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Open‐label trial of ranolazine for the treatment of paramyotonia congenita
Author(s) -
Lorusso Samantha,
Kline David,
Bartlett Amy,
Freimer Miriam,
Agriesti Julie,
Hawash Ahmed A.,
Rich Mark M.,
Kissel John T.,
David Arnold W.
Publication year - 2019
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.26372
Subject(s) - ranolazine , myotonia , tolerability , medicine , placebo , sodium channel blocker , myotonia congenita , electromyography , anesthesia , channelopathy , adverse effect , sodium channel , physical medicine and rehabilitation , sodium , chemistry , myotonic dystrophy , pathology , alternative medicine , organic chemistry
Paramyotonia congenita (PMC) is a nondystrophic myotonic disorder that is believed to be caused by a defect in Na v 1.4 sodium channel inactivation. Ranolazine, which acts by enhancing slow inactivation of sodium channels, has been proposed as a therapeutic option, but in vivo studies are lacking. Methods We conducted an open‐label, single‐center trial of ranolazine to evaluate efficacy and tolerability in patients with PMC. Subjective symptoms of stiffness, weakness, and pain as well as clinical and electrical myotonia were evaluated. Baseline measures were compared with those after 4 weeks of treatment with ranolazine. Results Ranolazine was tolerated well without any serious adverse events. Both subjective symptoms and clinical myotonia were significantly improved. Duration of myotonia was reduced according to electromyography, but this change was not statistically significant in all tested muscles. Discussion Our findings support the use of ranolazine as a treatment for myotonia in PMC and suggest that a randomized, placebo‐controlled trial is warranted. Muscle Nerve 59 :240–243, 2019