Anaphylaxis caused by muscle relaxant (eperisone hydrochloride)

ABSTRACT

Eperisone hydrochloride is an antispasmodic drug, decreasing spasticity of skeletal muscle and alleviating stiffness, and as a consequence, controlling pain. It is preferably prescribed with other analgesics, beneficially less decreasing alertness compared with other antispasmodics. Its fatal drug adverse reactions were rarely reported. A 70 year-old female with hives, swollen face, hoarse voice, and near fainting admitted via emergency department. She suffered from the series of the fatal symptoms after administration of the pills, prescribed for her neck pain. Two months before, she had experienced hives on similar medications. At presentation, she revealed hypoxemia and hypotension, and treated with epinephrine, glucocorticoids and antihistamines. Among the medicines she took, eperisone hydrochloride was proven as the causative medicine and others were excluded in oral provocation tests. The positive result in intradermal test with eperisone hydrochloride suggested immediate-type hypersensitivity reaction. We report a case of anaphylaxis to eperisone hydrochloride, one of the widely prescribed medicines in clinical practice, previously without awareness of drug adverse reaction.