Dalfampridine
Dalfampridine is a potassium channel blocker used to improve walking in adults with multiple sclerosis (MS).
🧬 Where this information comes from Click to expand
The clinical label records used on this page are FDA-filed Structured Product Labeling (SPL) retrieved through openFDA. We identified 12 clinical label sets within the page’s selected clinical scope after exact ingredient or ingredient-combination matching and applicable route/form matching. Forms, routes, brands, labelers, strengths, and NDC product-record counts are built separately from matching FDA National Drug Code Directory records. The linked DailyMed document is a representative official source for verification, not the page’s only clinical source. View the linked label on DailyMed →
Dalfampridine (Ampyra) is a potassium channel blocker that can improve walking speed in adults with multiple sclerosis, likely by helping signals pass along nerves that have lost their protective myelin coating. It eases a symptom rather than slowing MS, so it is an add-on to other MS treatment, and it is available as a generic. Most people tolerate it fairly well, with trouble sleeping, dizziness or a urinary tract infection the likeliest complaints. Seizures are the main risk, so it is off limits after any seizure or with moderate to severe kidney impairment, and kidney function needs checking before you start and at least yearly.
Clinical pearls
- Swallow the extended-release tablet whole and never split, crush or chew it, since faster release pushes up levels and seizure risk.
- Space doses about 12 hours apart, and after a missed dose never double up or take an extra tablet.
- Stop any other 4-aminopyridine (fampridine) product before starting, because it is the same active ingredient.
- Check with your pharmacist before taking cimetidine (Tagamet), an acid reducer that can raise dalfampridine levels and seizure risk.
Patient information guide A plain-language walkthrough of Dalfampridine, written from its FDA label.
What Dalfampridine is used for
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Dalfampridine is used to improve walking in adults with multiple sclerosis (MS).
- Ampyra (oral extended-release tablet): improves walking in adults with MS, shown by faster walking speed.
- Dalfampridine extended-release tablets (oral): improve walking in adults with MS, shown by faster walking speed.
How Dalfampridine works
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Dalfampridine is a broad-spectrum potassium channel blocker. In animal studies, it increased the conduction of nerve signals along nerve fibers that have lost their protective coating (demyelinated axons) by blocking potassium channels.
The exact way it produces its benefit in people has not been fully worked out.
Dalfampridine dosage
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Dalfampridine is taken by mouth as an extended-release tablet, twice daily, about 12 hours apart.
- Take it with or without food.
- Swallow tablets whole. Do not divide, crush, chew or dissolve them.
- If you miss a dose, do not take a double or extra dose.
- Do not take more than your prescribed amount. Higher doses brought no added benefit and more side effects, including seizures.
Your kidney function should be known before you start and checked at least yearly.
Dosing details from the FDA-approved label
From the Dalfampridine prescribing information (“Dosage and Administration”). Doses are set by your prescriber for your product, condition, kidney function and age — never change a dose on your own.
- Patients taking dalfampridine (general dosing)
- One 10 mg tablet twice daily, approximately 12 hours apart
- Take with or without food
- Administer tablets whole, do not divide, crush, chew, or dissolve
- If a dose is missed, do not take double or extra doses
- Maximum: 10 mg twice daily; should not be exceeded
- Estimated CrCl should be known before starting and monitored at least annually during treatment
- Mild renal impairment (CrCl 51 to 80 mL/min)
- The label gives no separate regimen
- Plasma levels may approach those seen at 15 mg twice daily, 1.5 times the maximum recommended dose, and may be associated with an increased risk of seizures
- Maximum: 10 mg twice daily
- Potential benefits should be carefully considered against the risk of seizures
- Moderate or severe renal impairment (CrCl≤50 mL/min)
- Contraindicated
- Contraindicated in patients with CrCl≤50 mL/min
Read the label’s full dosing text
