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Amifampridine Side Effects

The most commonly reported side effects of amifampridine include asthenia, paraesthesia, and fall, based on 3,173 FDA adverse event reports from 2005 to 2025. 10.4% of reports found the drug to be ineffective.

Amifampridine side effects

Percentages show how often each reaction appears relative to total reports for amifampridine.

1
Asthenia10.5%333
2
Drug Ineffective10.4%331
3
Paraesthesia8.8%278
4
Fall7.8%249
5
Fatigue6.5%206
6
Paraesthesia Oral6.3%201
7
Nausea6.2%198
8
Muscular Weakness5.8%183
9
Headache5.7%181
10
Condition Aggravated5.3%168
11
Diarrhoea5.1%161
12
Dizziness5.0%159
13
Dyspnoea4.9%157
14
Gait Disturbance4.9%157
15
Off Label Use4.5%144

These are voluntary reports and do not establish that amifampridine caused these reactions.

Report severity

59.3%Serious1,881 reports
30.4%Hospitalizations966 reports
7.4%Fatal235 reports

Seriousness is determined by the reporter, not by OpenClaim.

Amifampridine drug interactions

Other drugs that appear in adverse event reports alongside amifampridine. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Fingolimod9.2%293
2
Pyridostigmine-bromide3.3%105
3
Prednisone2.6%81
4
Interferon1.5%49
5
Teriflunomide1.2%38
6
Azathioprine1.0%32
7
Natalizumab0.9%27
8
Mycophenolate0.8%26
9
Alemtuzumab0.7%23
10
Prednisolone0.7%23
11
Ocrelizumab0.7%23
12
Methotrexate0.7%21
13
Acetaminophen0.6%19
14
Pregabalin0.6%18
15
Baclofen0.5%16

Taken alongside

1
Pyridostigmine-bromide27.4%868
2
Ergocalciferol21.7%687
3
Acetaminophen14.6%464
4
Levothyroxine-sodium13.7%435
5
Aspirin13.6%432
6
Prednisone13.0%413
7
Gabapentin10.7%339
8
Albuterol9.7%307
9
Cyanocobalamin9.5%301
10
Omeprazole9.3%294
11
Atorvastatin-calcium8.1%257
12
Metoprolol7.8%248
13
Pantoprazole-sodium7.7%245
14
Ibuprofen6.6%211
15
Baclofen6.6%210

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports amifampridine side effects

60.4% of amifampridine adverse event reports involve female patients and 37.1% involve male patients. The largest age group is adult at 55%. These figures reflect who reports side effects, not underlying risk.

Sex

Female60.4%
Male37.1%
Unknown2.5%

Age group

< 20.7%
2–111.1%
12–171.3%
18–6455.0%
65+41.7%

What is amifampridine used for

Conditions and purposes for which patients were taking amifampridine when the adverse event was reported.

AbasiaAmyotrophic Lateral SclerosisAnti-vgcc Antibody PositiveAstheniaAtaxiaAutoimmune DisorderAmyotrophic Lateral SclerosisAstheniaBalance DisorderBreast Cancer FemaleChronic Inflammatory Demyelinating PolyradiculoneuropathyCognitive DisorderCongenital Myasthenic SyndromeCongenital Myasthenic SyndromeCytogenetic Abnormality

Showing 15 of 76 indications

Amifampridine brand names and reporting trend

Amifampridine is sold under brand names including Firdapse, Ruzurgi.

Brand names

Firdapse640
Ruzurgi98

Quarterly reports (20052025)

2005201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking amifampridine with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.