Eperisone (full name: eperisone hydrochloride) is an antispasmodic drug, sold in Japan, India, The Philippines and Bangladesh under the brand name Myonal. Eperisone acts by relaxing both skeletal muscles and vascular smooth muscles, and demonstrates a variety of effects such as reduction of myotonia, improvement of circulation, and suppression of the pain reflex. The drug inhibits the vicious cycle of myotonia by decreasing pain, ischaemia, and hypertonia in skeletal muscles, thus alleviating stiffness and spasticity, and facilitating muscle movement.
Eperisone also improves dizziness and tinnitus associated with cerebrovascular disorders or cervical spondylosis.
Eperisone has a relatively low incidence of sedation when compared with other anti-spasmodic drugs; this simplifies the clinical application of the drug and makes it an attractive choice for patients who require anti-spasmodic therapy without a reduction in alertness.
Eperisone also facilitates voluntary movement of the upper and lower extremities without reducing muscle power; it is therefore useful during the initial stage of rehabilitation and as a supporting drug during subsequent rehabilitative therapy.