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.

Read the Medication Guide provided by your pharmacist before you start using dalfampridine and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor, usually twice a day. Swallow this medication whole. Do not crush, chew, or break this medication. Doing so can release all of the drug at once, increasing the risk of side effects. If you cannot swallow the tablets whole, talk with your doctor.

Dosage is based on your medical condition and response to treatment. To reduce the risks of side effects (such as seizures), do not take more medication or take it more often than prescribed. Your condition will not improve any faster and your risks of side effects will increase. Do not take more than 2 doses in a day. Take each dose 12 hours apart.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day.

Tell your doctor if your condition lasts or gets worse.

Trouble sleeping (insomnia), dizziness, nausea, and headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• frequent/burning/painful urination
• back pain
• pink/bloody urine
• new/worsening balance problems

Get medical help right away if you have any very serious side effects, including:

• mental/mood changes (such as severe confusion, memory problems)
• seizure

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before taking dalfampridine, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• kidney disease
• seizures

This drug may make you dizzy. Alcohol or marijuana (cannabis) can make you more dizzy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this medication passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Check all prescription and compounded medicine labels carefully since this medication might be similar to other drugs you take. Dalfampridine is also known as 4-AP, 4-aminopyridine, and fampridine. Taking these drugs together could harm you (increased seizure risk). Ask your doctor or pharmacist if you are not sure about any medicines you take.

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose may include: seizures, confusion, shaking (tremor).

Do not share this medication with others.

Lab and/or medical tests (such as kidney function) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.