FIRDAPSE is a prescription medicine used to treat adults 17 years of age or older with Lambert-Eaton myasthenic syndrome (LEMS). The safety and efficacy of FIRDAPSE in patients under the age of 17 has not been established.

IMPORTANT SAFETY INFORMATION

What is the most important information I should know about FIRDAPSE?

• FIRDAPSE can cause seizures.
  • You could have a seizure even if you never had a seizure before.
  • Do not take FIRDAPSE if you have ever had a seizure.

Stop taking FIRDAPSE and call your doctor right away if you have a seizure while taking FIRDAPSE.

Do not take FIRDAPSE if you:

• have ever had a seizure.
• are allergic to amifampridine phosphate, or another aminopyridine.

Before you take FIRDAPSE, tell your doctor about all of your medical conditions, including if you:

• are taking another aminopyridine, such as compounded 3,4-diaminopyridine (3,4-DAP)
• have had a seizure
• have kidney problems
• have liver problems
• are pregnant or plan to become pregnant. It is not known if FIRDAPSE will harm your unborn baby. You and your doctor will decide if you should take FIRDAPSE while you are pregnant.
• are breastfeeding or plan to breastfeed. It is not known if FIRDAPSE passes into your breast milk. Talk to your doctor about the best way to feed your baby while taking FIRDAPSE.

Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

How should I take FIRDAPSE?

• Take FIRDAPSE exactly as your doctor tells you to take it. Do not change your dose of FIRDAPSE.
• Do not take more than 2 tablets of FIRDAPSE at one time or more than 8 tablets of FIRDAPSE in a 24-hour period.
• FIRDAPSE can be taken with or without food.
• If you miss a dose of FIRDAPSE, skip that dose and take your next dose at your next scheduled dose time. Do not double your dose to make up the missed dose.
• Do not take FIRDAPSE together with other medicines known to increase the risk of seizures.
• If you take too much FIRDAPSE, call your doctor or go to the nearest hospital emergency room right away.

What are the possible side effects of FIRDAPSE?

• Seizures. See “What is the most important information I should know about FIRDAPSE?”
• Serious allergic reactions, such as anaphylaxis. FIRDAPSE can cause serious allergic reactions. Stop taking FIRDAPSE and call your doctor right away or get emergency medical help if you have:
  • shortness of breath or trouble breathing
  • swelling of your throat or tongue
  • hives

• tingling around the mouth, tongue, face, fingers, toes, and other body parts
• upper respiratory infection
• stomach pain
• nausea
• diarrhea
• headache
• increased liver enzymes
• back pain
• high blood pressure
• muscle spasms

Tell your doctor if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of FIRDAPSE.

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

How should I store FIRDAPSE?

• Store FIRDAPSE at 68ºF to 77ºF (20ºC to 25ºC).
• Safely throw away FIRDAPSE that is out of date or no longer needed.

Keep FIRDAPSE and all medicines out of the reach of children.

If you would like more information, ask your doctor or pharmacist for additional information about FIRDAPSE. You can ask your pharmacist or doctor for additional information about FIRDAPSE that is written for health professionals.

The active ingredient in FIRDAPSE is amifampridine phosphate. Inactive ingredients are calcium stearate, colloidal silicon dioxide, and microcrystalline cellulose.

Please see full Prescribing Information for additional Important Safety Information.