Spasmolytics

The generation of the neuronal signals that cause muscle contractions are dependent on the balance of synaptic excitation and inhibition that the neuron receives. Centrally acting muscle relaxants enhance the level of inhibition by either mimicking or enhancing the actions of endogenous inhibitory substances like GABA. These muscle relaxants may act at the level of the cortex, brain stem or spinal cord; or most likely all three. Because of the enhancement of inhibition in the CNS, most centrally acting muscle relaxants have the side-effects of sedation, drowsiness and may cause dependence with long term use. Several centrally acting muscle relaxants are also drugs of abuse, and their prescription is strictly controlled.