Mechanism of effect
Dichlorphenamide is a carbonic anhydrase inhibitor; the mechanism by which dichlorphenamide exerts its therapeutic effects in patients with periodic paralysis is unknown
Pharmacodynamic
Time to Peak
1.5
to 3 hours
Half-Life Elimination
Terminal: 32 to 66 hours
1.5
to 3 hours
Half-Life Elimination
Terminal: 32 to 66 hours
Drug indications
Primary periodic paralysis: Treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants
Dosage
Usual Adult Dose for Primary Periodic Paralysis
Initial dose: 50 mg orally 2 times a day; the initial dose may be increased or decreased based on individual response, at weekly intervals (or sooner in case of adverse reaction
-Maximum dose: 200 mg orally per day
Initial dose: 50 mg orally 2 times a day; the initial dose may be increased or decreased based on individual response, at weekly intervals (or sooner in case of adverse reaction
-Maximum dose: 200 mg orally per day
Drug contraindications
Hypersensitivity to dichlorphenamide, other sulfonamides, or any component of the formulation; concomitant use with high-dose aspirin; severe pulmonary disease; hepatic insufficiency
Side effects
>10%
Central nervous system: Paresthesia, cognitive dysfunction, confusion
Gastrointestinal: Dysgeusia
1%
to 10%
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
Frequency not defined: Central nervous system: Difficulty thinking, disturbance in attention
Postmarketing: Amnesia, cardiac failure, hallucination, increased severity of condition, nephrolithiasis, pancytopenia, psychosis, renal tubular necrosis, seizure, stupor, syncope, tremor
Central nervous system: Paresthesia, cognitive dysfunction, confusion
Gastrointestinal: Dysgeusia
1%
to 10%
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
Frequency not defined: Central nervous system: Difficulty thinking, disturbance in attention
Postmarketing: Amnesia, cardiac failure, hallucination, increased severity of condition, nephrolithiasis, pancytopenia, psychosis, renal tubular necrosis, seizure, stupor, syncope, tremor
Interactions
Dofetilide , Decitabine , Dexlansoprazole , Treprostinil , Amantadine , Amphotericin B , Interferon gamma-1b , Brinzolamide , Primidone , Theophyline , Aminosalicylic Acid , Methenamine , Felbamate , Fosphenytoin , Trientine , sodium phosphates , Glucagon , Ammonium chloride , Vitamin A , Flecainide , oseltamivir , Methazolamide , Quinidine , carfilzomib , Tretinoin , Famotidin , Fludarabine phosphate , Phenytoin , Methotrexate , MemantineAlpha-/Beta-Agonists (Indirect-Acting), Amantadine, Amphetamines, Amphotericin B,
Antifungal Agents (Azole Derivatives, Systemic), CarBAMazepine, Carbonic Anhydrase Inhibitors, Diacerein, Famotidine, Flecainide, Fosphenytoin-Phenytoin, Laxatives, Lithium,
Loop Diuretics, Memantine, MetFORMIN, Methenamine, Methotrexate, OAT1/3 Inhibitors,
Opioid Agonists, Oseltamivir, Penicillins, Primidone, QuiNIDine, Salicylates, Sodium Phosphates,
Theophylline, Thiazide and Thiazide-Like Diuretics, Trientine
Antifungal Agents (Azole Derivatives, Systemic), CarBAMazepine, Carbonic Anhydrase Inhibitors, Diacerein, Famotidine, Flecainide, Fosphenytoin-Phenytoin, Laxatives, Lithium,
Loop Diuretics, Memantine, MetFORMIN, Methenamine, Methotrexate, OAT1/3 Inhibitors,
Opioid Agonists, Oseltamivir, Penicillins, Primidone, QuiNIDine, Salicylates, Sodium Phosphates,
Theophylline, Thiazide and Thiazide-Like Diuretics, Trientine
Alerts
Avoid using dichlorphenamide if you are pregnant. Dichlorphenamide may cause metabolic acidosis, which could harm an unborn baby if you have this condition during pregnancy
dichlorphenamide may cause blurred vision and may impair your reactions. Avoid driving or hazardous activity until you know how this medicine will affect you
Safety and efficacy have not been established in patients younger than 18 years
May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving
Dichlorphenamide increases potassium excretion and may cause hypokalemia; risk is increased in patients with a history of conditions associated with hypokalemia (eg, adrenocortical excess, renal tubular acidosis type 1 and 2) and coadministration with medications associated with hypokalemia (eg, loop diuretics, thiazide diuretics, laxative, antifungals, penicillin, theophylline). Monitor serum potassium at baseline and periodically throughout treatment; discontinue use or reduce the dose if hypokalemia develops or persists and correct potassium levels
dichlorphenamide may cause blurred vision and may impair your reactions. Avoid driving or hazardous activity until you know how this medicine will affect you
Safety and efficacy have not been established in patients younger than 18 years
May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks that require mental alertness (eg, operating machinery or driving
Dichlorphenamide increases potassium excretion and may cause hypokalemia; risk is increased in patients with a history of conditions associated with hypokalemia (eg, adrenocortical excess, renal tubular acidosis type 1 and 2) and coadministration with medications associated with hypokalemia (eg, loop diuretics, thiazide diuretics, laxative, antifungals, penicillin, theophylline). Monitor serum potassium at baseline and periodically throughout treatment; discontinue use or reduce the dose if hypokalemia develops or persists and correct potassium levels
Points of recommendation
You should not use dichlorphenamide if you are allergic to it, or if you have
severe breathing problems
liver disease
an allergy to sulfa drugs
if you also take aspirin in high doses
Tell your doctor if you have ever had
metabolic acidosis (high levels of acid in your blood
an electrolyte imbalance (such as low levels of potassium or magnesium in your blood
Call your doctor at once if you have accidental falls while taking dichlorphenamide. Your dose may need to be changed
You may need medical tests to help your doctor determine how long to treat you with dichlorphenamide
Store at room temperature away from moisture and heat
Overdose symptoms may include dizziness, drowsiness, vomiting, loss of appetite, tremors, loss of balance or coordination, or ringing in your ears
severe breathing problems
liver disease
an allergy to sulfa drugs
if you also take aspirin in high doses
Tell your doctor if you have ever had
metabolic acidosis (high levels of acid in your blood
an electrolyte imbalance (such as low levels of potassium or magnesium in your blood
Call your doctor at once if you have accidental falls while taking dichlorphenamide. Your dose may need to be changed
You may need medical tests to help your doctor determine how long to treat you with dichlorphenamide
Store at room temperature away from moisture and heat
Overdose symptoms may include dizziness, drowsiness, vomiting, loss of appetite, tremors, loss of balance or coordination, or ringing in your ears
Pregnancy level
Data are not available on the developmental risk associated with the use in pregnant women
Breast feeding warning
Unknown if distributed in human breast milk
Drug forms
Keveyis, Daranide
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