Pregabalin exerts a range of effects in pain transmission and although the precise mechanism of action is not completely understood, it likely involves the binding of the drug to calcium channels in the central nervous system (Ben-Menachem 2004). In animal experiments it has been shown that pregabalin primarily exerts its effect in the dorsal horn, where a reduced pain signal is seen. Pregabalin is a ligand of the α2-δ subunit of the voltage-gated calcium channel and binding of pregabalin to this site results in reduced calcium influx at the nerve terminals and therefore a reduced release of several excitatory neurotransmitters, including glutamate, substance P (SP), calcitonin-gene related peptide (CGRP) and noradrenaline. This may result in inhibition or reduction of the sensitization mentioned above. Moreover, this may be the basis for the analgesic effect. It has been shown, in animal experiments, that binding of pregabalin to calcium channels is able to counteract central sensitization in the dorsal horn.