2 DOSAGE AND ADMINISTRATION The maximum recommended dosage is 10 mg twice daily (approximately 12 hours apart). There is no evidence of additional benefit with doses greater than 10 mg twice daily. Adverse reactions, including seizures, were more frequent at higher doses. ( 2.1 ) Take with or without food. Administer tablets whole; do not divide, crush, chew, or dissolve ( 2.2 ) Patients should not take double or extra doses if they miss a dose. ( 2.2 ) Estimated creatinine clearance (CrCl) should be known before initiating treatment with Dalfampridine Extended-Release Tablets. In patients with mild renal impairment (CrCl 51 to 80 mL/min), Dalfampridine Extended-Release Tablets may reach plasma levels associated with a greater risk of seizures, and the potential benefits of Dalfampridine Extended-Release Tablets should be carefully considered against the risk of seizures in these patients ( 2.3 , 5.2 , 8.6 ) 2.1 Dosage Information The maximum recommended dosage of Dalfampridine Extended-Release Tablet is one 10 mg tablet twice daily and should not be exceeded. Take doses approximately 12 hours apart. There is no evidence of additional benefit at doses greater than 10 mg twice daily. Adverse reactions, including seizures, and discontinuations because of adverse reactions were more frequent at higher doses. 2.2 Administration Instructions Dalfampridine Extended-Release Tablets can be taken with or without food. Administer tablets whole; do not divide, crush, chew, or dissolve Dalfampridine Extended-Release Tablets. If a dose is missed, patients should not take double or extra doses. 2.3 Renal Monitoring Prior to and During Treatment Estimated creatinine clearance (CrCl) should be known before initiating treatment with Dalfampridine Extended-Release Tablets, and monitored at least annually during treatment with Dalfampridine Extended-Release Tablets. CrCl can be estimated using the following equation (multiply by 0.85 for women): CrCl = (140 - age ) × weight ( kg ) SerumCr ( mg / dl )× 72 2.4 Dosage in Patients with Renal Impairment In patients with mild renal impairment (CrCl 51 to 80 mL/min), Dalfampridine Extended-Release Tablets plasma levels may approach those seen at a dose of 15 mg twice daily, a dose that is 1.5 times the maximum recommended dose and may be associated with an increased risk of seizures.
Excerpted — the section continues on the label. Read the full Dosage and Administration section on DailyMed →
Dalfampridine side effects
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The most common side effects in clinical trials were:
Common side effects
- Urinary tract infection
- Trouble sleeping (insomnia)
- Dizziness
- Headache
- Nausea
- Weakness or feeling tired (asthenia)
- Back pain
- Balance problems
- MS relapse
- Tingling or numbness (paresthesia)
- Cold-like symptoms (nasopharyngitis)
- Constipation
- Indigestion (dyspepsia)
When to get medical help
- Stop the medicine and call your doctor right away if you have a seizure. Do not restart it.
- Get emergency help for signs of a severe allergic reaction (anaphylaxis), such as trouble breathing, hives, or swelling of the throat or tongue. Stop the medicine.
- Call your doctor if you have confusion or other worrying changes after taking too much.
- Tell your doctor if you have signs of a kidney problem, since the drug is cleared by the kidneys.
Vomiting and vertigo (spinning sensation) have also been reported after approval. Seizures and severe allergic reactions (anaphylaxis) are serious and need immediate action.
Dalfampridine warnings and precautions
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- Seizures: The risk rises with dose. Seizures have happened at the recommended dose and in people without a seizure history, often within days to weeks of starting. Stop permanently if one occurs.
- Kidney impairment: The drug is cleared by the kidneys. In mild impairment, levels may approach those linked to a higher seizure risk.
- Anaphylaxis: Signs include breathing trouble, hives, and swelling of the throat or tongue. Stop the drug and get emergency care.
- Other 4-aminopyridine products: Avoid using them together with dalfampridine.
Dalfampridine interactions
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A few drugs and products need care with dalfampridine.
- Other 4-aminopyridine (4-AP, fampridine) products: same active ingredient, so using both raises the chance of dose-related side effects.
- OCT2 inhibitors such as cimetidine: can increase dalfampridine levels and the risk of seizures.
- Baclofen: no interaction was identified.
Interactions listed in the FDA-approved label
From the Dalfampridine prescribing information (“Drug Interactions”): what the manufacturer studied or reported to the FDA.
- OCT2 inhibitors, such as cimetidine: Concurrent treatment may cause increased exposure to dalfampridine, and elevated levels increase the risk of seizures. The potential benefits of taking OCT2 inhibitors concurrently with dalfampridine extended-release tablets should be considered against the risk of seizures.
- Baclofen: No interaction was identified between dalfampridine and baclofen.
