Alendronate induces antinociception in mice, not related with its effects in bone

The antinociceptive effect of alendronate was studied. The bisphosphonate w as i.p. administered and two tests were carried out: acetic acid in mice an d formalin test in rats. In the acetic acid test, alendronate induced a dos e-dependent antinociceptive effect that was statistically significant for t he doses of 10, 20 and 40 mg/kg, and could be detected 48 hr after its admi nistration. In the formalin test, however, alendronate, at the doses of 10 and 20 mg/kg, did not modify the pain score nor the number of flinches, whe n it was administered either 30 or 60 min before the test. However it must be noted that doses inducing analgesic effect are close to those inducing t oxicity.