Efficacy of Duloxetine, a Potent and Balanced Serotonergic and Noradrenergic Reuptake Inhibitor, in Inflammatory and Acute Pain Models in Rodents

• DOI: 10.1124/jpet.104.075960
• Publication Date: 2005-01-15T01:38:26Z
• Authors: Carrie K. Jones; Steven C. Peters; Harlan E. Shannon
• Keywords: Inflammation; Male; Analgesics; Hot Temperature; Adrenergic Uptake Inhibitors; Cyclohexanecarboxylic Acids; Dose-Response Relationship, Drug; Morphine; Anti-Inflammatory Agents, Non-Steroidal; Ibuprofen; Carrageenan; Duloxetine Hydrochloride; 3. Good health; Analgesics, Opioid; Mice; 03 medical and health sciences; 0302 clinical medicine; Hyperalgesia; Animals; Amines; Capsaicin; Gabapentin; Excitatory Amino Acid Antagonists

Duloxetine, a selective but balanced serotonergic and noradrenergic reuptake inhibitor, was evaluated in the acute nociceptive pain models of tail flick and hot plate in mice and in the persistent and/or inflammatory pain models of acetic acid-induced writhing in mice, carrageenan-induced thermal hyperalgesia and mechanical allodynia in rats, and capsaicin-induced mechanical allodynia in rats. In acute pain models, duloxetine had no significant effect on response latency in the mouse tail-flick test but produced modest increases in response latencies in the mouse hot plate test. Morphine produced dose-related analgesic effects in both the mouse tail-flick and hot plate tests. In models of inflammatory and/or persistent pain, duloxetine, morphine, and ibuprofen produced dose-related decreases in acetic acid-induced writhing in mice. Duloxetine, ibuprofen, and gabapentin also produced dose-dependent reversals of both thermal hyperalgesia and mechanical allodynia produced by carrageenan in rats. In addition, both duloxetine and morphine produced a significant reduction of capsaicin-induced mechanical allodynia in rats. Duloxetine and gabapentin were without substantial effect on the Rotorod test in mice, whereas morphine and ibuprofen produced a significant impairment. Our data indicate that duloxetine may be efficacious in the treatment of persistent and/or inflammatory pain states at doses that have modest or no effect on acute nociception or motor performance.