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Amifampridine Dosage

Medically reviewed by Last updated on Feb 1, 2019.

Applies to the following strengths: 10 mg

Usual Adult Dose for Lambert-Eaton Myasthenic Syndrome

Initial dose: 15 mg to 30 mg orally daily in divided doses (3 to 4 times daily); dose may be increased by 5 mg daily every 3 or 4 days
-Maximum single dose: 20 mg
-Maximum daily dose: 80 mg/day
-If a dose is missed, patients should not take double or extra doses.

Use: For the treatment of Lambert-Eaton myasthenic syndrome (LEMS) in adults

Renal Dose Adjustments

Mild (CrCl 60 to less than 90 mL/min), moderate (CrCl 30 to less than 60 mL/min), or severe (CrCl 15 to less than 30 mL/min) renal impairment: The recommended starting dose is 15 mg orally daily in 3 divided doses.
End-stage (CrCl less than 15 mL/min) renal disease: Data not available

Liver Dose Adjustments

The recommended starting dosage of FIRDAPSE in patients with any degree of hepatic impairment is 15 mg orally daily in 3 divided doses.

Dose Adjustments

Known N-acetyltransferase 2 (NAT2) Poor Metabolizers:
-Initial dose is 15 mg orally daily in 3 divided doses.


-Hypersensitivity to the active component or any of the ingredients
-History of seizures

Safety and efficacy have not been established in patients younger than 18 years.

Consult WARNINGS section for additional precautions.


Data not available

Other Comments

Administration advice:
-This drug can be taken with or without food.
-The tablets may be divided in half at the score, if needed.
-Do not take a double dose to make up for a missed dose.

Storage requirements:
-Store tablets at 20C to 25C with excursions permitted from 15C to 30C (59F to 86F).

Patient advice:
-Read the patient information leaflet before taking this drug.
-Seek medical help immediately if you experience hypersensitivity or seizures.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Frequently Asked Questions