Bruxism secondary to antipsychotic drug exposure: a positive response to propranolol.

We present two cases of acute nocturnal bruxism occurring as an early side effect of antipsychotic drug treatment. The development of bruxism was coupled with the appearance of neuroleptic-induced akathisia. Both complications were relieved after the beta-adrenergic blocker propranolol was added, suggesting the involvement of the adrenergic and serotonergic central nervous systems, besides the dopaminergic system, in the pathogenesis of bruxism. The positive response of iatrogenic bruxism to propranolol implies that propranolol also deserves a trial for the treatment of noniatrogenic nocturnal bruxism.