A pilot study was done to determine if potassium humate, a natural substance derived from brown coal, with
known anti-inflammatory properties, is safe and effective in reducing pain and inflammation in osteoarthritis of the knee.
This was conducted as a randomized, double-blind, placebo-controlled, single centre, cross-over. Participants were
enrolled for a total of 14 weeks, starting with an initial 1-week washout period, after which they were randomly assigned
to either potassium humate or lactose, administered orally for 6 weeks at a dosage of 600mg three times daily. Following
another 1-week washout period, participants were crossed over to the other treatment for another 6 weeks. Participants
were not permitted the use of anti-inflammatory medications. Paracetamol was allowed as rescue medication for the
duration of the trial. The primary efficacy variable were the WOMAC™ scores (visual analogue version) for pain,
stiffness, physical function and total score and health related issues using the RAND 36 levels, rescue medication use,
adverse effects and tolerability.
28 participants were enrolled and 21 participants successfully completed the protocol. A carry-over effect in the stiffness
subscale was observed. There was a significantly greater clinical benefit with potassium humate over placebo with
reduction in all the WOMAC subscale scores for pain. After adjusting for baseline, potassium humate showed a greater
reduction in hs-CRP levels when compared to placebo. Tolerability was good for all groups. Safety parameters remained
unchanged, except for an increase in the GGT-levels (n=4 in potassium humate group, n=2 in the placebo group). Levels
of GGT returned to baseline within 2 weeks of discontinuation of therapy. In conclusion, potassium humate showed
possible benefit over placebo in patients with OA of the knee, with a statistically significant reduction in hs-CRP levels.
The small sample size and the carry-over effect limited further interpretation of data.