Dichlorphenamide (Keveyis) is a carbonic anhydrase inhibitor that is used in the treatment of patients with hypokalemic periodic paralysis.

Dichlorphenamide Uses:

• Primary periodic paralysis:
  • It is used for the treatment of primary hyperkalemic periodic paralysis and related variants.

Dichlorphenamide Dose in Adults:

Dichlorphenamide Dose in the Primary periodic paralysis:

• Oral :Initialy 50 my two times a day.
• It may increase or decrease dosage at weekly intervals or more frequently used in response to adverse reactions.
• Maximum: 200 mg per day.
• Assess the response and may be advised for continued therapy after two months of treatment.

Use in Children:

Not indicated.   

Pregnancy Risk Factor C

• Animal reproduction studies have shown that adverse events can be observed.
• Limited information is available on potassium management for primary periodic paralysis during pregnancy.

Dichlorphenamide use during breastfeeding:

• It is unknown if dichlorphenamide can be excreted from breast milk.
• The manufacturer suggests that nursing mothers exercise caution when using dichlorphenamide.

Dose in Kidney Disease:

There are no dosage adjustments provided in the manufacturer’s labeling.   

Dose in Liver disease:

Use is contraindicated.   

Common Side Effects of Dichlorphenamide:

• Central Nervous System:
  • Paresthesia
  • Cognitive dysfunction
  • Confusion
• Gastrointestinal:
  • Dysgeusia

Less Common Side Effects of Dichlorphenamide:

• Central Nervous System:
  • Fatigue
  • Headache
  • Hypoesthesia
  • Lethargy
  • Dizziness
  • Malaise
• Dermatologic:
  • Skin rash
  • Pruritus
• Endocrine & Metabolic:
  • Weight loss
• Gastrointestinal:
  • Diarrhea
  • Nausea
• Neuromuscular & Skeletal:
  • Muscle spasm
  • Arthralgia
  • Muscle twitching
• Respiratory:
  • Dyspnea
  • Pharyngolaryngeal pain

Contraindication to Dichlorphenamide Include:

• Allergy to dichlorphenamide or other sulfonamides
• severe pulmonary disease
• Hepatic insuffiency or any component of this formulation
• Concomitant use with high-dose Aspirin.

Warnings and precautions

• CNS depression:
  • CNS depression can lead to mental or physical impairments.
  • It is important to warn patients about tasks that require mental alertness, such as driving or operating machinery.
• Fall risk
  • Dichlorphenamide can increase the chance of falling, particularly in older patients or patients who are taking high doses.
  • Patients who have fallen should be considered for dose reductions or discontinuation.
• Hypokalemia
  • Hypokalemia can be caused by dichlorphenamide, which increases potassium excretion.
  • Patients with a history associated with hypokalemia, such as adrenocortical or respiratory insufficiency, hyperchloremic metabolism acidosis and respiratory acidosis, are at greater risk.
  • Hypokalemia can also be increased if the drug is taken with antifungals, loop diuretics and thiazide-diuretics, penicillin, penicillin, or theophylline.
  • Monitoring serum potassium is important at baseline and throughout treatment. If hypokalemia persists, discontinue or reduce dosage.
• Metabolic acidosis:
  • Hyperchloremia non-anion gap metabolic acidosis may occur.
  • Concomitant use medications that are associated with metabolic acidosis can increase the severity.
  • Monitoring serum sodium bicarbonate is important at baseline and every other day. If metabolic acidosis persists, discontinue or reduce dosage.
• Allergy to sulfonamide ("sulfa")
  • FDA-approved product labels for medications that contain a sulfonamide chemical groups include a wide contraindication for patients who have had an allergic reaction to sulfonamides in the past.
  • Cross-reactivity is possible between members of one class (eg two antibiotic sulfonamides).
  • Cross-reactivity concerns have been raised previously for all compounds with the sulfonamide structural (SO NH).
  • A deeper understanding of allergic mechanisms suggests that cross-reactivity between nonantibiotic and antibiotic sulfonamides is unlikely.
  • Nonantibiotic sulfonamides are not likely to cause anaphylaxis (cross-reactions due to antibody production).
  • T-cell-mediated (type IV), reactions (eg maculopapular skin rash) are less understood. It is difficult to exclude this possibility based on current knowledge.
  • Some clinicians opt to avoid these classes in cases of severe reactions (Stevens Johnson syndrome/TEN).
  • Stop using the product immediately if you notice a skin rash, or an immune-mediated adverse reaction. 2 2
• Hepatic impairment
  • Patients with liver impairment should not use this medication.

Dichlorphenamide: Drug Interaction

Note: Drug Interaction Categories:

• Risk Factor C: Monitor When Using Combination
• Risk Factor D: Consider Treatment Modification
• Risk Factor X: Avoid Concomitant Use

Monitoring parameters:

• Evaluate the treatment response after 2 months.
• Monitor serum potassium and serum sodium bicarbonate at baseline and periodically throughout treatment.   

How to administer?

It is administered orally after meals.   

Mechanism of action of Dichlorphenamide:

• Dichlorphenamide is an inhibitor of carbonic anhydrase. 
• It is not known how dichlorphenamide works in treating periodic paralysis patients.   

International Brands of Dichlorphenamide:

• Keveyis
• Antidrasi
• Barastonin
• Daranide
• Diclofenamid
• Fenamide
• Glajust
• Glaucol
• Glaumid
• Oratrol

Dichlorphenamide Brands Names in Pakistan:

No Brands Available in Pakistan.