[Analgesic and muscle tonus normalizing effect of flupirtine retard in chronic back pain. Results of a standardized therapeutic evaluation applying objective methods for measuring pain pressure threshold, pain pressure tolerance and muscle tension].

Abstract Chronic back pain is mainly caused by painful tension in the back muscles. Thus, analgesics with muscle tone decreasing effects that apparently normalize increased muscle tonus through specific modes of action without disturbing normal muscular movement are an important therapeutic option. Flupirtine retard (Katadolon S long) has provided such an option since 2006. To impartially evaluate the muscle tonus normalizing effects of flupirtine retard by applying specific, objective test methods in patients with chronic musculoskeletal pain under routine practice conditions. Prospective standardized evaluation of a treatment with flupirtine retard in 30 patients with continuous chronic, therapy refractory back pain. Measurement of general pain intensity, pain pressure threshold and pain pressure tolerance for trigger-point related pain and muscle tension in the affected back muscles before and during flupirtine retard treatment were performed in a standardized manner. In comparison to the reproducible, constant initial values, the two-week treatment with flupirtine retard led to a significant improvement in all measured muscle-specific indicators: pain pressure threshold (+48%), pain pressure tolerance (+27%) and depth of penetration in the muscle (+18%) (all values p