Analgesic composition and method

Abstract

A pharmaceutical analgesic composition comprising an opioid analgesic agent and a compound that binds to the SS 1 or SS 2 subunit of a sodium channel, such as tetrodotoxin and saxitoxin, and analogs thereof. Administration of an opioid analgesic agent and a compound that binds to the SS 1 or SS 2 subunit of a sodium channel, such as tetrodotoxin and saxitoxin, and analogs thereof, produces analgesia in the treatment of pain in mammals.

We claim:  
     
         1 . A pharmaceutical composition comprising an opioid and a sodium channel blocker that specifically binds to the SS1 or SS2 subunit of a sodium channel and a pharmaceutically acceptable carrier.  
     
     
         2 . The pharmaceutical composition of  claim 1 , wherein the sodium channel blocker is tetrodotoxin represented by the formula I below:  
       
         
           
           
               
               
           
         
       
     
     
         3 . The pharmaceutical composition of  claim 1 , wherein the sodium channel blocker is saxitoxin represented by the formula II below:  
       
         
           
           
               
               
           
         
       
     
     
         4 . The pharmaceutical composition of  claim 1 , wherein the opioid is selected from the group consisting of morphine, codeine, methadone and fentanyl.  
     
     
         5 . The pharmaceutical composition of  claim 2 , wherein the opioid is selected from the group consisting of morphine, codeine, methadone and fentanyl.  
     
     
         6 . The pharmaceutical composition of  claim 1 , wherein the sodium channel blocker and the opioid are present in a ratio by weight of from 1:100 to 1:30,000.