Injectable supersaturated acetaminophen solution for spinal administration

Abstract

The present invention relates to an acetaminophen injectable aqueous solution for use in the treatment or in the prevention of pain by spinal administration, wherein said acetaminophen injectable solution is supersaturated. In certain embodiments, the acetaminophen injectable aqueous solution is administered simultaneously, separately or sequentially with a local anaesthetic by spinal administration.

1 - 11 . (canceled) 
     
     
         12 . A method of providing analgesia comprising:
 spinally administering a stable acetaminophen supersaturated injectable aqueous solution, wherein said supersaturated injectable aqueous solution comprises a solvent which is degassed or substantially oxygen or air free and comprises acetaminophen in a concentration greater than 1.8 w/v.   
     
     
         13 . The method according to  claim 12 , wherein the acetaminophen concentration is ranging from 1.8 to 8.0% w/v. 
     
     
         14 . The method according to  claim 12  wherein said injectable aqueous solution is substantially free of preservatives, and/or additives and/or co-solvents. 
     
     
         15 . The method according to  claim 12 , obtained by degassing water by a flow of an inert gas and by dissolving acetaminophen therein in an amount to give a supersaturated solution. 
     
     
         16 . The method according to  claim 12  in the treatment of post-surgical pain. 
     
     
         17 . The method according to  claim 12  further comprising the simultaneous, separate or sequential spinal administration with a local anaesthetic. 
     
     
         18 . The method according to  claim 17  wherein the acetaminophen solution is added to or mixed with a solution of a local anaesthetic for spinal administration. 
     
     
         19 . The method according to  claim 17  wherein said local anaesthetic is a short-acting local anaesthetic selected from lidocaine, articaine, oxybuprocaine, chloroprocaine or a medium-acting local anaesthetic selected from prilocaine, mepivacaine, etidocaine or a long-acting local anaesthetic selected from ropivacaine, bupivacaine, cinchocaine, levobupivacaine, proxymetacaine, tetracaine. 
     
     
         20 . The method according to  claim 17  for the combined analgesic-anaesthetic treatment. 
     
     
         21 . The method according to  claim 17  wherein the analgesic effect of acetaminophen has a longer duration than the analgesic effect of the local anaesthetic. 
     
     
         22 . The method according to  claim 17  wherein the local anaesthetic and acetaminophen exert an analgesic effect even after the end of the anaesthetic effect caused by the local anaesthetic.