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amifampridine

Firdapse (previously Zenas) · ATC code N07XX05

Also known as: Amifampridin · Brand names: Firdapse, Amifampridin Accord, Amifampridin Amarox, Amifampridin Axunio, Amifampridin Hormosan, Amifampridin Puren

Key facts
Active substance
amifampridine
ATC code
N07XX05
Authorisation
centrally authorised across the EU (EMA)
Dosage forms
FIRDAPSE 10 mg tablets
Marketing authorisation holder
SERB SA
Information as of
2026-10-28

Key facts

Amifampridine is a potassium channel blocker. It is used for the symptomatic treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults.

What it is used for

  • Symptomatic treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults (Firdapse).

Dosing

  • Given in divided doses three or four times a day, with food; started under supervision of a physician experienced in the disease.
  • Starting dose 15 mg a day; increase in 5 mg increments every 4 to 5 days to a maximum of 60 mg per day. No single dose should exceed 20 mg.
  • Moderate or severe renal or hepatic impairment: starting dose 5 mg (half tablet) once daily; mild impairment: 10 mg per day (5 mg twice a day). Titrate more slowly in 5 mg increments every 7 days; stop up-titration if an adverse reaction occurs.
  • Children and adolescents: safety and efficacy not established.

Contraindications

  • Hypersensitivity to the active substance or any of the excipients.
  • Epilepsy; uncontrolled asthma.
  • Concomitant use of sultopride, of medicines with a narrow therapeutic window, or of medicines known to cause QTc prolongation.
  • Congenital QT syndromes.

Important warnings

  • Renal or hepatic impairment: risk of markedly increased exposure; careful monitoring and slower titration.
  • Increased, dose-dependent risk of epileptic seizures, especially with factors that lower the seizure threshold; stop treatment if a seizure occurs.
  • Benign and malignant Schwannomas occurred in a rat carcinogenicity study; relevance to humans is unknown.
  • LEMS symptoms may return after discontinuation.

Side effects

  • Most common: paraesthesias (e.g. peripheral and around the mouth) and gastrointestinal disorders (epigastralgia, diarrhoea, nausea, abdominal pain); intensity and incidence are mostly dose-dependent.
  • Very common: dizziness, hypoaesthesia, paraesthesia; common: cold extremities.
  • Frequency unknown: convulsions, chorea, myoclonia, sleep disorders, anxiety, blurred vision, cardiac rhythm disorders, palpitations, Raynaud's syndrome.

Interactions

  • Sultopride and other QT-prolonging medicines (e.g. disopyramide, cisapride, domperidone, rifampicin, ketoconazole) are contraindicated (risk of torsade de pointes).
  • Substances that lower the seizure threshold (e.g. most antidepressants) increase the risk of seizures.
  • Monitor for adverse reactions when starting a potent enzyme or renal transporter inhibitor.

Pregnancy and breastfeeding

  • Firdapse should not be used during pregnancy; women of childbearing potential must use effective contraception.
  • Breast-feeding: see the full text.

Summary of the official product information, written with AI on 2026-10-29. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

Common questions – ask Medelix

For patients

Package leaflet, verbatim

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

EU – centrally authorised (all member states)

Source: European Medicines Agency (EMA), product information

Germany

  • Amifampridin AccordAccord Healthcare B.V. · 1 register entry
  • Amifampridin AmaroxAmarox Pharma Gmbh · 1 register entry
  • Amifampridin AxunioAxunio Pharma Gmbh · 1 register entry
  • Amifampridin HormosanHormosan Pharma Gmbh · 1 register entry
  • Amifampridin PurenPuren Pharma Gmbh & Co. Kg · 2 register entries

Source: EMA – Article 57 product data (EU/EEA), as of 2026-10-29

Brand names in 10 more European countries
France
Amifampridine Amarox, Amifampridine Biogaran, Amifampridine Substipharm
Hungary
Amifampridine Accord
Iceland
Amifampridine Serb, Firdapse
Italy
Amifampridina Accord, Amifampridina Amarox
Liechtenstein
Amifampridine Serb, Firdapse
Netherlands
Amifampridine Accord, Amifampridine Amarox, Amifampridine Xiromed
Norway
Amifampridin Medical Valley, Amifampridine Accord, Amifampridine Serb, Firdapse
Poland
Amifampridine Medical Valley
Portugal
Amifampridina Accord, Amifampridina Generis, Zevrion
Slovenia
Amifampridin Accord

EMA – Article 57 product data (EU/EEA), 2026-10-29

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

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Sources

  1. European Medicines Agency. Firdapse (previously Zenas) – EPAR, Product Information. 2026-10-28. https://www.ema.europa.eu/en/documents/product-information/firdapse-epar-product-information_en.pdf
  2. EMA – Article 57 product data (EU/EEA), 2026-10-29. https://www.ema.europa.eu/en/human-regulatory-overview/post-authorisation/data-medicines-iso-idmp-standards-post-authorisation/public-data-article-57-database

Editorial: Medelix editorial team · last updated 2026-10-28 · How these pages are made · Report an error

Source: European Medicines Agency (EMA), product information. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.