Home Drug Guide Amifampridine

Drug Guide

Generic Name

Amifampridine

Brand Names Ruzurgi

Classification

Therapeutic: Neuropharmacologic agent

Pharmacological: Potassium channel blocker

FDA Approved Indications

Lambert-Eaton Myasthenic Syndrome (LEMS) in patients aged 6 years and older

Mechanism of Action

Amifampridine blocks voltage-gated potassium channels, prolonging the action potential and enhancing calcium influx at presynaptic nerve terminals, which increases the release of acetylcholine and improves neuromuscular transmission.

Dosage and Administration

Adult: Starting dose is typically 10 mg three times daily, titrated based on response and tolerability.

Pediatric: Approved for pediatric patients aged 6 years and older, starting dose usually 0.25 mg/kg three times daily, titrated as needed.

Geriatric: No specific adjustment required, but cautious titration recommended due to potential renal impairment.

Renal Impairment: Use with caution; dose adjustments may be necessary based on severity.

Hepatic Impairment: No specific data; use caution and monitor for adverse effects.

Pharmacokinetics

Absorption: Rapid absorption with peak plasma concentrations within 0.5 to 2 hours.

Distribution: Widely distributed; volume of distribution approximately 0.4-0.7 L/kg.

Metabolism: Metabolized minimally; primarily excreted unchanged.

Excretion: Excreted mainly by the kidneys, both as unchanged drug and metabolites.

Half Life: Approximately 2-4 hours.

Contraindications

Hypersensitivity to amifampridine or any component of the formulation.

Precautions

Seizure risk increased; avoid in patients with seizure disorders.
Monitor renal function.
Use with caution in patients with a history of cardiovascular disease or electrolyte abnormalities.

Adverse Reactions - Common

Nausea (Common)
Insomnia (Common)
Dizziness (Common)

Adverse Reactions - Serious

Seizures (Uncommon but serious)
Cardiac arrhythmias (Rare)
Hypokalemia and electrolyte disturbances (Rare)

Drug-Drug Interactions

Other drugs that lower seizure threshold (e.g., antidepressants, antipsychotics).

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor neuromuscular function, renal function, electrolyte levels, and for seizure activity.

Diagnoses:

Risk for seizures.
Impaired physical mobility.

Implementation: Administer as prescribed; monitor for adverse effects; counsel patient about signs of adverse effects.

Evaluation: Assess improvement in muscle strength and function, monitor for adverse effects.

Patient/Family Teaching

Take medication exactly as prescribed.
Report symptoms of seizures, cardiac irregularities, or severe side effects immediately.
Avoid activities requiring alertness if dizziness or sedation occurs.
Maintain adequate hydration and electrolyte balance.

Special Considerations

Black Box Warnings:

Seizure risk associated with amifampridine use.

Genetic Factors: None specific.

Lab Test Interference: May alter serum electrolyte levels; monitor as indicated.

Overdose Management

Signs/Symptoms: Seizures, cardiac disturbances, and severe adverse effects may occur.

Treatment: Supportive care, seizure management with anticonvulsants if necessary, activated charcoal if ingestion recent, and symptomatic treatment.

Storage and Handling

Storage: Store at room temperature, away from moisture and heat.

Stability: Stable under recommended storage conditions for the duration of the shelf life.