Diclofenamide

Clinical data
AHFS/Drugs.com	International Drug Names
MedlinePlus	a601233
ATC code	S01EC02 (WHO) ;
Pharmacokinetic data
Protein binding	55%
Identifiers
	IUPAC name 4,5-Dichlorobenzene-1,3-disulfonamide;
CAS Number	120-97-8 ;
PubChem CID	3038;
IUPHAR/BPS	6807;
DrugBank	DB01144 ;
ChemSpider	2930 ;
UNII	VVJ6673MHY;
KEGG	D00518 ;
ChEBI	CHEBI:101085 ;
ChEMBL	ChEMBL17 ;
CompTox Dashboard (EPA)	DTXSID1022922 ;
ECHA InfoCard	100.004.037
Chemical and physical data
Formula	C6H6Cl2N2O4S2
Molar mass	305.14 g·mol−1
3D model (JSmol)	Interactive image;
Melting point	228.5 °C (443.3 °F)
	SMILES Clc1c(cc(cc1Cl)S(=O)(=O)N)S(=O)(=O)N;
	InChI InChI=1S/C6H6Cl2N2O4S2/c7-4-1-3(15(9,11)12)2-5(6(4)8)16(10,13)14/h1-2H,(H2,9,11,12)(H2,10,13,14) ; Key:GJQPMPFPNINLKP-UHFFFAOYSA-N ;
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Diclofenamide

Diclofenamide (or dichlorphenamide) is a sulfonamide and a carbonic anhydrase inhibitor of the meta-disulfamoylbenzene class. Dichlorphenamide as a carbonic anhydrase inhibitor is used for the treatment of acute angle closure glaucoma. While Dichlorphenamide does contain two sulfate groups within the structure, it falls under the class of a first generation carbonic anhydrase Inhibitor.

Uses

Diclofenamide was approved in the United States in 1958 as Daranide to treat glaucoma,[1][2][3] Subsequently, it was found effective in cases of therapy-resistant epilepsy.[4] In 2015, the medication was approved in the US under the name Keveyis as an orphan drug for the treatment of primary hypokalemic and hyperkalemic periodic paralysis.[1][5]

Cost

In 2001, diclofenamide had a U.S. list price of $50 for a bottle of 100 pills, and was approved for glaucoma. Merck discontinued diclofenamide when better glaucoma drugs were developed. In 2010, Sun Pharmaceutical Industries bought the rights.[citation needed] In 2015, the F.D.A. approved it as an orphan drug, with 7-year exclusive marketing rights, for periodic paralysis, which the company estimates affects 5,000 people in the U.S. In 2016, Strongbridge Biopharma acquired Sun, which raised the price to $15,001 for 100 pills. The cost of treatment would range from $109,500 to $219,000 a year. Sun gives the drug free to patients who don't have insurance.[5]

References

^ a b "Dichlorphenaide (Keveyis) for Periodic Paralysis". The Medical Letter. April 16, 2016. Retrieved December 19, 2017.
^ International Drug Names: Diclofenamide
^ Kanski JJ (August 1968). "Carbonic anhydrase inhibitors and osmotic agents in glaucoma. Carbonic anhydrase inhibitors". The British Journal of Ophthalmology. 52 (8): 642–3. doi:10.1136/bjo.52.8.642. PMC 506660. PMID 5724852.
^ Rucquoy M, Sorel L (1978). "Diclofenamide in the treatment of therapy-resistant epilepsy". Acta Neurologica Belgica. 78 (3): 174–82. PMID 352085.
^ a b Johnson CY (December 18, 2017). "This old drug was free. Now it's $109,500 a year". Washington Post.

[ML-1] "Dichlorphenaide (Keveyis) for Periodic Paralysis". The Medical Letter. April 16, 2016. Retrieved December 19, 2017.

[2] International Drug Names: Diclofenamide

[3] Kanski JJ (August 1968). "Carbonic anhydrase inhibitors and osmotic agents in glaucoma. Carbonic anhydrase inhibitors". The British Journal of Ophthalmology. 52 (8): 642–3. doi:10.1136/bjo.52.8.642. PMC 506660. PMID 5724852.

[4] Rucquoy M, Sorel L (1978). "Diclofenamide in the treatment of therapy-resistant epilepsy". Acta Neurologica Belgica. 78 (3): 174–82. PMID 352085.

[WP-5] Johnson CY (December 18, 2017). "This old drug was free. Now it's $109,500 a year". Washington Post.