Learn About Primary Periodic Paralysis

Primary Periodic Paralysis is a rare neuromuscular disorder

You Are Not Alone: The Power of Education, Advocacy, & Support

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  • Watch our program from the 2020 Periodic Paralysis Association (PPA) virtual conference, where we brought doctors and patients together to speak on topics surrounding PPP. These topics included the diagnosis and impact of PPP, management of PPP, and the support Strongbridge can provide to those living with PPP.

How common is Primary Periodic Paralysis?

Although this condition is very rare, you are not alone. It affects about 4,000 to 5,000 diagnosed individuals in the United States.1

This condition causes attacks that affect your muscles, resulting in extreme weakness or temporary paralysis—most often the inability to move the muscles of the arms and legs.2

Attacks cause symptoms that affect many parts of the body and can vary in how severe they are and how long they last. Most attacks range from 30 minutes to several hours. Some attacks can last for days, but this is infrequent.2,3

Primary Periodic Paralysis affects about 4,000 to 5,000 diagnosed individuals in the united states.

Are there different types of Primary Periodic Paralysis?

Primary Periodic Paralysis is not just 1 condition but a group of long-term neuromuscular disorders.2 The most common forms are hyperkalemic and hypokalemic periodic paralysis; however, other forms exist.4-8

If you have hyperkalemic periodic paralysis9

You have high potassium levels in your blood during attacks

Your attacks can occur without warning and may be triggered by:

  • Potassium-rich food and supplements
  • Changes in activity; rest after exercise
  • Cold temperatures; changes in humidity
  • Stress or fatigue
  • Alcohol
  • Hunger/fasting
  • Extra sleep
  • Pregnancy and menstruation
If you have hypokalemic periodic paralysis10

You have low potassium levels in your blood during attacks

Your attacks can occur without warning and may be triggered by:

  • Exercise and rest after exercise
  • Carbohydrate-rich and heavy meals
  • Sweets
  • Salt
  • Being inactive for a long time
  • Cold temperatures
  • Stress

What causes Primary Periodic Paralysis?

This condition is usually inherited, meaning that it is passed down from a parent to a child. Because of this, it may affect your siblings and other people in your family. That’s why looking into family history is very important. It can potentially shorten the time it takes for a person who is suffering from attacks of weakness to get accurately diagnosed. However, not having the genetic abnormality does not mean you don’t have Primary Periodic Paralysis if you have the signs and symptoms of the condition.2,11

Primary Periodic Paralysis is usually inherited, meaning it can be passed down from a parent to child.

What are the symptoms of Primary Periodic Paralysis?

If you have been diagnosed with Primary Periodic Paralysis, it’s important to understand the symptoms you experience during an attack are generally caused by this condition.

Attacks usually appear in later childhood, before a person reaches the age of 20. However, some people begin having attacks as early as age 2 or even younger.3

Primary Periodic Paralysis attacks cause symptoms that affect many parts of the body and can vary in how severe they are and how long they last. Most attacks range from 30 minutes to several hours. However, some attacks can even last for days, but this is infrequent.2,11

Symptoms of Primary Periodic Paralysis attacks3
Common symptoms of periodic paralysis are found throughout the body.

Symptoms of weakness during an attack commonly affect:

  • Fronts of the thighs
  • Hips
  • Upper arms
  • Calves
  • Shoulders

Attacks may also affect:

  • Lower back
  • Hands
  • Neck & throat
  • Forearms
  • Buttocks
  • Chest
  • Face & jaw
  • Eyelids

How does Primary Periodic Paralysis impact daily living?

Because Primary Periodic Paralysis can be a physically disabling condition, it can take a toll on your ability to participate in everyday activities.2

Primary Periodic Paralysis can affect you between attacks
Lingering symptoms

Not only are attacks potentially debilitating, sometimes symptoms may linger afterward, causing you to feel clumsy, very tired, or weak.2,9

Persistent weakness

As some people age, they may begin to experience persistent muscle weakness, which can make their day-to-day activities more difficult to perform and may affect their quality of life.3

Don’t hesitate to talk with your doctor about a plan for managing either lingering symptoms or persistent weakness

These aspects of the disorder can take an emotional toll on you. This is very common for people with Primary Periodic Paralysis. Don’t be embarrassed to discuss how you are feeling with your doctor. He or she can recommend ways to deal with these emotions.2

How is Primary Periodic Paralysis diagnosed?

Misdiagnosis and delays in diagnosis are common because symptoms can be confused with other more common conditions, such as emotional issues or cardiovascular disorders.2,3,12

The specialists who treat Primary Periodic Paralysis are neurologists and neuromuscular specialists. Talking with doctors who understand the disorder can help avoid delays in diagnosis and treatment.

As previously noted, because Primary Periodic Paralysis is generally an inherited disorder, your doctor will want to know your family history and any relatives who have been affected with this disorder. Your doctor will also want you to have a number of tests, which may include2,3,9:

  • Blood tests (to measure potassium and certain hormone/enzyme levels)
  • Muscle tests
  • Genetic testing (to determine if you have an abnormality in one of the genes associated with Primary Periodic Paralysis)
Learn more about Strongbridge Biopharma’s no-cost genetic testing program.

