What is the evidence for dimethyl sulfoxide (DMSO) and methylsulfonylmethane (MSM) in the treatment of osteoarthritis of the knee?
AMSTAR Rating
Summary
Patient Population:
326 participants in total – All of whom were experiencing OA of the knee. Average age ranged from 56-62 years.
Intervention:
Dimethyl sulfoxide (DMSO) or methylsulfonyl-methane (MSM). DMSO is a topical agent (diluted for therapeutic use; 60-90% – 2 trials used preparations of 25% and 45.5%). MSM used both orally and topically. Suggested oral dose is 4-6 g/day. The single trial included in the review administered MSM 3g BID. All trials assessed treatments as alternatives not supplements – all other systemic and topical meds were stopped before trial commencement.
Comparison:
The authors identified 3 trials that met all inclusion criteria (2 DMSO, 1 MSM). The doses of DMSO used in the trials were below the current therapeutic recommendations – and for an inadequate duration (less than 3 months). Assessment of methodological quality demonstrated that the 3 trials included were of high quality. Note that data from DMSO and MSM trials are pooled together in the meta-analysis.
Outcome:
- Pain: A fixed effect meta-analysis demonstrated a small effect in favour of DMSO/MSM when compared to placebo (6.3mm; 95% CI 2.41 to 10.27). However, this analysis was associated with significant heterogeneity (p<0.04).
- Adverse effects: GI upset, skin irritation, garlic-like taste, breath and body odour (DMSO).
- Adverse effects: allergy, GI upset, skin rashes (MSM).
