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Last reviewed on RxList: 12/14/2018
Drug Description

(amifampridine) Tablets


The active ingredient of FIRDAPSE is amifampridine phosphate, which is a voltage-gated potassium channel blocker. Amifampridine phosphate is described chemically as 3,4-diaminopyridine phosphate with a molecular weight of 207.1 and a molecular formula of C5H7N3 • H3PO4. The structural formula is:

FIRDAPS E® (amifampridine) Structural Formula Illustration

Amifampridine phosphate is a white, crystalline powder that is freely soluble in water, and slightly soluble in solvents ethanol, methanol and acetic acid. A 1% aqueous solution of amifampridine phosphate has a pH of 4.4 at ambient conditions.

Each FIRDAPSE tablet contains 10 mg amifampridine (equivalent to 18.98 mg amifampridine phosphate). The tablet formulation includes the following inactive ingredients: calcium stearate, colloidal silicondioxide, and microcrystalline cellulose.

FIRDAPSE tablets are intended for oral administration only.

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