What is dalfampriidine used for?

Dalfampriidine is used to help improve walking in adults who have multiple sclerosis (MS).

Can dalfampriidine cause seizures?

Yes, dalfampriidine can cause seizures, and the risk increases if you take a dose higher than recommended.

What should I do if I have a seizure while taking dalfampriidine?

You should stop taking dalfampriidine immediately and do not start taking it again.

Can I crush or chew dalfampriidine tablets?

No, you must swallow the tablets whole; do not divide, crush, chew, or dissolve them.

Can I take dalfampriidine if I have kidney problems?

Dalfampriidine should not be used if you have moderate or severe kidney impairment (CrCl ≤ 50 mL/min).

Is dalfampriidine safe to take if I am pregnant?

There is not enough data to know the risks to a developing baby during pregnancy.

What are the most common side effects of dalfampriidine?

Common side effects include urinary tract infections, trouble sleeping, dizziness, headache, and nausea.

What should I do if I miss a dose of dalfampriidine?

Do not take a double dose or an extra dose to make up for a missed one.

4-Aminopyridine | CAS 504-24-5 | NUKYPUAOHBNCPY

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Potassium channel blocker

Dalfampriidine (brand name AMPYRA) is a prescription medicine used to help improve walking in adults with multiple sclerosis (MS). It works by blocking certain potassium channels to help nerve signals travel better in damaged nerves.

How it worksDalfampriidine is a potassium channel blocker. It helps improve the conduction of electrical signals in nerves that have lost their protective coating (demyelination).

Brand names:AMPYRA

Used for

Improving walking in adult patients with multiple sclerosis (MS)

Conditions

Multiple Sclerosis

Class

Potassium channel blockerNervous system

How to take

FormsExtended-release tablet

RoutesOral

The standard dose is 10 mg taken twice a day, about 12 hours apart. You can take it with or without food.

Do not crush, chew, divide, or dissolve the tablets. If you miss a dose, do not take an extra or double dose.

Missed dose: Do not take a double or extra dose if you miss a dose of dalfampriidine.

Key warnings

·Dalfampriidine can cause seizures. The risk of having a seizure increases if you take more than the recommended dose.
·If you experience a seizure while taking this medicine, stop taking it and do not start it again.
·This medicine can cause a severe allergic reaction called anaphylaxis. If this happens, stop taking it immediately and do not restart.
·Do not use other forms of 4-aminopyridine (like fampridine) while taking this medicine because they contain the same active ingredient.

Do not use if

·A history of seizures.
·Moderate or severe kidney problems (CrCl ≤ 50 mL/min).
·A known allergy to dalfampriidine or 4-aminopyridine (which can cause anaphylaxis).

Side effects

Common

Urinary tract infectionInsomniaDizzinessHeadacheNauseaWeakness (asthenia)Back painBalance problemsConstipationStomach upset (dyspepsia)

Serious

·Seizures
·Severe allergic reactions (anaphylaxis)

Seek help if

·Seizure
·Anaphylaxis (severe allergic reaction)

Interactions

·Medicines that inhibit OCT2 (like cimetidine) may increase dalfampriidine levels in your body, which can raise the risk of seizures.
·No interaction was found between dalfampriidine and baclofen.

FoodYou can take dalfampriidine with or without food.

Special populations

PregnancyThere is not enough information to know the risks of using dalfampriidine in pregnant women. Some animal studies showed decreased growth and survival in offspring.

PediatricThe safety and effectiveness of this medicine have not been tested in children under 18 years old.

GeriatricStudies did not include enough people over age 65 to be sure how they respond, but kidney function changes with age may affect how the drug is cleared.

Talk to your doctor

Monitor

·Seizure activity
·Signs of allergic reaction (anaphylaxis)
·Kidney function

Questions to ask

·What is my creatinine clearance (CrCl)?
·Am I at risk for seizures with this medication?
·Are there any interactions with my other medications like cimetidine?
·Should I avoid certain foods while taking this?

Pharmacokinetics

OnsetRapidly and completely absorbed from the gastrointestinal tract.

BioavailabilityRelative bioavailability is 96% compared to an aqueous oral solution.

ExcretionSubstantially excreted by the kidneys.

Practical

OverdoseIn clinical trials, people taking much higher doses experienced altered mental states, confusion, or seizures. Most recovered by the next day.

Ingredients

Inactive

colloidal silicon dioxidehydroxypropyl methylcellulosemagnesium stearatemicrocrystalline cellulosepolyethylene glycoltitanium dioxide

Educational summary derived from FDA labeling, AI-assisted. Not medical advice — consult a healthcare professional. Updated 2026-04-25.