Lupin’s Namuscla® (mexiletine) is recommended by NICE for treatment of symptomatic myotonia in adults with non-dystrophic myotonic disorders (NDM)


Lupin’s Namuscla® (mexiletine) is recommended by NICE for treatment of symptomatic myotonia in adults with non-dystrophic myotonic disorders (NDM)

Slough, UK, 4 November 2021: Global pharma major Lupin today announces that the National Institute for Health and Care Excellence (NICE) has issued the Final Appraisal Determination (FAD) recommending the routine funding of Namuscla (mexiletine) in England and Wales.1 NICE recommends Namuscla (mexiletine) within its marketing authorisation, as an option for treating the symptoms of myotonia in adults with non-dystrophic myotonic disorders. Lupin has agreed a confidential patient access scheme with NHS England (NHSE). 1

NDM is a group of rare genetic neuromuscular disorders caused by mutations in sodium or chloride ion channels, 2 affecting approximately 400 patients in England. 3 Clinically, NDM manifests with myotonia, a muscle stiffness which makes it difficult to perform daily activities. Myotonia can severely affect different parts of the body with pain, weakness and fatigue being the main symptoms, among others, that accompany the disease.2

Namuscla is licensed in the European Union and the UK for the symptomatic treatment of myotonia in adults with NDM.4

“We are delighted that NDM patients in England and Wales will be able to access Namuscla. We are grateful to patients, their caregivers and all the healthcare professionals involved in the NICE process. The decision by NICE is a significant step forward for patients with rare disease as well as for repurposing medicines,” said Ben Ellis, General Manager of Lupin Healthcare UK. “Lupin’s transformational journey into specialty disease areas continues, with future investments planned for neuromuscular diseases, to meet unmet patient need.”

Lupin provided comprehensive data to support the NICE submission, demonstrating the efficacy and long-term safety of Namuscla and the significant improvements in the quality of life for NDM patients.4 Supporting evidence included three randomised controlled studies 4-6 and two retrospective long-term studies.7,8

For further information or media enquiries please contact:

Consilium Strategic Communications
Sukaina Virji
Tel: +44 (0)7738 499212

Notes for Editors

About Non-Dystrophic Myotonias (NDM)
Non-dystrophic myotonias (NDM) are a heterogenous group of rare neuromuscular disorders caused by mutations within ion channels in the sarcolemma membrane of skeletal muscles and affects 1 in 100,000 people.2 Non-dystrophic myotonias exhibit both sodium and chloride channelopathies which result in altered membrane excitability. The major clinical manifestation of the non-dystrophic myotonias is muscle stiffness as a consequence of the myotonia-delayed muscle relaxation after voluntary contraction. Myotonia can severely affect different parts of the body, with pain, weakness and fatigue being the main symptoms, among others, that accompany the disease. 2

Myotonia in NDM patients has an onset in childhood and it persists throughout a patient’s life. Although not life limiting, patients with non-dystrophic myotonia can experience significant lifetime morbidity due to stiffness and pain related to myotonia. Patients may perceive that myotonia increases in severity over time, impacting daily life. 9 Myotonia is described by patients in a variety of ways (stiffness, cramps, pain, difficulty releasing a fist, or difficulty swallowing or eating) which can contribute to substantial delays in diagnosis and treatment, leading to decreased patient quality-of-life and often significant disability.10

About mexiletine
In randomised controlled trials 4-6 mexiletine has been shown to significantly reduce myotonia compared to placebo in adult patients with NDM, reducing skeletal muscle hyperexcitability through its use-dependent, voltage-gated, sodium channel blocking actions which are independent of the cause of channel function. This resulted in an improvement in patient quality-of-life and other functional outcomes. The most commonly reported adverse reactions in patients treated with mexiletine are abdominal pain (12%), vertigo (8%) and insomnia (12%),4 demonstrating mexiletine is generally well-tolerated. 5-7

About Lupin
Lupin is an innovation-led transnational pharmaceutical company headquartered in Mumbai, India. The Company develops and commercialises a wide range of branded and generic formulations, biotechnology products and APIs in over 100 markets in the U.S, India, South Africa and across Asia Pacific (APAC), Latin America (LATAM), Europe and Middle-East regions. 11

The Company enjoys leadership position in the cardiovascular, anti-diabetic, and respiratory segments and has significant presence in the anti-infective, gastro-intestinal (GI), central nervous system (CNS) and women’s health areas. Lupin is the third largest pharmaceutical company in the U.S. by prescriptions. 11

Lupin has 15 manufacturing sites, 7 research centres, more than 20,000 professionals working globally, 11 and has been consistently recognised as a 'Great Place to Work' in the Biotechnology & Pharmaceuticals sector.12


  1. NICE Final Appraisal Document: Mexiletine for treating myotonia in adults with non-dystrophic myotonic disorders. Nov 2021.
  2. Matthews E, Fialho D, Tan SV, et al. The non-dystrophic myotonias: molecular pathogenesis, diagnosis and treatment. Brain 2010:133; 9–22.
  3. Horga A, Raja Rayan DL, Matthews E, et al. Prevalence study of genetically defined skeletal muscle channelopathies in England. Neurology. 2013;80(16):1472-5
  4. Namuscla - Summary of Product Characteristics. Available at [Accessed 03 Nov 2021]
  5. Statland JM, Bundy BN, Wang Y, et al. Consortium for Clinical Investigation of Neurologic Channelopathies. Mexiletine for symptoms and signs of myotonia in nondystrophic myotonia: a randomized controlled trial. JAMA. 2012;308(13):1357–1365.
  6. Stunnenberg BC, Raaphorst J, Groenewoud HM et al. Effect of mexiletine on muscle stiffness in patients with nondystrophic myotonia evaluated using aggregated N-of-1 trials. JAMA. 2018;320:2344-2353
  7. Suetterlin  KJ, Bugiardini  E, Kaski  JP,  et al.  Long-term safety and efficacy of mexiletine for patients with skeletal muscle channelopathies.  JAMA. Neurol. 2015;72(12):1531-1533.
  8. Lupin Limited. Long term follow up data from MYOMEX - EMA response Q13 Annex. LUP-NAM-065. Data on file. 2019.
  9. Trip J, Drost G, Ginjaar HB, et al. Redefining the clinical phenotypes of non-dystrophic myotonic syndromes. J Neurol Neurosurg Psychiatry. 2009;80:647–652. 
  10. Trivedi JR, Bundy B, Statland J, et al; CINCH Consortium. Non-dystrophic myotonia: prospective study of objective and patient reported outcomes. Brain. 2013;136:2189-2200.
  11. Lupin Healthcare UK Limited: Lupin’s Global Presence. Available at [Accessed Online: 03 Nov 2021]
  12. Great Place to Work®. Available at [Accessed on 03 November 2021]



Namuscla Summary of Product Characteristics SPC Accessed Nov 2021