A large number of the injections that we use for pain include local anaesthetics. These work by reducing the electric charge conduction along nerves, thus reducing sensation and the ability of the nerves to make muscles contract.
There is evidence that temporarily blocking painful nerve pathways can on occasions give pain relief of considerably longer duration than the expected action of the local anaesthetic. This may work by mechanisms including "resetting" of sensitised pain mechanisms in the spinal cord or brain.
The local anaesthetics that we use belong to the Amide group of drugs, including lignocaine (which is also often used by dentists) and bupivacaine, which lasts substantially longer than lignocaine.
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Pain Service Website, Gloucestershire Hospitals NHS Foundation Trust
Webmaster Dr J G de Courcy, Consultant in Pain Medicine and Anaesthesia
Page updated 19/02/2016