Read the label’s full interactions text
7 DRUG INTERACTIONS OCT2 Inhibitors: Concomitant use may cause an increased exposure and potential risk of seizures ( 7.1 ) 7.1 OCT2 Inhibitors Concurrent treatment with OCT2 inhibitors, such as cimetidine, may cause increased exposure to dalfampridine [see Clinical Pharmacology ( 12.3 )] . Elevated levels of dalfampridine increase the risk of seizures [see Warnings and Precautions ( 5.1 , 5.2 )]. The potential benefits of taking OCT2 inhibitors concurrently with dalfampridine extended-release tablets should be considered against the risk of seizures in these patients. 7.2 Baclofen No interaction was identified between dalfampridine and baclofen [see Clinical Pharmacology ( 12.3 )] .
Not a complete list. The label covers the interactions the manufacturer studied or reported, and our own interaction database does not cover every medicine either. Bring your full medication list, including vitamins and herbal products, to your pharmacist.
Before taking Dalfampridine
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- Do not use if you have a history of seizures.
- Do not use if you have moderate or severe kidney impairment.
- Do not use if you are allergic to dalfampridine or 4-aminopyridine.
- Mild kidney impairment: weigh the benefits against the seizure risk with your doctor.
- Older adults: kidney function is more likely to be reduced, so a kidney check is especially important.
- Pregnancy: human data are lacking, and animal studies showed reduced offspring survival and growth.
- Breastfeeding: there are no data on its effect on milk or the infant.
- Under 18: safety and effectiveness have not been established.
Dalfampridine overdose
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Too much dalfampridine can cause seizures, confusion, altered mental state, tremulousness, sweating and amnesia. Some people have developed status epilepticus (seizures that do not stop) and needed intensive care. Anyone who takes too much needs emergency medical help right away.
What Dalfampridine does in the body
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Dalfampridine does not prolong the QTc interval, a heart rhythm measure. It also has no clinically important effect on QRS duration, another heart electrical measure.
How your body processes Dalfampridine
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The extended-release tablet is absorbed rapidly and completely, but more slowly than a liquid form. Peak levels occur about 3 to 4 hours after a dose. Food causes only small changes in exposure, so it can be taken with or without food.
Most of the drug leaves unchanged in the urine, and elimination is nearly complete within 24 hours. The half-life is about 5.2 to 6.5 hours. Kidney impairment reduces clearance of the drug.
How to store Dalfampridine
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Store at 25°C (77°F).
Written from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
Supplements & herbs that interact with Dalfampridine
23 supplements and herbal products have documented interactions with Dalfampridine in the licensed clinical database we use. Most are manageable — but your pharmacist should know about everything you take, including vitamins and herbals.
- Major · 1
- Moderate · 13
- Minor · 9
Educational information from a licensed clinical database (Natural Medicines) — see our data sources & update cadence. Not medical advice: an interaction being documented does not mean it will happen to you; do not start or stop medications or supplements without professional guidance.
Dalfampridine: pharmacist answers to common questions
Quick, plain-English answers to the questions patients ask most about Dalfampridine — the kind of thing our pharmacy team would talk through with you at the counter.
What is this medicine for?
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How should I take it?
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What side effects are common?
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When should I get help right away?
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Why does my kidney function matter?
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Can I take it with other medicines?
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Is Dalfampridine available over the counter?
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When was Dalfampridine first available?
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Who makes Dalfampridine?
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Answers drafted from the FDA-approved label with AI and reviewed by our pharmacy team. How we use AI →
More about Dalfampridine on HelloPharmacist
Dalfampridine forms and strengths (how it comes)
Dalfampridine is available in 1 form. Different forms and brands can have different approved uses, doses, schedules, and directions. Follow the instructions for your exact product, and do not switch forms without guidance from your prescriber or pharmacist.
Need a version that does not list lactose, a gluten source, a dye or gelatin? Inactive ingredients differ by manufacturer: see Dalfampridine inactive ingredients by manufacturer.
Extended-release tablet
How this form is used
- Ampyra is used to improve walking in adults with multiple sclerosis (MS).
- Dalfampridine extended-release tablets are used to improve walking in adults with multiple sclerosis (MS).
- Ampyra is taken about 12 hours apart, with or without food.
- Ampyra tablets should be swallowed whole, not divided, crushed, chewed or dissolved.
- Dalfampridine extended-release tablets are taken about 12 hours apart, with or without food.
- Dalfampridine extended-release tablets should be swallowed whole, not divided, crushed, chewed or dissolved.
