Antinociceptive effects of cefadroxil and ceftriaxone in experimental animal models of pain

BACKGROUND: As an "off-target" effect, cephalosporins can enhance glutamate transporter-1 expression in astrocytes to recycle glutamate from synaptic cleft, and exhibited analgesic properties in animals and humans with chronic pain. METHODS: In the present study, we focused on making a side-by-side comparison of the analgesic potentials of cefadroxil and ceftriaxone, using rodent models of peripheral neuropathic pain, inflammatory pain and incisional pain. Microdialysis technique was adopted to validate the in vivo glutamate regulatory properties of these two drugs in central nervous system. RESULTS: We have shown that cefadroxil and ceftriaxone are beneficial in a variety of pain scenarios, without inducing observable side effects. The two cephalosporins worked better on neuropathic pain, rather than inflammatory pain or incisional pain, suggesting nociceptive system was differentially affected. Further, microdialysis has confirmed that cephalosporins can effectively reverse the elevated levels of glutamate in brain of animals with neuropathic pain. CONCLUSIONS: The outcome of this study may guide us to identify a molecular skeleton derived from cefadroxil, based on which we could possibly develop new non-antibiotic analgesic compounds with glutamate recycling properties.