Overview
11 DESCRIPTION Dichlorphenamide tablets USP contain dichlorphenamide, an oral carbonic anhydrase inhibitor. Dichlorphenamide USP, a dichlorinated benzenedisulfonamide, is known chemically as 4, 5– dichloro- 1,3-benzenedisulfonamide. Its empirical formula is C 6 H 6 Cl 2 N 2 O 4 S 2 and its structural formula is: Dichlorphenamide USP is a white or practically white crystalline powder with a...
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Dichlorphenamide is a carbonic anhydrase inhibitor. However, the precise mechanism by which dichlorphenamide exerts its therapeutic effects in patients with primary periodic paralysis is unknown. 12.2 Pharmacodynamics Dichlorphenamide can cause metabolic acidosis, which can increase the risk of salicylate toxicity with coadministration [see Warnings and Precautions ( 5.2 )] . Dichlorphenamide-induced metabolic acidosis can also increase in severity with coadministration of other drugs that cause metabolic acidosis [see Warnings and Precautions ( 5.4 )]. 12.
Indications
- 1 INDICATIONS AND USAGE Dichlorphenamide tablets are indicated for the treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants. Dichlorphenamide tablets are an oral carbonic anhydrase inhibitor indicated for the treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants ( 1 )
Common Doses
- 50 mg
- 200 mg
Dosage
2 DOSAGE AND ADMINISTRATION • Initiate dosing at 50 mg by mouth once or twice daily ( 2.1 ) • Titrate up or down dose based on individual response ( 2.1 ) • The minimum recommended dosage is 50 mg daily, and the maximum recommended dosage is 200 mg daily ( 2.1 ) • Evaluate response to dichlorphenamide tablets after 2 months of treatment ( 2.2 ) 2.1 Dosage Information Initiate dosing at 50 mg by mouth once or twice daily. The dosage may be increased or decreased based on individual response, at weekly intervals (or sooner in case of adverse reaction).
Contraindications
- 4 CONTRAINDICATIONS Dichlorphenamide is contraindicated in the following circumstances: Hypersensitivity to dichlorphenamide or other sulfonamides [see Warnings and Precautions ( 5.1 )] Concomitant use of dichlorphenamide and high dose aspirin [see Warnings and Precautions ( 5.2 ) and Drug Interactions ( 7.1 )] Severe pulmonary disease, limiting compensation to metabolic acidosis caused by dichlorphenamide [see Warnings and Precautions ( 5.4 )] Hepatic insufficiency: dichlorphenamide may aggravate hepatic encephalopathy.
Side Effects
- 6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in labeling: Hypersensitivity and Other Life-Threatening Reactions [see Warnings and Precautions ( 5.1 )] Hypokalemia [see Warnings and Precautions ( 5.3 )] Metabolic Acidosis [see Warnings and Precautions ( 5.4 )] Falls [ see Warnings and Precautions ( 5.5 )] Most common adverse reactions (incidence at least 10% and greater than placebo) include paresthesias, cognitive disorder, dysgeusia, and confusional state ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Rising Pharma Holdings, Inc.
Interactions
- 7 DRUG INTERACTIONS Aspirin: anorexia, tachypnea, lethargy, and coma have been reported with concomitant use of dichlorphenamide and high-dose aspirin. The concomitant use of dichlorphenamide tablets and high-dose aspirin is contraindicated. Dichlorphenamide tablets should be used with caution in patients receiving lower doses of aspirin ( 4 , 5.2 , 7.1 ) 7.1 Aspirin and Other Salicylates Carbonic anhydrase inhibitors, including dichlorphenamide, can cause metabolic acidosis [see Warnings and Precautions ( 5.2 , 5.4 )] , which can increase the risk of salicylate toxicity.