Drugs › Potassium channel blocker
Brand name · Dalfampridine
Ampyra: adverse event reports filed with FDA
56,261 reports list it as a suspect or interacting product, 2010–2026. Class: Potassium channel blocker. Also reported as Ampyra Tablet 10mg, Ampyra Tablet, Ampyra Er.
- 56,261
- reports as suspect product
- 0.3% of all reports · about 3,463 a year
- 295
- reports, 12 months to June 2026
- 147 in the 12 months before
- 23%
- marked serious by the reporter
- 26.9% across the class
- 2%
- record death among outcomes, as reported
- 1,131 reports · not verified by FDA
Between April 2010 and June 2026, 56,261 adverse event reports received by FDA list the brand name Ampyra (dalfampridine) as a suspect or interacting product. Reports that mention it only as a concomitant medication (9,496) are left out of every figure here.
In the 12 months to June 2026, 295 reports listed it, up 101% from 147 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 3,463 reports a year and 0.3% of the 20,646,523 reports in the database, and 86.8% of the reports for the potassium channel blocker class. How many people take it is not in the data, so a count is not a rate of occurrence.
Reporters most often recorded gait disturbance (16.2%), drug ineffective (12.7%) and fall (9.7%). A report can list several reactions, so shares add to more than 100%; 1,916 different terms appear across these reports. Gait disturbance is recorded in 16.2% of these reports, a larger share than in the median potassium channel blocker drug (11.9%).
23% of the reports are marked serious by the reporter (26.9% across the class); 2% record death among the outcomes and 11.1% record hospitalisation, as reported. 76.5% of the reports came from consumers, and the largest patient age group is 45 to 64 (25.6%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."
Reports by month, five years
Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.
By year received
2026 covers reports received through June 2026 only.
Reactions recorded in the reports
share of Ampyra reports recording the termmedian drug in potassium channel blocker
- Gait disturbancedifficulty walking16.2%9,102
- Drug ineffectivethe medicine did not work as expected12.7%7,121
- Falla fall9.7%5,464
- Therapy cessation7.9%4,419
- Balance disorderproblems with balance6.9%3,901
- Fatiguetiredness6.8%3,801
- Multiple sclerosis relapsea flare of multiple sclerosis6%3,403
- Dizzinesslight-headedness or unsteadiness5.8%3,279
- Condition aggravatedthe condition being treated got worse5.8%3,236
- Urinary tract infectionbladder or urinary infection5.1%2,892
- Insomniadifficulty sleeping5%2,840
- Astheniaweakness or lack of energy4.4%2,492
- Headachehead pain4.3%2,432
- Mobility decreasedreduced ability to move about4.2%2,389
- Nauseafeeling sick3.8%2,145
- Multiple sclerosis3.8%2,140
- Muscular weaknessmuscle weakness3.5%1,985
- Drug dose omissiona dose was missed3.4%1,930
- Memory impairmentmemory problems3.3%1,843
- Inappropriate schedule of drug administrationthe medicine was taken at the wrong times3%1,663
- Flushingsudden reddening or warmth of the skin2.8%1,579
- Back painback pain2.6%1,478
- Depressionlow mood2.6%1,471
- Malaisegeneral feeling of being unwell2.6%1,467
- Painpain, site not specified2.6%1,466
- Hypoaesthesianumbness2.5%1,387
- Therapeutic response unexpected2.4%1,373
- Paraesthesiatingling or pins and needles2.4%1,364
- Pain in extremitypain in an arm or leg2.3%1,307
- Muscle spasmsmuscle cramps2.1%1,200
Top 30 of 1,916 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 3 drugs in the potassium channel blocker class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."
Outcomes recorded
Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 64,845 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."
Patients and reporters
Patient age
Patient sex
Who reported
Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 99.9% of reports give the United States as the country of the event or reporter.
Reason for use recorded
| Indication as recorded (MedDRA) | Reports | Share |
|---|---|---|
| Multiple sclerosis | 22,730 | 40.4% |
| Gait disturbance | 10,993 | 19.5% |
| Balance disorder | 156 | 0.3% |
| Relapsing-remitting multiple sclerosis | 81 | 0.1% |
| Muscular weakness | 63 | 0.1% |
| Asthenia | 48 | 0.1% |
The indication field is filled in by the reporter and is often blank; shares are of all 56,261 reports.
Drugs most often listed in the same reports
| Drug (any role in the report) | Reports | Share of Ampyra reports |
|---|---|---|
| Baclofen | 8,076 | 14.4% |
| Tecfidera | 7,143 | 12.7% |
| Vitamin d | 4,498 | 8% |
| Copaxone | 4,228 | 7.5% |
| Gabapentin | 4,200 | 7.5% |
| Ergocalciferol | 3,750 | 6.7% |
| Tysabri | 2,800 | 5% |
| Avonex | 2,461 | 4.4% |
| Gilenya | 2,354 | 4.2% |
| Aubagio | 2,337 | 4.2% |
Other products listed in reports where Ampyra is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.
In context
| Measure | Ampyra | Potassium channel blocker | All reports |
|---|---|---|---|
| Reports as suspect product | 56,261 | 64,845 | 20,646,523 |
| Share of that pool | — | 86.8% | 0.3% |
| Reports, latest 12 months | 295 | — | 1,332,454 |
| Marked serious | 23% | 26.9% | 57.4% |
| Death recorded among outcomes, per 1,000 reports | 20 | 27 | 91 |
| Hospitalisation recorded, per 1,000 reports | 111 | 133 | 213 |
| Consumer-filed share | 76.5% | 75.1% | 45.8% |
| Top term, share of reports | Gait disturbance 16.2% | median 11.9% | 0.9% |
Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."
Other drugs in the potassium channel blocker class
| Drug | Name type | Reports | Latest 12 months | Marked serious |
|---|---|---|---|---|
| Dalfampridine | generic | 5,760 | 301 | 51.9% |
| Firdapse | brand | 2,824 | 738 | 51.9% |
Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.
Questions about Ampyra reports
How many adverse event reports has FDA received for Ampyra?
56,261 reports list Ampyra as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 295 of them arrived in the latest 12 months. Another 9,496 list it only as a concomitant medication.
What reactions are recorded in Ampyra reports?
gait disturbance (16.2%), drug ineffective (12.7%), fall (9.7%), therapy cessation (7.9%) and balance disorder (6.9%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Ampyra was responsible.
How serious are the reports?
23% are marked serious by the reporter. Among the outcomes recorded, 2% of reports include death and 11.1% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.
Who files these reports?
consumer or non-health professional (76.5%), not given (6.6%) and other health professional (6.1%). Most reports reach FDA through the manufacturer, which must forward reports it receives.
Are reports for Ampyra rising?
295 reports in the 12 months to June 2026, up 101% from 147 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.
Do these reports show that Ampyra was responsible for these reactions?
No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.
Is this a list of the side effects of Ampyra?
No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.
How do I report an adverse event?
Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.
Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Ampyra as a suspect or interacting product; reports listing it only as a concomitant medication (9,496) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.
Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.