Fluoxetine maleate is a selective neurogenic potassium channel opener. It is easy to be absorbed orally. It has the triple effects of analgesia, muscle relaxation and neuroprotection. It has analgesic effect on pain caused by many reasons. It has no affinity with opioid receptors and does not inhibit the synthesis of chemical Book prostaglandins. It is not antagonized by naloxone. The analgesic intensity (ED50) is weaker than methadone, buprenorphine and morphine, about 50% of morphine, equivalent to pentazocine, and stronger than pethidine, codeine, phenacetin and paracetamol.