Current global international practice guidelines recommend glucosamine sulfate for the treatment of knee osteoarthritis symptoms. These recommendations are based on the clinical evidence, which has been assessed in a Cochrane Review (Towheed, 2009) including 25 trials with 4963 patients. In these trials, crystalline glucosamine sulfate (Viartril-S, Dona, or Xicil
Rottapharm Group, Monza, Italy) were used, that is, the original glucosamine sulfate described in most of the literature and available as a prescription drug for osteoarthritis in several European and other countries and as a nutritional supplement in the United States. The efficacy is apparently restricted to glucosamine sulfate, while glucosamine hydrochloride was never shown to be effective. In particular, only the patented, prescription formulation of crystalline glucosamine sulfate (Viartril-5 1500mg) has shown efficacy in clinical studies, while the data for other glucosamine sulfate formulations are at best conflicting. Indeed, a complete pharmaceutical package and pharmacokinetic studies characterize the prescription product, at the standard oral dosage of 1500 mg once daily, for which 3 pivotal clinical trials exist (Reginster, 2001
Pavelka, 2002
Herrero-Beaumont, 2007). These are large, high quality, randomised, placebo-controlled, doubleblind, long-term trials from a minimum of 6 months to 3 years of continuous treatment. A recent meta-analysis (Reginster, 2007) of these trials showed an effect size of 0.27 on knee pain and of 0.33 on function, i.e., a small to moderate effect in line with that of available treatments for osteoarthritis, but with the advantage of the long-term application and the excellent tolerability. In the two 3-years trials, glucosamine sulphate was also able to significantly reduce the rate of joint space narrowing, compared to placebo. Furthermore, pooled post-hoc analyses in patients who were in these trials for at least 12 months indicated a 57 percent reduction in rate of undergoing total knee replacement during a mean foHow-up of 5 years after termination of the 3-year trials and drug discontinuation (Bruyere, 2008). The superior clinical results of these studies could be explained by the pharmacokinetics and excellent bioavailability of Viartril-5 as compared with other glucosamine (S. Persiani et al - Osteoarthritis and Cartilage (2005) 13, 1041-1049). Finally, an economic evaluation showed the cost-effectiveness of glucosamine sulfate in patients with knee osteoarthritis (Scholtissen 2009).