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Last reviewed on RxList: 5/15/2019
Ruzurgi Side Effects Center

Medical Editor: John P. Cunha, DO, FACOEP

Last reviewed on RxList 5/15/2019

Ruzurgi (amifampridine) is a potassium channel blocker indicated for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in patients 6 to less than 17 years of age. Common side effects of Ruzurgi include:

The initial dose of Ruzurgi for patients 6 to less than 17 years of age weighing 45 kg or more is 15 mg to 30 mg daily, in divided doses, increased daily in 5 mg to 10 mg increments, divided in up to 5 doses daily. The initial dose of Ruzurgi for patients 6 to less than 17 years of age weighing less than 45 kg is 7.5 mg to 15 mg daily, in divided doses, increased daily in 2.5 mg to 5 mg increments, divided in up to 5 doses daily. Ruzurgi may interact with drugs that lower seizure threshold and drugs with cholinergic effects. Tell your doctor all medications and supplements you use. Tell your doctor if you are pregnant or plan to become pregnant before using Ruzurgi; it is unknown how it would affect a fetus. It is unknown if Ruzurgi passes into breast milk. Consult your doctor before breastfeeding.

Our Ruzurgi (amifampridine) Tablets, for Oral Use Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Ruzurgi Professional Information


The following serious adverse reactions are described elsewhere in the labeling:

Clinical Trials Experience

Because clinical studies are conducted under widely varying conditions, adverse reaction rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical studies of another drug and may not reflect the rates observed in practice.

In a double-blind, 3-way crossover, pharmacology study to assess the effects of RUZURGI on QTc interval prolongation, RUZURGI was administered at doses greater than the maximum recommended dose (120 mg administered as 4 equal doses of 30 mg at 4-hour intervals) to 52 healthy adult volunteers [see CLINICAL PHARMACOLOGY]. Adverse reactions that occurred in at least 5% of subjects during RUZURGI treatment and with incidence at least 2% greater than during placebo treatment are displayed in Table 2.

Table 2: Adverse Reactions Occurring in at Least 5% of Subjects During RUZURGI Treatment and With at Least 2% Greater Incidence Than Placebo

Adverse Reaction RUZURGI
(N=52) %
(N=49) %
P aresthesia/Dysesthesia* 69 2
Abdominal pain** 25 0
Dyspepsia 17 2
Dizziness 12 0
Nausea 10 2
Back pain 8 2
Hypoesthesia 6 0
Muscle spasms 6 2
* Includes paresthesia, dysesthesia, and oral dysethesia.
** Includes abdominal pain and upper abdominal pain.

Subjects classified as poor metabolizers based on rate of metabolism were more likely to experience adverse reactions during RUZURGI treatment than intermediate or normal metabolizers [see CLINICAL PHARMACOLOGY].

Expanded Access Experience

In expanded access programs, 162 patients with LEMS (54% female) were treated with RUZURGI. Among patients with available exposure data, the median duration of treatment was 1.7 years (range 1 day to 27.6 years) for a total of 766.4 person years. Patient age at the time RUZURGI was initiated ranged from 21 to 84 years (mean 58.7 years). The median of the maximum total daily dosage was 75 mg/day.

In general, the most frequent adverse reactions observed in the expanded access programs were similar to those observed in the QT study. Additionally, the following adverse reactions were reported in ≥5% of patients: falls, diarrhea, pneumonia, dyspnea, arthralgia, asthenia, depression, dysphagia, headache, insomnia, vision blurred, anemia, anxiety, constipation, feeling cold, gastroesophageal reflux disease, and pain. Because these reactions were captured retrospectively from expanded access programs, it is not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Pediatric Patients (6 To Less than 17 Years Of Age)

Safety of RUZURGI was evaluated in pediatric LEMS and non-LEMS patients 6 to less than 17 years of age who were treated in expanded access programs. There were 15 patients ages 6 to less than 17 years who received RUZURGI, of whom 9 received RUZURGI for at least 1 year. Adverse reactions reported in pediatric patients 6 to less than 17 years of age were similar to those seen in adult patients.

Read the entire FDA prescribing information for Ruzurgi (Amifampridine Tablets)

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© Ruzurgi Patient Information is supplied by Cerner Multum, Inc. and Ruzurgi Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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