What is Dalfyra?

Dalfyra (dalfampridine) is a potassium channel blocker. Dalfyra is a prescription medicine used to improve walking in adults with multiple sclerosis (MS). It is not known if Dalfyra is safe or effective in children less than 18 years old.


Dalfyra can cause a seizure (convulsions), even if you have never had one before. Taking too much dalfampridine may increase your risk of seizure. Kidney problems may also increase your risk. Your kidney function may need to be tested before you start taking this medicine.

Stop taking Dalfyra and call your doctor at once if you a seizure, pain or burning when you urinate, problems with your balance, numbness or tingly feeling, or a relapse of your MS symptoms.

You should not use Dalfyra if you are allergic to dalfampridine or 4-aminopyridine, or if you have:

  • moderate to severe kidney disease
  • if you’ve ever had a seizure

Dalfyra can cause a seizure, even if you never had one before. Your risk may also be higher if you have kidney problems or are older than 50.

To make sure Dalfyra is safe for you, tell your doctor if you have ever had:

  • kidney disease
  • if you also take a form of this medicine obtained from a compounding pharmacy (fampridine, or 4-aminopyridine)

Older adults may be more sensitive to the effects of this medication.

It is not known if dalfampridine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Ask a doctor if it is safe to breastfeed while using this medicine.

Dalfyra is not approved for use by anyone younger than 18 years old.

How should I take Dalfyra?

Take Dalfyra exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Taking too much dalfampridine may increase your risk of seizure. Space your doses 12 hours apart. Do not take more than 2 tablets in 24 hours.

You may take Dalfyra with or without food.

Swallow the tablet whole and do not crush, chew, or break it. Breaking the pill may cause too much of the drug to be released at one time which can increase your risk of a seizure.

Do not use a tablet that has been crushed or broken.

Storage condition: Store at room temperature away from moisture and heat. Do not use past the expiration date on the label.

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help center.

Overdose can cause confusion or seizures.

What should I avoid while taking Ampyra?

Follow your doctor’s instructions about any restrictions on food, beverages, or activity.

Side effects

Get emergency medical help if you have signs of an allergic reaction to Ampyra: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Stop taking Dalfyra and call your doctor right away if you have a seizure.

Call your doctor at once if you have:

  • pain or burning when you urinate
  • relapse or worsening of MS symptoms

Common Dalfyra side effects may include:

  • weakness, MS relapse
  • painful urination
  • dizziness, balance problems
  • numbness or tingling
  • sleep problems (insomnia)
  • nausea, constipation, upset stomach
  • stuffy nose, sinus pain, sore throat
  • headache, back pain

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

What other drugs will affect Dalfyra?

Tell your doctor about all your other medicines, especially:

  • cimetidine

This list is not complete. Other drugs may interact with dalfampridine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.