joint space narrowing of at least 0.5 mm compared to 49 of every 100 people who took a fake pill.
Quality of life
- There was no difference in quality of life of people who took diacerein compared with non-steroidal anti-inflammatory drugs (NSAIDs). This may have happened by chance.
- Twenty-six more people who took diacerein experienced diarrhoea as a side effect (absolute difference of 26%).
- 36 of every 100 people who took diacerein experienced diarrhoea as a side effect compared to 10 of every 100 who took a fake pill.
Diarrhoea was the most common side effect and usually occurred during the first two weeks after the start of diacerein.
People who took diacerein were not more likely than people who took a placebo to stop taking the medication because of side effects.
In November 2013, the European Medicines Agency Pharmacovigilance Risk Assessment Committee (PRAC) recommended that the marketing authorisation of diacerein should be suspended across Europe because of harms outweighing benefits. However, this guidance is not final as the PRAC recommendation will be re-examined.