Educational segment in Primary Periodic Paralysis

Strongbridge Biopharma sponsored an educational segment about Primary Periodic Paralysis on The Balancing Act, “Behind the Mystery: Rare and Genetic Diseases.” The segment features Linda Feld, Vice President of Periodic Paralysis Association (PPA), and Steve Cannon, MD, PhD, neurologist and professor of physiology at UCLA. A broad range of topics related to Primary Periodic Paralysis are addressed within the segment, including symptoms, triggers, misdiagnosis, and genetic testing.


Indication and Important Safety Information

What is KEVEYIS?

KEVEYIS (pronounced keh-VAY-iss) (dichlorphenamide) is a prescription drug used to treat primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and other similar diseases.

What should you tell your healthcare provider before taking KEVEYIS?

Tell your doctor if you are allergic to dichlorphenamide or other sulfa drugs; if you take high doses of aspirin, or if you have lung or liver disease; if you are pregnant, plan to become pregnant, or are breastfeeding or plan to breastfeed.

What should you know about KEVEYIS?

  • Severe allergic and other reactions have happened with sulfonamides (drugs such as KEVEYIS) and have sometimes been fatal. Stop taking KEVEYIS at the first sign of skin rash, swelling, difficulty breathing, or any other unexpected side effect or reaction, and call 911 right away.
  • Tell your healthcare provider if you take aspirin or if another healthcare provider instructs you to begin taking aspirin. High doses of aspirin should not be taken with KEVEYIS.
  • KEVEYIS can cause your body to lose potassium, which can lead to heart problems. Your healthcare provider will measure the potassium levels in your blood before you start treatment and at certain times during treatment.
  • Tell your healthcare provider about all other prescription and over-the-counter medicines you take, including supplements, as some medicines can interact with KEVEYIS.
  • While taking KEVEYIS, your body may produce too much acid or may not be able to remove acid from the body. Your healthcare provider may run tests on a regular basis to check for signs of acid buildup.
  • KEVEYIS may increase your risk of falling. Tell your healthcare provider right away if you experience a fall while taking KEVEYIS.
  • The risks of falls and acid buildup are greater in elderly patients.
  • It is not known whether KEVEYIS is safe or effective for people younger than 18 years of age.

What are the most common side effects with KEVEYIS?

The most common side effects are a feeling of numbness, tingling or burning (“pins and needles”) in the toes, feet, hands or fingers; trouble with memory or thinking; feeling confused; and unpleasant taste in the mouth.

These are not all of the possible side effects of KEVEYIS. Call your healthcare provider for medical advice about side effects. You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.


  1. Data on file. Feasterville-Trevose, PA: Strongbridge Biopharma; 2017.
  2. Charles G, Zheng C, Lehmann-Horn F, Jurkat-Rott K, Levitt J. Characterization of hyperkalemic periodic paralysis: a survey of genetically diagnosed individuals. J Neurol. 2013;260:2606-2613.
  3. Cavel-Greant D, Lehmann-Horn F, Jurkat-Rott K. The impact of permanent muscle weakness on quality of life in periodic paralysis: a survey of 66 patients. Acta Myol. 2012;31:126-133.
  4. National Institutes of Health. Genetics Home Reference. Hyperkalemic periodic paralysis. https://ghr.nlm.nih.gov/condition/hyperkalemic-periodic-paralysis. Accessed December 5, 2016.
  5. National Institutes of Health. Genetics Home Reference. Hypokalemic periodic paralysis. https://ghr.nlm.nih.gov/condition/hypokalemic-periodic-paralysis. Accessed December 5, 2016.
  6. National Institutes of Health. Genetics Home Reference. Anderson-Tawil syndrome. https://ghr.nlm.nih.gov/condition/andersen-tawil-syndrome. Accessed December 5, 2016.
  7. National Institutes of Health. Genetics Home Reference. Potassium-aggravated myotonia. https://ghr.nlm.nih.gov/condition/potassium-aggravated-myotonia. Accessed December 5, 2016.
  8. National Institutes of Health. Genetics Home Reference. Paramyotonia congenita. https://ghr.nlm.nih.gov/condition/paramyotonia-congenita. Accessed December 5, 2016.
  9. Weber F, Jurkat-Rott K, Lehmann-Horn F. Hyperkalemic Periodic Paralysis. GeneReviews®. NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health. 2016.
  10. Vicart S, Sternberg D, Arzel-Hezode M, et al. Hypokalemic Periodic Paralysis. NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health. 2014.
  11. Fontaine B, Phillips LH 2nd. A newly approved drug for a rare group of diseases: dichlorphenamide for periodic paralysis. Neurology. 2016;86:1366-1367.
  12. Arya SN. Periodic paralysis. Journal, Indian Academy of Clinical Medicine. 2002;3:374-382.