Skip to Content


Medically reviewed by Last updated on May 2, 2020.


(dal FAM pri deen)

Index Terms

  • 4-aminopyridine
  • 4-AP
  • EL-970
  • Fampridine
  • Fampridine-SR

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Tablet Extended Release 12 Hour, Oral:

Ampyra: 10 mg

Generic: 10 mg

Brand Names: U.S.

  • Ampyra

Pharmacologic Category

  • Potassium Channel Blocker


Nonspecific potassium channel blocker which improves conduction in focally demyelinated axons by delaying repolarization and prolonging the duration of action potentials. Enhanced neuronal conduction is thought to strengthen skeletal muscle fiber twitch activity, thereby, improving peripheral motor neurologic function.


Rapid and complete


Vd: 2.6 L/kg


Limited metabolism; in vitro data suggests hepatic metabolism to 3-hydroxy-4-aminopyridine occurs primarily via CYP2E1; further conjugated to 3-hydroxy-4-aminopyridine sulfate; metabolites are inactive


Urine (96%; 90% of total dose as unchanged drug); feces (0.5%)

Time to Peak

Plasma: 3-4 hours

Half-Life Elimination

5.2-6.5 hours; prolonged in severe renal impairment (~3 times longer)

Protein Binding

Negligible; predominantly unbound to plasma proteins

Special Populations: Renal Function Impairment

Total body clearance of dalfampridine is reduced by ~45% in patients with mild renal impairment (CrCl 51-80 mL/minute), by ~50% in patients with moderate renal impairment (CrCl 30-50 mL/minute), and by ~75% in patients with severe renal impairment (CrCl <30 mL/minute).

Special Populations: Elderly

Clearance modestly decreased with increasing age, but not significantly enough to necessitate a dose modification.

Special Populations: Gender

A pharmacokinetic analysis suggested that women would be expected to have slightly higher Cmax than men.

Use: Labeled Indications

Treatment to improve walking in patients with multiple sclerosis (MS)


Hypersensitivity to dalfampridine, 4-aminopyridine, or any component of the formulation; history of seizure; moderate or severe renal impairment (CrCl ≤50 mL/minute)

Canadian labeling: Additional contraindications (not in US labeling): Mild, moderate, severe renal impairment (CrCl ≤80 mL/minute); concomitant use with compounded 4-aminopyridine or other forms of fampridine; concomitant use with drugs that inhibit organic cation transporter 2 (OCT2), such as cimetidine or quinidine

Dosing: Adult

Multiple sclerosis: Oral: 10 mg every 12 hours (maximum daily dose: 20 mg); no additional benefit seen with doses >20 mg daily

Missed doses: Do not administer double or extra doses if a dose is missed.

Dosing: Geriatric

Refer to adult dosing.



May be administered with or without food. Do not chew, crush, dissolve, or divide tablet.

Bariatric surgery: Tablet, extended release: Some institutions may have specific protocols that conflict with these recommendations; refer to institutional protocols as appropriate. Film-coated tablet; do not cut, crush or chew. No IR formulation available.

Dietary Considerations

May be taken with or without food.


Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F).

Drug Interactions

Cimetidine: May increase the serum concentration of Dalfampridine. Management: Recommendations differ significantly between international labelings in regards to the concomitant use of dalfampridine (referred to as fampridine in Canada) and cimetidine. Consult appropriate product labeling. Monitor therapy

Dolutegravir: May increase the serum concentration of Dalfampridine. Management: Consider alternatives to this combination. Carefully weigh the risk of seizures against the benefit of combining dolutegravir with dalfampridine. Non-US labels list this combination as contraindicated. Consider therapy modification

MetFORMIN: May increase the serum concentration of Dalfampridine. Dalfampridine may increase the serum concentration of MetFORMIN. Monitor therapy

QuiNIDine: May increase the serum concentration of Dalfampridine. Management: Recommendations differ significantly between international labelings in regards to the concomitant use of dalfampridine (referred to as fampridine in Canada) and quinidine. Consult appropriate product labeling. Monitor therapy

Adverse Reactions

The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.

>10%: Genitourinary: Urinary tract infection (12%)

1% to 10%:

Central nervous system: Insomnia (9%), dizziness (7%), headache (7%), equilibrium disturbance (5%), paresthesia (4%)

Gastrointestinal: Nausea (7%), constipation (3%), dyspepsia (2%)

Neuromuscular & skeletal: Weakness (7%), back pain (5%), acute exacerbations of multiple sclerosis (4%)

Respiratory: Nasopharyngitis (4%), pharyngolaryngeal pain (2%)

<1%, postmarketing and/or case reports: Hypersensitivity reaction, seizure, vomiting


Concerns related to adverse reactions:

• Anaphylaxis: May cause anaphylaxis or severe allergic reactions; symptoms have included respiratory compromise, urticaria, and angioedema (throat and tongue). Discontinue immediately and administer appropriate medical care if a severe allergic reaction occurs.

• Seizures: Associated with a dose-dependent risk of seizure; seizures may occur within days to weeks after treatment initiation and have been reported more frequently in patients with no history of seizures. Discontinue use and do not reinitiate therapy if seizure occurs during treatment. Use is contraindicated in patients with a history of seizures. Assess risk of seizure prior to treatment initiation; use caution or avoid in patients who may have a lower seizure threshold due to predisposing factors.

• Urinary tract infection: Urinary tract infections were reported more frequently in patients receiving dalfampridine (compared to placebo),

Disease-related concerns:

• Renal impairment: Use in renal impairment is associated with an increased risk of seizure and other adverse events, primarily neurologic effects, due to increased serum concentrations; elimination is predominately via the kidneys as unchanged drug. US labeling contraindicates use in moderate-to-severe renal impairment (CrCl ≤50 mL/minute). Canadian labeling contraindicates use in mild, moderate, and severe renal impairment (CrCl ≤80 mL/minute).

Concurrent drug therapy issues:

• 4-aminopyridine formulations: Sustained release products available in the United States (dalfampridine) or in Canada (fampridine) should not be administered with other 4-aminopyridine formulations (eg, compounded immediate release fampridine).

Other warnings/precautions:

• Name confusion: The chemical entity of 4-aminopyridine is referred to with a generic name of dalfampridine in the US and with a generic name of fampridine in Canada.

Monitoring Parameters

Renal function (baseline and at least annually thereafter); EEG; walking ability

Pregnancy Considerations

Information related to the use of dalfampridine in pregnancy is limited (Maillart 2016).

Patient Education

What is this drug used for?

• It is used to treat MS (multiple sclerosis).

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Nausea

• Headache

• Loss of strength and energy

• Fatigue

• Trouble sleeping

• Back pain

• Nose irritation

• Throat irritation

• Constipation

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Urinary tract infection like blood in the urine, burning or painful urination, passing a lot of urine, fever, lower abdominal pain, or pelvic pain.

• Severe dizziness

• Passing out

• Seizures

• Change in balance

• Shortness of breath

• Burning or numbness feeling

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a limited summary of general information about the medicine's uses from the patient education leaflet and is not intended to be comprehensive. This limited summary does NOT include all information available about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not intended to provide medical advice, diagnosis or treatment and does not replace information you receive from the healthcare provider. For a more detailed summary of information about the risks and benefits of using this medicine, please speak with your healthcare provider and review the entire patient education leaflet.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.