Description and Brand Names

Drug information provided by: IBM Micromedex

US Brand Name

  1. Keveyis


Dichlorphenamide is used to treat inherited muscle disorders, such as primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants. This medicine is a carbonic anhydrase inhibitor.

This medicine is available only with your doctor's prescription.

This product is available in the following dosage forms:

  • Tablet

Before Using

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of dichlorphenamide in the pediatric population. Safety and efficacy have not been established.


Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of dichlorphenamide in the elderly. However, elderly patients are more likely to have falls or metabolic acidosis, which may require caution in patients receiving dichlorphenamide.


There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

  • Aspirin

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Acyclovir
  • Adefovir
  • Furosemide
  • Valacyclovir

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Adrenal problems or
  • Hyperchloremic metabolic acidosis or
  • Respiratory acidosis—May increase risk for hypokalemia.
  • Allergy to sulfa drugs or
  • Liver disease or
  • Lung disease, severe—Should not be used in patients with these conditions.

Proper Use

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects.


The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (tablets):
    • For primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants:
      • Adults—At first, 50 milligrams (mg) two times a day. Your doctor may increase your dose as needed. However, the dose is usually not more than 200 mg per day.
      • Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.


Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.


It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects.

Do not use this medicine together with high-dose aspirin. Using these medicines together may cause unwanted effects.

This medicine may cause serious allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Check with your doctor right away if you have blistering, peeling, or red skin rash, fever with or without chills, itching skin, lower back or side pain, painful or difficult urination, sore throat, sores, ulcers, or white spots on the lips or in the mouth, unusual bleeding or bruising, or yellow eyes or skin.

Check with your doctor if you have convulsions, dry mouth, increased thirst, muscle pain or cramps, nausea or vomiting, numbness or tingling in the hands, feet, or lips, or uneven heartbeat. These may be symptoms of hypokalemia.

This medicine may cause some people to feel drowsy or more tired than they are normally. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Incidence not known

  1. Abdominal or stomach pain
  2. black, tarry stools
  3. blistering, peeling, or loosening of the skin
  4. chest pain or discomfort
  5. chills
  6. confusion
  7. convulsions
  8. cough or hoarseness
  9. dark urine
  10. decreased urine
  11. diarrhea
  12. dilated neck veins
  13. dizziness
  14. drowsiness
  15. dry mouth
  16. extreme fatigue
  17. fever with or without chills
  18. general feeling of tiredness or weakness
  19. headache
  20. increased thirst
  21. irregular breathing
  22. irregular heartbeat
  23. itching or rash
  24. joint or muscle pain
  25. light-colored stools
  26. loss of appetite
  27. lower back or side pain
  28. mood changes
  29. muscle pain or cramps
  30. nausea or vomiting
  31. numbness or tingling in the hands, feet, or lips
  32. painful or difficult urination
  33. rapid, deep breathing
  34. red skin lesions, often with a purple center
  35. red, irritated eyes
  36. restlessness
  37. sore throat
  38. sores, ulcers, or white spots in the mouth or on the lips
  39. stomach cramps
  40. swelling of the face, fingers, feet, or lower legs
  41. swollen or painful glands
  42. tightness in the chest
  43. unpleasant breath odor
  44. unusual bleeding or bruising
  45. unusual tiredness or weakness
  46. vomiting of blood
  47. weight gain
  48. yellow eyes or skin

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

  1. Bloody or cloudy urine
  2. bloody, black, or tarry stools
  3. burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  4. continuing ringing or buzzing or other unexplained noise in the ears
  5. difficult or painful urination
  6. fainting
  7. hearing loss
  8. high fever
  9. pale skin
  10. shakiness and unsteady walk
  11. shakiness in the legs, arms, hands, or feet
  12. sudden decrease in the amount of urine
  13. unsteadiness, trembling, or other problems with muscle control or coordination

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  1. Burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  2. change in taste
  3. difficulty with moving
  4. general feeling of discomfort or illness
  5. loss of taste
  6. muscle pain or stiffness
  7. muscle spasms
  8. muscle twitching
  9. pain in the joints
  10. trouble performing routine tasks
  11. unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness

Incidence not known

  1. Decreased awareness or responsiveness
  2. loss of memory
  3. problems with memory
  4. seeing, hearing, or feeling things that are not there
  5. severe sleepiness

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

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