טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentShefi Tom
SubjectPregabalin and Carbamazepine's Analgesic Effect Over
Persistent Pain, in the Formalin Test
DepartmentDepartment of Medicine
Supervisors Professor Yitzhak Schiller
Professor David Yarnitsky


Abstract

Analgesic treatment of persistent neuropathic pain is currently conducted in a trial and error manner. The algorithm currently in use dictates usage of first line drugs (antidepressants or anticonvulsants), reassessment, and continuation or alteration of the treatment. The drugs are chosen based on the possible effects of either drugs on the patient’s quality of life rather than their mechanism of action. If we understand how certain analgesics work in relation to the pathogenesis of the persistent pain, we may be able to predict which drug will be more efficient in any given scenario. The formalin test can be separated to two distinct phases the early and late phase. Each phase is caused by a different mechanism. We will focus on the late phase, which is considered a persistent pain, and shares various similarities with neuropathic and inflammatory pain. Anticonvulsants are a known analgesic drug for the chronic treatment of neuropathic and neuralgic pain. They are widely utilized as a first line drugs in various scenarios, from diabetic neuropathy, to post-operative pain as well as other neuropathic nociceptive insults. Their mechanism of action usually acts on the CNS, which is why they aren't widely utilized as an acute analgesic for peripheral inflammatory pain. In this research project we tested the analgesic effects of two specific 2 anticonvulsants widely used for treating neuropathic and neuralgic pain, namely pregabalin and carbamazepine in the mouse formalin test. Our results show that compared to a control group, pregabalin did have a significant analgesic effect on the late phase of the formalin test, both in the strength and the temporal profile of the reaction. In contrast, carbamazepine did not have any significant effects compared to the control group. These findings stress the different analgesic effects of pregabalin and carbamazepine.