Dalfampridine on the U.S. market: products, makers and brands
How Dalfampridine appears in the FDA’s National Drug Code Directory — including its dosage forms, strengths, brand names, manufacturers, and FDA-listed product records. These are directory records, not sales or prescription volume.
10 companies list 11 Dalfampridine product records with the FDA, mostly as extended-release tablet; the earliest marketing or approval year on record is 1956. Brand names on the directory include Ampyra; the rest are generics.
Also listed with the FDA, not a patient dose form: Powder (10) — bulk drug substance sold to compounders/manufacturers and multi-item kits. These aren’t counted in the dose-form total above.
Share of FDA-listed product records by manufacturer — FDA National Drug Code Directory. Record counts are not sales or prescription volume.
How widely Dalfampridine is used (Medicaid data)
A general measure of how commonly Dalfampridine is prescribed, based on Medicaid — one of the largest public drug programs. The figure below is prescriptions filled in Q1–Q4 2025, summed across every form and brand of the drug.
Think of this as a proxy for how widely Dalfampridine is used, drawn from freely available public data. Medicaid is just one program — these numbers don’t include Medicare, other government coverage, or commercial and cash-pay prescriptions, so real-world use is higher than what’s shown here.
How commonly is Dalfampridine prescribed? Of the 1,601 medications we measure, Dalfampridine ranks #841 by Medicaid prescriptions — more than 47% of them.
Utilization by Dalfampridine product
Pick a product to see its own Medicaid numbers. Each chip is one clinical product — a specific strength & dosage form as defined by RxNorm — with brand-name and generic versions combined.
12 HR dalfampridine 10 MG Extended Release Oral Tablet
Summed across the 5 of 28 listed NDC products with Medicaid activity — every brand and generic of this exact strength & form. RxNorm 897021
Shares are of the Medicaid prescriptions shown here. Product grouping follows RxNorm (the National Library of Medicine’s drug terminology), so “one product” means one strength & dosage form regardless of manufacturer. Dollar figures are gross Medicaid reimbursement before mandatory rebates — rebates (often large, especially for brand-name drugs) are confidential, so actual net cost to Medicaid is lower than shown.
Source: Medicaid State Drug Utilization Data (CMS), aggregated by generic ingredient — summed across every NDC (all brands, strengths, salt forms and dosage forms) of Dalfampridine, and across all states and both fee-for-service and managed-care claims. A general popularity signal; it excludes Medicare, commercial insurance and cash prescriptions, so it is not total U.S. use. Based on the 5 of 28 listed Dalfampridine NDCs with Medicaid activity.
Compare Dalfampridine products
A representative set of FDA-listed product records for Dalfampridine — across manufacturers, strengths, and dosage forms, grouped by form with each product’s manufacturer and how the FDA approved it. The same medicine may be made and packaged by different companies, so a single drug can have many directory entries. (It’s also why a refill can look different — a new shape, color, or box — even though it contains the same medication.)
| Strength | Route | Manufacturer / Labeler | Category ⓘ | Details |
|---|---|---|---|---|
| 💊Extended-release tablet | ||||
| 10 mg | Oral | Accord Healthcare Inc. | ANDA | View NDC → |
| 10 mg | Oral | Actavis Pharma, Inc. | ANDA | View NDC → |
| 10 mg | Oral | Ascend Laboratories, LLC | ANDA | View NDC → |
| 10 mg | Oral | Aurobindo Pharma Limited | ANDA | View NDC → |
| 10 mg | Oral | Bryant Ranch Prepack | ANDA | View NDC → |
| 10 mg | Oral | CivicaScript LLC | ANDA | View NDC → |
| 10 mg | Oral | Golden State Medical Supply, Inc. | ANDA | View NDC → |
| 10 mg | Oral | Merz Pharmaceuticals, LLC × 2 listings | NDA | View NDC → |
| 10 mg | Oral | Micro Labs Limited | ANDA | View NDC → |
| 10 mg | Oral | Sun Pharmaceutical Industries, Inc. | ANDA | View NDC → |
Showing 11 of 11 products — FDA National Drug Code Directory. See every product, package size and price: browse all 11 Dalfampridine NDCs →
Dalfampridine side effects reported to the FDA (FAERS)
After a medicine reaches the market, patients, doctors and drugmakers can send the FDA reports of problems they think may be linked to it. Here’s what’s been reported for Dalfampridine — a signal of what to watch for, not proof the drug caused it.
