Dichlorphenamide is a medication used primarily in the treatment of glaucoma and a rare disorder called periodic paralysis. It belongs to a class of drugs known as carbonic anhydrase inhibitors. These drugs work by decreasing the production of fluid inside the eye, thereby reducing intraocular pressure, which is beneficial in treating glaucoma.

In addition to its use in glaucoma, dichlorphenamide is also prescribed for the management of periodic paralysis, a condition characterized by episodes of muscle weakness or paralysis. In periodic paralysis, dichlorphenamide helps regulate potassium levels in the body, which can reduce the frequency and severity of attacks.

Dichlorphenamide (Keveyis), a carbonic anhydrase inhibitor which is used in the therapy of patients with hypokalemic periodic paralysis.

Dichlorphenamide Uses:

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

Dichlorphenamide Dose in Adults:

Dichlorphenamide Dose in Primary periodic paralysis:

• In primary periodic paralysis, the starting dose of dichlorphenamide taken by mouth is usually 50 milligrams two times a day.
• Your doctor may adjust this dose up or down every week or even more often if needed, based on how you're responding to the medicine or if you're having any side effects.
• The most you should take in one day is 200 milligrams.
• Your doctor will check how you're doing after about two months to see if you still need to keep taking the medicine.

Use in Children:

Not indicated.   

Pregnancy Risk Factor C

• During pregnancy, dichlorphenamide has a pregnancy risk factor of C, meaning that while adverse events have been observed in animal studies, there isn't enough information about its effects on pregnancy in humans.
• Specifically, details regarding potassium management for primary periodic paralysis during pregnancy are scarce.

Dichlorphenamide use during breastfeeding:

• It's uncertain whether dichlorphenamide passes into breast milk.
• Therefore, the manufacturer advises caution when giving dichlorphenamide to breastfeeding women.

Dose in Kidney Disease:

• The manufacturer's labeling for dichlorphenamide does not include any specific dosage adjustments for people with renal impairment.
• This is because studies on how the medication affects individuals with kidney problems have not been conducted.

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

Contraindications to Dichlorphenamide Include:

• Dichlorphenamide should not be used if you have a known hypersensitivity to dichlorphenamide itself, other sulfonamide medications, or any ingredient in the formulation.
• Additionally, it is not recommended to use dichlorphenamide concurrently with high doses of aspirin.
• People with severe pulmonary disease or liver problems should also avoid using dichlorphenamide.

Warnings and precautions

CNS depression:

• Dichlorphenamide may cause central nervous system (CNS) depression, which can impair physical or mental abilities.
• Patients should be warned about engaging in activities that require mental alertness, such as driving or operating machinery, while taking this medication.

Fall risk

• Taking dichlorphenamide increases the risk of falling, particularly in older adults and those taking high doses.
• If a patient experience falls while using dichlorphenamide, healthcare providers should consider reducing the dosage or discontinuing the medication altogether.
• Falls can lead to serious injuries, so it's important for patients and caregivers to be aware of this risk and take precautions to prevent falls, such as installing handrails, using assistive devices, and being cautious when moving around.

Hypokalemia

• Dichlorphenamide can increase the loss of potassium from the body, which may lead to hypokalemia (low potassium levels).
• The risk of hypokalemia is higher in patients with a history of conditions associated with low potassium levels, such as adrenocortical insufficiency, hyperchloremic metabolic acidosis, or respiratory acidosis.
• Additionally, using dichlorphenamide alongside medications that also lower potassium levels, like loop diuretics, thiazide diuretics, laxatives, antifungals, penicillin, or theophylline, can further increase this risk.

Metabolic acidosis:

• Dichlorphenamide can lead to a type of metabolic acidosis known as hyperchloremic nonanion gap metabolic acidosis.
• This risk can be heightened when dichlorphenamide is used alongside other medications that are also associated with metabolic acidosis.

Allergy to sulfonamide ("sulfa")

• Patients with a history of allergic reactions to sulfonamides, often referred to as "sulfa" allergies, may be concerned about using medications containing a sulfonamide chemical group like dichlorphenamide.
• While traditional understanding warned against using any sulfonamide-containing medication in these patients due to the risk of cross-reactivity, newer research suggests that the risk may be lower than previously thought.
• Specifically, the risk of cross-reactivity between antibiotic sulfonamides and nonantibiotic sulfonamides, like dichlorphenamide, may be minimal.
• Allergic reactions involving antibody production, such as anaphylaxis, are unlikely with nonantibiotic sulfonamides.
• However, T-cell-mediated reactions like maculopapular rash are less understood, and some caution is warranted.
• If a severe allergic reaction such as Stevens-Johnson syndrome or toxic epidermal necrolysis occurs, discontinuation of the medication is recommended.

Hepatic impairment

• Dichlorphenamide should not be used in patients with hepatic impairment.
• This means individuals with liver problems should avoid taking this medication altogether.

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:

Response Evaluation:

• Your healthcare provider will check how you're doing after about two months of taking dichlorphenamide to see how well it's working for you.

Monitoring:

• Serum Potassium Levels:
  • Your healthcare provider will measure your potassium levels in your blood before starting dichlorphenamide and regularly throughout your treatment.
• Serum Sodium Bicarbonate:
  • Similarly, your healthcare provider will also check the levels of sodium bicarbonate in your blood before starting the medication and periodically during your treatment.

How to administer?

It is administered orally after meals.   

Mechanism of action of Dichlorphenamide:

• Dichlorphenamide is a type of medication called a carbonic anhydrase inhibitor.
• It's used to treat periodic paralysis, but how exactly it works to help patients with this condition is not fully understood.
• While the mechanism behind dichlorphenamide's therapeutic effects in periodic paralysis remains unclear, it's believed to involve its action on certain processes in the body related to muscle function and potassium levels.
• Further research is needed to fully understand how dichlorphenamide benefits individuals with periodic paralysis.

International Brands of Dichlorphenamide:

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

Dichlorphenamide Brands Names in Pakistan:

Not Available.