Efficacy and safety of willow bark extract for pain reduction in patients suffering from musculoskeletal disorders (MSD) has been shown in clinical short term trials. Therefore this observational study over 6 months should evaluate patterns of treatments like mono- or combinations therapy, dosage and safety during long-term treatment under pragmatic conditions with the aqueous willow bark extract STW 33-I, (Proaktiv(®); drug-extract-ratio 16-23:1).
The patients were treated with STW 33-I; comedication with other NSAIDs and opioids was allowed. An extensive case report form including pain questionnaires and patient diary was used for outcome evaluation.
Four hundred and thirty-six patients with rheumatic pain mainly due to osteoarthritis (56.2%) and back pain (59.9%) were included. During the study the mean reductions from baseline value 58.4±22.6-31.8±22.5 after 24 weeks in the pain intensity scale (VAS 0-100mm) were significant even after 3 weeks with a reduction by 26 mm (45.6% of the baseline value) at the end of the study. The relative reductions of the weekly means of the daily patient self-rated scores of the pain (6-point Likert-scales) were between 33% and 44% of the baseline values during the course of the study. We present results of subgroups according their analgetic/antiphlogistic comedication. The distribution and specification of the main adverse events and the ratings of the treatment showed a good tolerability. No relevant drug interactions were reported.
These data suggest that STW 33-I can be used as a basic treatment in the long-term therapy of painful musculoskeletal disorders and that it can be combined with NSAIDs and opioids if necessary.