|AMPYRA (dalfampridine) is a potassium channel blocker, available in a 10 mg tablet strength. Each tablet contains 10 mg dalfampridine, formulated as an extended release tablet for twice-daily oral administration. Dalfampridine is also known by its chemical name, 4-aminopyridine.|
| Mechanism of action
The mechanism by which dalfampridine exerts its therapeutic effect has not been fully elucidated. Dalfampridine is a broad spectrum potassium channel blocker. In animal studies, dalfampridine has been shown to increase conduction of action potentials in demyelinated axons through inhibition of potassium channels.
Dalfampridine is largely unbound to plasma proteins (97-99%). The apparent volume of distribution is 2.6 L/kg.
There is no apparent difference in pharmacokinetic parameter values following administration of AMPYRA tablets to either healthy volunteers or patients with MS.
When dalfampridine is taken with food, there is a slight increase in Cmax (12-17%) and a slight decrease in AUC (4-7%). These changes in exposure are not clinically significant, and therefore the drug may be taken with or without food [see Dosage and Administration].
Metabolism and Elimination:
The elimination half-life of dalfampridine following administration of the extended release tablet formulation of AMPYRA is 5.2 to 6.5 hours. The plasma half-life of the sulfate conjugate is approximately 7.6 hours and the half-life of 3-hydroxy-4-aminopyridine could not be calculated because concentrations for most subjects were close to or below the limit of quantitation.
In vitro studies with human liver microsomes indicate that CYP2E1 was the major enzyme responsible for the 3-hydroxylation of dalfampridine. The identity of the CYP enzymes suspected of playing a minor role in the 3-hydroxylation of dalfampridine could not be established unequivocally
Indications and usage
|AMPYRA™ (dalfampridine) is a potassium channel blocker indicated to improve walking in patients with multiple sclerosis (MS). This was demonstrated by an increase in walking speed|
| WARNINGS AND PRECAUTIONS
Seizures: AMPYRA can cause seizures; the risk of seizures increases with increasing AMPYRA doses; AMPYRA is contraindicated in patients with a prior history of seizure; discontinue AMPYRA use if seizure occurs.
Renally impaired patients: AMPYRA is contraindicated in patients with moderate or severe renal impairment (CrCl≤50 mL/min); the risk of seizures in patients with mild renal impairment (CrCl 51-80 mL/min) is unknown, but AMPYRA plasma levels in these patients may approach those seen at a dose of 15 mg twice daily, a dose that may be associated with an increased risk of seizures; estimated CrCl should be known before initiating treatment with AMPYRA.
AMPYRA should not be taken with other forms of 4-aminopyridine (4-AP, fampridine), since the active ingredient is the same.
Nursing Mothers: Discontinue drug or nursing taking into consideration importance of drug to mother.
Renal Impairment: Clearance of dalfampridine is decreased in patients with renal impairment; AMPYRA is contraindicated in patients with moderate or severe renal impairment (CrCl≤50 mL/min); AMPYRA plasma levels in patients with mild renal impairment (CrCl 51-80 mL/min) may approach those seen at a dose of 15 mg twice daily, a dose which may be associated with an increased risk of seizures.
Geriatric use: Because elderly patients are more likely to have decreased renal function, it is particularly important to know the estimated CrCl in these patients before initiating AMPYRA treatment
|The most common adverse events (incidence ≥2% and at a rate greater than the placebo rate) for AMPYRA in MS patients were urinary tract infection, insomnia, dizziness, headache, nausea, asthenia, back pain, balance disorder, multiple sclerosis relapse, paresthesia, nasopharyngitis, constipation, dyspepsia, and pharyngolaryngeal pain.|
Dosage and administration
| Maximum recommended dose: 10 mg twice daily (approximately 12 hours apart) with or without food.
Patients should not take double or extra doses if a dose is missed. No additional benefit was demonstrated at doses greater than 10 mg twice daily and adverse events, including seizures, were more frequent at higher doses.
Tablets should only be taken whole; do not divide, crush, chew, or dissolve.
Renal impairment: AMPYRA is contraindicated in patients with moderate or severe renal impairment; the risk of seizures in patients with mild renal impairment is unknown, but AMPYRA plasma levels in these patients may approach those seen at a dose of 15 mg twice daily, a dose that may be associated with an increased risk of seizures.
| MPYRA (dalfampridine) extended release tablets, 10 mg are a film-coated, white to off-white, biconvex, oval shaped, non-scored tablets with flat edge. The tablets are identified by a debossed code "A10" on one side and are available in bottles of 60.
NDC 10144-427-60 bottles of 60 tablets
Store at 25°C (77°F). Excursions permitted 15-30ºC (59-86ºF).
| Package Insert data.
Distributed by: Acorda Therapeutics, Inc.
AMPYRA™ is a trademark of Acorda Therapeutics, Inc.
National Institutes of Health, U.S. National Library of Medicine, DailyMed Database.
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