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WHAT IS LEMS?

Learn the facts about Lambert-Eaton myasthenic syndrome (LEMS)

LEMS is a severe neuromuscular disorder that causes debilitating, progressive muscle weakness and fatigue. It occurs when the immune system attacks the connections between nerves and muscles, known as the neuromuscular junction (NMJ).

This attack disrupts the nerve cell’s ability to release acetylcholine (ACh), a chemical that helps it send signals to muscle cells. When less ACh is released, muscles can’t contract properly and don’t work as they should. People with LEMS can struggle to walk or do everyday activities.

Woman sitting in a chair with a shadow

What are the symptoms?

The main symptom of LEMS is muscle weakness, especially in the legs and hips. This weakness may fluctuate from day to day. LEMS can make it very difficult to do everyday activities, such as:

Icon of person standing Standing up
Icon of person walking Walking
Icon of person lifting leg to climb Climbing steps
Icon of car Getting into or out of a car
Icon of bed Getting out of bed
Icon of head talking Talking
Icon of apple with bite taken out of it Chewing
Icon of head highlighting throat Swallowing
Icon of barbell Lifting objects

Some patients may have to use assistive equipment, such as a wheelchair or walker, to get around. If you suspect that you may have LEMS, talk to your doctor about the symptoms you’re experiencing and your possible treatment options.

LEMS: Easy to misdiagnose

LEMS is a rare disease, affecting about 3,000 people in the United States. The symptoms can also resemble other more common diseases, like myasthenia gravis, multiple sclerosis, fibromyalgia, or lupus. Many people with LEMS struggle with symptoms for several years and can be misdiagnosed at first.

An early, accurate diagnosis is important because it may help people get started on treatment sooner. LEMS is typically diagnosed through one or more of the following ways:

  • A physical exam to test for symptoms and reflexes
  • Bloodwork to test for certain antibodies
  • An electrodiagnostic test to measure how well muscles and the nerve cells that control them are working

Who treats LEMS?

If you think you may be experiencing the symptoms of LEMS, first talk to your physician. If your physician suspects that you may have LEMS, he or she may refer you to a neurologist or neuromuscular specialist. These types of doctors specialize in neuromuscular diseases like LEMS.

Association with other diseases

If you are diagnosed with LEMS, you are at an increased risk for certain types of cancer. About 50% of people with LEMS have or will develop cancer, especially small cell lung cancer.

This is why people with LEMS are tested for cancer soon after diagnosis and then tested again at three to six months and every six months thereafter for the next two years.

FIRDAPSE Education Brochure

Educational Brochure

Download an educational brochure about LEMS and how FIRDAPSE® may help.

What is FIRDAPSE®?

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?

FIRDAPSE may cause serious side effects, including:

  • 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
  • The most common side effects of FIRDAPSE include:
    • 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, talk to your doctor or pharmacist. 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. Inactive ingredients are calcium stearate, colloidal silicon dioxide, and microcrystalline cellulose.

Please see full Prescribing Information for additional Important Safety Information.

What is FIRDAPSE®?

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?

FIRDAPSE may cause serious side effects, including:

  • 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
  • The most common side effects of FIRDAPSE include:
    • 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, talk to your doctor or pharmacist. 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. Inactive ingredients are calcium stearate, colloidal silicon dioxide, and microcrystalline cellulose.

Please see full Prescribing Information for additional Important Safety Information.