Amifampridine
Lambert-Eaton Myasthenic Syndrome
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Drug Status
Government Approvals
US(FDA)
WHO Essential Medicine
NO
Known Teratogen
NO
Pharmaceutical Class
Potassium Channel Blocker
Controlled Drug Substance
NO
Amifampridine
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Click HereSummary
Amifampridine is used to treat Lambert-Eaton myasthenic syndrome (LEMS), a rare autoimmune disorder that affects the connection between nerves and muscles, leading to muscle weakness.
Amifampridine works by blocking potassium channels. This enhances the release of a chemical called acetylcholine, which improves muscle strength and helps alleviate the muscle weakness associated with LEMS.
For adults and children weighing 45 kg or more, the usual daily dose is 15 mg to 30 mg, divided into 3 to 5 doses. For children weighing less than 45 kg, the dose is 5 mg to 15 mg daily, divided into 3 to 5 doses.
Common side effects of Amifampridine include a tingling sensation, upper respiratory tract infection, abdominal pain, nausea, diarrhea, headache, and elevated liver enzymes. Serious adverse effects include seizures and hypersensitivity reactions.
Amifampridine is contraindicated in patients with a history of seizures and those allergic to amifampridine phosphate or other aminopyridines. It can cause seizures even in patients without a history of them. If a seizure occurs, discontinue use and consult a healthcare provider. Hypersensitivity reactions, including anaphylaxis, may also occur.
Indications and Purpose
What is Amifampridine used for?
Amifampridine is indicated for the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults and pediatric patients aged 6 years and older. LEMS is a rare autoimmune disorder that affects the connection between nerves and muscles, leading to muscle weakness.
How does Amifampridine work?
Amifampridine acts as a potassium channel blocker, which enhances the release of acetylcholine at the neuromuscular junction. This increase in acetylcholine helps improve muscle strength in patients with Lambert-Eaton myasthenic syndrome (LEMS).
Is Amifampridine effective?
The efficacy of Amifampridine for treating Lambert-Eaton myasthenic syndrome (LEMS) was demonstrated in two randomized, double-blind, placebo-controlled studies. Patients who continued Amifampridine treatment showed less worsening in muscle weakness and global impression scores compared to those who switched to placebo, indicating its effectiveness in managing LEMS symptoms.
How does one know if Amifampridine is working?
The benefit of Amifampridine is evaluated through clinical assessments such as the Quantitative Myasthenia Gravis (QMG) score and the Subject Global Impression (SGI) score. These measures assess muscle weakness and the patient's perception of treatment effects, respectively, to determine the medication's effectiveness.
Directions for Use
What is the usual dose of Amifampridine?
For adults and children weighing 45 kg or more, the usual daily dose of Amifampridine is 15 mg to 30 mg, divided into 3 to 5 doses. The maximum single dose is 20 mg, and the maximum total daily dose is 100 mg. For children weighing less than 45 kg, the dose is 5 mg to 15 mg daily, divided into 3 to 5 doses, with a maximum single dose of 10 mg and a maximum total daily dose of 50 mg.
How do I take Amifampridine?
Amifampridine can be taken with or without food. There are no specific food restrictions mentioned, but always follow your healthcare provider's instructions. If you miss a dose, skip it and take the next dose at the scheduled time. Do not double the dose to make up for a missed one.
For how long do I take Amifampridine?
Amifampridine is typically used for long-term management of Lambert-Eaton myasthenic syndrome (LEMS). The duration of use depends on the patient's response and tolerability, as well as the doctor's recommendation.
How long does it take for Amifampridine to start working?
Amifampridine reaches peak plasma concentration within 20 minutes to 1 hour after administration, suggesting it begins to work relatively quickly. However, the exact time for noticeable effects can vary between individuals.
How should I store Amifampridine?
Store Amifampridine tablets at room temperature between 68°F to 77°F (20°C to 25°C). If preparing a suspension, store it in the refrigerator between 36°F to 46°F (2°C to 8°C) and use it within 24 hours. Discard any unused suspension after this period.
Warnings and Precautions
Who should avoid taking Amifampridine?
Amifampridine is contraindicated in patients with a history of seizures and those allergic to amifampridine phosphate or other aminopyridines. It can cause seizures, even in patients without a history of them. If a seizure occurs, discontinue use and consult a healthcare provider. Hypersensitivity reactions, including anaphylaxis, may also occur.
Can I take Amifampridine with other prescription drugs?
Amifampridine may interact with drugs that lower the seizure threshold, increasing the risk of seizures. It can also interact with drugs that have cholinergic effects, potentially increasing the risk of adverse reactions. Always inform your healthcare provider about all medications you are taking to avoid harmful interactions.
Can I take Amifampridine with vitamins or supplements?
From all available and reliable information, there is no confirmed data on this. Please consult a doctor for personalized advice.
Can Amifampridine be taken safely while pregnant?
There are no human studies on the developmental risk of Amifampridine during pregnancy. Animal studies have shown developmental toxicity at doses lower than therapeutic levels. Pregnant women should consult their healthcare provider to weigh the benefits and risks. A pregnancy registry is available to monitor outcomes.
Can Amifampridine be taken safely while breastfeeding?
There is no data on the presence of Amifampridine in human milk or its effects on the breastfed infant. In lactating rats, the drug was excreted in milk. Consider the benefits of breastfeeding along with the mother's need for Amifampridine and any potential risks to the infant.
Is Amifampridine safe for the elderly?
For elderly patients, Amifampridine should be used cautiously, starting at the low end of the dosing range. This is due to the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy in older adults. Close monitoring for adverse reactions is recommended.
Is it safe to exercise while taking Amifampridine?
From all available and reliable information, there is no confirmed data on this. Please consult a doctor for personalized advice.
Is it safe to drink alcohol while taking Amifampridine?
From all available and reliable information, there is no confirmed data on this. Please consult a doctor for personalized advice.