Source: openFDA, from the FDA Adverse Event Reporting System (FAERS). These are voluntary reports — they don’t prove the drug caused the effect, and counts reflect how often something was reported, not how often it actually happens. Reports also often name the very problem the medicine is taken for — a common reason to file one is that the drug didn’t help — so for a pain reliever you may see “pain” high on the list; that points to why the report was filed, not to the drug causing the symptom. This counts every report that lists Dalfampridine in any role, so the total runs higher than the FDA’s official dashboard, which counts only cases where the drug is the suspect. For the authoritative figures, see the FDA FAERS Public Dashboard. Always talk to your pharmacist or doctor.
Dalfampridine FDA approval history
How Dalfampridine went from FDA review to the pharmacy shelf — the key milestones in its regulatory journey.
Source: Drugs@FDA.
Dalfampridine recall history
A recall is when a specific batch of a medicine is pulled from the market — usually a manufacturing issue, not a problem with the drug itself. Class I is most serious, Class III least.
The FDA’s enforcement reports list no Dalfampridine recalls since July 2021.
✅No Dalfampridine recalls on record since July 2021Source: FDA enforcement (recall) reports, via openFDA; our copy was last updated Sep 24, 2026.
RxNorm Concept Web — From Ingredient to Every Form and Strength
This page starts with one ingredient concept (IN). The branches below show its dose-form concepts (SCDF), then the available clinical drug and strength concepts (SCD). Combination products remain separate concepts with their own pages.
RxCUI 897018 1 dose form · 1 strength
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Dose form (SCDF) Extended Release Oral Tablet RxCUI 897020In current FDA listingsClinical drug / strength (SCD) 12 HR dalfampridine 10 MGRxCUI 897021
Look up RxCUI 897018 in the RxCUI Atlas →
RxNorm is the U.S. National Library of Medicine’s normalized drug vocabulary. Its concept hierarchy can include forms that are not currently marketed; the status on each branch compares that concept with current FDA listings. RxCUIs identify vocabulary concepts, not individual packages or manufacturers.
Dalfampridine supply and shortage status
Whether Dalfampridine is in short supply in the U.S. right now, plus any shortage history the FDA has on record. A shortage usually reflects a manufacturing or demand issue — not a safety problem with the drug.
Source: openFDA, from the FDA Drug Shortages database.
💵 What Dalfampridine costs pharmacies (NADAC benchmark)
The national average invoice price pharmacies pay for the drug itself, from CMS's NADAC survey (data as of Sep 30, 2026). This is a supply-cost benchmark — not a retail price and not what you'd pay at the counter.
| Form | Strength | Pharmacy acquisition benchmark | |
|---|---|---|---|
| Tablet, Extended Release · Oral | 10 mg | $0.399 per tablet | NDC details & price history |
Source: CMS National Average Drug Acquisition Cost (NADAC), a survey of retail pharmacy invoice prices. Benchmarks shown are the range across package sizes of a representative product for each form and strength — other manufacturers' products may differ.
Dalfampridine brand names
Dalfampridine is sold under one brand name in the FDA directory — Ampyra. A brand and its generic contain the same active ingredient; the brand name belongs to one company's product.
Who makes Dalfampridine: manufacturers and labelers
10 companies list Dalfampridine products with the FDA. By number of product records, the largest are Merz Pharmaceuticals, LLC, Accord Healthcare Inc., Actavis Pharma, Inc.. Labelers include manufacturers and repackagers; the product in your bottle depends on which one your pharmacy stocks.
Dalfampridine drug class (RxNorm)
Dalfampridine belongs to the Potassium Channel Blocker class.
Classified by RxNorm RxClass — the U.S. National Library of Medicine's standardized drug-classification service (Established Pharmacologic Class from the FDA, the ATC drug family from the WHO, and mechanism of action). Reference only, not medical advice.
Sources for this Dalfampridine page
Core label, product, RxNorm, safety, and utilization data on this page come from the sources identified below. AI-written, editorial, and licensed sections are labeled separately.
How this page is built
HelloPharmacist combines public FDA and NLM records and does not author the underlying clinical facts. The plain-language sections are written with AI from the FDA-approved label text and reviewed by our pharmacy team before publication. Merz Pharmaceuticals, LLC is the representative DailyMed label linked for verification and dates. This is general education, not medical advice: always talk to your doctor or pharmacist about your own medicines. How we build and review drug pages →