Health Library

Amifampridine (By mouth)

Amifampridine (am-i-FAM-pri-deen)

Treats Lambert-Eaton myasthenic syndrome (LEMS).

Brand Name(s):

Firdapse

When This Medicine Should Not Be Used:

How to Use This Medicine:

Tablet

• Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
• The tablets may be divided in half at the score (line at the center) if you need less than a full tablet to get the right dose.
• If your child cannot swallow the tablet, you may prepare a suspension:
  • Ruzurgi®: Mix 3 tablets with 30 milliliters (mL) of water in a 30-mL container, then shake the mixture well for 30 seconds. You may give the dose using an oral dosing syringe or feeding tube. Shake well before giving each dose.
  • Firdapse®:
    • Do not use any foods or liquids other than sterile water. Add 10 milliliters (mL) of sterile water for each tablet in a 50 to 100 mL container. Secure the cap back on the bottle and wait for 5 minutes. Shake well for 30 seconds.
    • Remove the cap and use the oral dosing syringe to measure the prescribed dose. Insert the tip of the syringe into the mouth and push the plunger to administer the medicine. You may need to repeat these steps depending on the dose and size of the syringe.
    • You may also give this medicine through a feeding tube. Remove the cap and use the oral dosing syringe to measure the prescribed dose. Inject the medicine into the feeding tube right away. You may need to repeat these steps depending on the dose and size of the syringe. Refill the syringe with 10 mL of sterile water. Shake the syringe and inject the sterile water into the feeding tube to flush any remaining medicine from the tube.
• This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
• Read and follow the patient instructions that come with this medicine. Talk to your doctor or pharmacist if you have any questions.
• Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
• Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
• Store Ruzurgi® tablets at room temperature for up to 3 months.
• You may store the mixture in the refrigerator for up to 24 hours. Throw away any unused liquid after 24 hours.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

• Some medicines can affect how amifampridine works. Tell your doctor if you are using pyridostigmine or other aminopyridine medicines (including compounded 3,4-diaminopyridine, amifampridine, or 4-aminopyridine).

Warnings While Using This Medicine:

• Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease or liver disease.
• This medicine may increase your risk of seizures.
• Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.
• Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

• Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
• Blurred vision, dizziness, headache, slow or fast heartbeat
• Numbness, tingling, or burning pain in your hands, arms, legs, or feet
• Seizures, muscle spasms, arm or leg pain

If you notice these less serious side effects, talk with your doctor:

• Back pain
• Cough, sore throat, runny or stuffy nose, body aches
• Nausea, diarrhea, stomach pain, constipation

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088

Last Updated: 9/6/2024