Osteoarthritis (OA) is a common joint disorder, but current treatments only help the symptoms and do not reverse or halt its progression. Analgesics and nonsteroidal anti-inflammatory drugs (NSAIDs, e.g. ibuprofen) are typical treatments. Topical and oral treatments are used. Topical treatments have the advantage of preventing systemic side effects. Extracts of arnica (Arnica montana, Asteraceae) are also used topically to treat symptoms associated with OA. The purpose of this randomized, double-blind, reference-controlled study was to compare the efficacy of a specific commercial arnica gel with an NSAID gel.

Patients (n=204) from 20 general practice clinics in Switzerland, diagnosed with radiologically confirmed and symptomatically active OA of interphalangeal joints (fingers) of the hands participated. Patients received either ibuprofen gel 5% (Optifen Gel, Spirig Pharma Ltd; Egerkingen, Switzerland) or arnica gel (A. Vogel Arnica Gel; A. montana fresh herbal tincture 50 g/100 g gel; drug-to-extract ratio of the tincture 1:20, Bioforce AG; Roggwil, Switzerland). This arnica preparation was chosen because (1) it has published evidence from preclinical studies of some anti-inflammatory action, (2) the preparation has published evidence of skin penetration, and (3) it is available as a gel that is similar to the ibuprofen gel, so it could be blinded with the control ibuprofen gel during the study.

Patients were instructed to rub in a 4 cm strip of gel to the affected joints 3 times daily for 3 weeks. They were told not to wash their hands for 1 hour after applying the treatment. Patients were dispensed a preset number of 500 mg paracetamol tablets (acetaminophen) as “escape treatment,” often referred to as a “rescue treatment” (i.e., the patients were allowed to use the acetaminophen for pain that was not bearable and for which the tested treatment may not provide adequate pain relief). Subjects were not allowed to use the rescue medication within 24 hours prior to the final evaluation and were asked to return any unused tablets at the end of the treatment course. Pain and functional capacity were assessed.

The results demonstrate that the arnica gel was “non-inferior” and similar to ibuprofen gel in terms of hand functional capacity, pain intensity, number of painful joints, duration and severity of morning stiffness, or acetaminophen consumption. When blinded to treatment, neither patients nor doctors could distinguish between the effects of the 2 treatments. Global efficacy evaluation by physicians was rated very good or good in 56.5% of the subjects using the ibuprofen gel and 64.0% of those using the arnica gel, while patients rated efficacy very good or good in 58.8% (ibuprofen) and 64.1% (arnica) of cases. Patients’ acceptance of the gel treatment was 76.5% and 78.7% (very satisfied or satisfied; ibuprofen and arnica, respectively). In these secondary measures the arnica gel was rated slightly better than the ibuprofen gel.

Both treatments were well tolerated. Adverse events were reported by 6 patients (6.1%) on ibuprofen and by 5 patients (4.8%) on arnica.

The authors conclude that short-term use (up to 3 weeks) of arnica gel improves pain and function in OA of the hand and that the effects were indistinguishable from those of ibuprofen gel. According to the data of this well-designed study, the arnica gel preparation used in the study can be used as an alternative to ibuprofen gel when treating OA of the hand joints. It is important to emphasize that these clinical findings may not be extended to other topical arnica preparations, which may contain a different extract and concentration. Likewise, similar benefits may not be obtained unless the specific arnica product evaluated in this trial is used as described in this protocol.

—Heather S. Oliff, PhD