Ampyra (dalfampridine)
Last reviewed · Source: First Databank (FDB) drug data
Overview
Dalfampridine (formerly known as fampridine (4-aminopyridine, 4-AP)) is a broad spectrum potassium channel blocker.
Dalfampridine in an aminopyridine and is a broad spectrum potassium channel blocker.
Dalfampridine was formerly known as fampridine (4-aminopyridine; 4-AP), and is commercially available as extended-release (ER) tablets. The drug has been prepared extemporaneously as immediate-release capsules or oral solution.
Dalfampridine has a relatively narrow therapeutic index with concentration-dependent adverse effects. Compared with the immediate-release preparations, commercially available extended-release dalfampridine tablets provide an improved pharmacokinetic profile (e.g., lower peak plasma concentrations, more stable and sustained plasma concentrations) and allow use of a twice-daily dosage regimen.
The mechanism of action responsible for improved walking in MS patients receiving dalfampridine has not been fully elucidated. The drug selectively blocks fast, voltage-gated potassium channels (Kv) in excitable tissues and nonexcitable cells such as B cells and T lymphocytes. In vitro and animal studies indicate increased conduction of action potentials in demyelinated axons; this effect appears to be dose dependent.
Other mechanisms of action (e.g., potentiation of synaptic transmission and skeletal muscle twitch tension, immunomodulatory effects on Kv channels in microglia, macrophages, dendritic cells, and/or T lymphocytes) may also be involved.
Dalfampridine administered orally is completely and rapidly absorbed from the GI tract. The relative bioavailability of the extended-release tablet is 96% when compared to an aqueous oral solution. Compared to the oral solution, absorption of the extended-release tablet is delayed and peak plasma concentrations are lower, but AUC is not altered.
Administration of dalfampridine with food does not affect the pharmacokinetics to a clinically important extent. Peak plasma concentrations with extended-release dalfampridine are achieved between 3-4 hours post-dose. Dalfampridine is mostly unbound to plasma proteins (97-99%).
Following oral administration, 95.9% of a dalfampridine dose is eliminated in urine and 0.5% is eliminated in feces. The elimination half-life of the extended-release tablet following oral administration is 5.2-6.5 hours.
Dalfampridine does not prolong the QTc interval and does not have a clinically important effect on QRS duration.
USES: Dalfampridine is used to improve walking in people with multiple sclerosis (MS). It is a potassium channel blocker. It is thought to work by improving nerve conduction.
Generic name: dalfampridine
Pronunciation: (dal-FAM-pri-deen)
Reference product & biosimilars
No reference, biosimilar or interchangeable associated with this drug.
Today’s intelligence on Ampyra
Indications
The following indications are listed for Ampyra:
- Walking Impairment Due To Multiple Sclerosis
Also known as: Walking Disability Due To Multiple Sclerosis.
Dosing
No dosing information is available for this tab.
Dalfampridine is administered orally as an extended-release tablet. The drug may be given with or without food.
Dalfampridine doses should be taken approximately 12 hours apart.
The extended-release tablets should be swallowed whole and should not be divided, crushed, chewed, or dissolved.
Store dalfampridine extended-release tablets at 25degreesC; excursions are permitted to 15-30degreesC.
If a dose is missed, patients should not double the dose or take extra doses. The next dose should be taken at the regularly scheduled time.
No dosing information is available for this tab.
No dosing information is available for this tab.
Drug interactions
Dalfampridine is metabolized by cytochrome P-450 (CYP) isoenzyme 2E1 and, possibly, other unidentified CYP isoenzymes.
There are no contraindication interactions for this drug.
There are no severe interactions for this drug.
There are no moderate interactions for this drug.
Contraindications
*History of seizures.
*Moderate or severe renal impairment (Clcr 50 mL/minute or less).
*History of hypersensitivity to dalfampridine or 4-aminopyridine; reactions have included anaphylaxis.
There are no contraindication contraindications for this drug.
There are no severe contraindications for this drug.
There are no moderate contraindications for this drug.
Adverse reactions
The most common adverse effects occurring in 2% or more of patients and at a rate greater than placebo with dalfampridine include urinary tract infections, insomnia, dizziness, headache, nausea, asthenia, back pain, balance disorder, multiple sclerosis relapse, paresthesia, nasopharyngitis, constipation, dyspepsia, and pharyngolaryngeal pain.
There are no severe adverse reactions for this drug.
There are no less severe adverse reactions for this drug.
Precautions
No enhanced messaging available.
The safety and efficacy of dalfampridine have not been established in patients younger than 18 years of age.
There are no adequate data on the developmental risk associated with dalfampridine use in pregnant women. In animal studies, decreased offspring viability and growth were reported at clinically relevant doses.
Administration of oral dalfampridine to pregnant rats and rabbits throughout organogenesis resulted in no evidence of developmental toxicity in either species. The highest doses tested (10 mg/kg/day in rats, 5 mg/kg/day in rabbits), which were associated with maternal toxicity, are approximately 5 times the maximum recommended human dose ona body surface area basis.
There are no data on the presence of dalfampridine in human milk; its effects on the breastfed infant and milk production are also unknown. The benefits of dalfampridine therapy to the woman as well as the benefits of breast-feeding should be weighed against the potential risk to the infant from exposure to the drug or from the underlying maternal condition.
Modification of dalfampridine dosage is not necessary based solely on age. However, the drug is eliminated by the kidneys and the fact that mild renal impairment is common in adults 50 years of age or older should be considered.
There is insufficient experience with use of dalfampridine in geriatric patients 65 years of age or older to determine whether such individuals respond differently than younger individuals.
Dalfampridine is substantially eliminated by kidneys. Although modification of dalfampridine dosage is not necessary based solely on age, mild renal impairment is common in adults 50 years of age or older. Pharmacokinetic analysis showed that dalfampridine clearance modestly decreased with increasing age, but not sufficiently to necessitate age-based dose modification. Other reported clinical experience has identified no differences in responses between the elderly and younger patients. Because the risk of adverse reactions (including seizures) may be greater in patients with impaired renal function, it is particularly important to determine estimated Clcr in geriatric patients prior to initiation of dalfampridine.
ICD codes
No ICD codes are available for this drug.
Formulary status
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Last reviewed · Source: First Databank (FDB) drug data
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