Medical Information Only: This medication is not sold on this site. The information provided is for reference purposes only. Please consult your local physician or pharmacist for treatment.

amifampridine phosphate (Firdapse): Dosing and Uses

 

Classes: Potassium Channel Blockers

Medically reviewed by Min Clinic Staff | Updated: January 2026

Dosing and uses of Firdapse (amifampridine phosphate)

 

Lambert-Eaton Myasthenic Syndrome (LEMS)

Pending FDA approval for symptomatic treatment of LEMS in adults

 

Myasthenia Gravis (Orphan)

Orphan designation for treatment of myasthenia gravis

Sponsor

  • Catalyst Pharmaceuticals, Inc; 355 Alhambra Circle Suite 1250; Coral Gables, Florida 33134

 

Pediatric dosage forms and strengths

 

Congenital Myasthenic Syndromes (Orphan)

Orphan designation for treatment of congenital myasthenic syndromes

Sponsor

  • Catalyst Pharmaceuticals, Inc; Suite 1500; Coral Gables, Florida 33134

 

Pharmacology of Firdapse (amifampridine phosphate)

Mechanism of action

Blocks voltage-dependent potassium channels, thereby prolonging presynaptic cell membrane depolarization which enhances calcium transport into nerve-endings

The increased intracellular calcium concentrations facilitate exocytosis of acetylcholine-containing vesicles, which in turn enhances neuromuscular transmission