Products
Amifampridine is commercially available in tablet form (Firdapse). It has been approved in many countries since 2012.
Structure and properties
Amifampridine (C5H7N3, Mr = 109.1 g/mol) is present in drugs as amifampridine phosphate. It is the pyridine derivative 3,4-diaminopyridine. Amifampridine is structurally closely related to fampridine (4-aminopyridine), which is also commercially available.
Effects
Amifampridine (ATC N07XX05) blocks voltage-gated potassium channels, resulting in increased intracellular calcium concentration, increased exocytosis of acetylcholine-containing vesicles, and increased neuromuscular transmission. It thereby improves muscle strength.
Indications
Symptomatic treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults. This is a rare autoimmune disease that targets voltage-gated calcium channels and results in muscle weakness.
Dosage
According to the package insert. Tablets are taken three to four times daily with meals.
Adverse effects
The most common possible adverse effects include sensory disturbances and digestive symptoms such as stomach pain, diarrhea, nausea, and abdominal pain.
