Title: Cyclothiazide
CAS Registry Number: 2259-96-3
CAS Name: 3-Bicyclo[2.2.1]hept-5-en-2-yl-6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide
Additional Names: 6-chloro-3,4-dihydro-3-(2-norbornen-5-yl)-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide; 6-chloro-3,4-dihydro-3-(2-norbornen-5-yl)-7-sulfamoyl-1,2,4-benzothiadiazine 1,1-dioxide; 6-chloro-3-(2-norbornen-5-yl)-7-sulfamyl-3,4-dihydro-1,2,4-benzothiadiazine 1,1-dioxide
Manufacturers' Codes: Lilly 35483
Trademarks: Aquirel; Anhydron (Lilly); Doburil (Boehringer, Ing.); Fluidil (Adria)
Molecular Formula: C14H16ClN3O4S2
Molecular Weight: 389.88
Percent Composition: C 43.13%, H 4.14%, Cl 9.09%, N 10.78%, O 16.41%, S 16.45%
Literature References: Prepn: C. W. Whitehead et al., J. Org. Chem. 26, 2814 (1961); E. Müller, K. Hasspacher, US 3275625 (1966 to Boehringer, Ing.). Comprehensive description: C. D. Wentling, Anal. Profiles Drug Subs. 1, 65-77 (1972).
Properties: Crystals from dil alc, mp 234°.
Melting point: mp 234°
Therap-Cat: Diuretic; antihypertensive.
Therap-Cat-Vet: Diuretic.
Keywords: Antihypertensive; Thiazides and Analogs; Diuretic; Thiazides and Analogs.
Cyclovalone Cycothiamin(e) Cycrimine Hydrochloride Cyfluthrin Cyhalothrin

Systematic (IUPAC) name
3-(bicyclo[2.2.1]hept-5-en-2-yl)-6-chloro-3,4-dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide
Clinical data
Legal status Prescription only
CAS number 2259-96-3 YesY
ATC code C03AA09
PubChem CID 2910
DrugBank DB00606
ChemSpider 4535011 N
KEGG D01256 YesY
Chemical data
Formula C14H16ClN3O4S2 
Mol. mass 389.88 g/mol
 N (what is this?)  (verify)

Cyclothiazide (Anhydron, Acquirel, Doburil, Fluidil, Renazide, Tensodiural, Valmiran) is a benzothiadiazide (thiazide) diuretic and antihypertensive that was originally introduced in the United States in 1963 by Eli Lilly and was subsequently also marketed in Europe and Japan.[1][2] Related drugs include diazoxide, hydrochlorothiazide, and chlorothiazide.[3]

In 1993, it was discovered that cyclothiazide is a positive allosteric modulator of the AMPA receptor, capable of reducing or essentially eliminating rapid desensitization of the receptor, and potentiating glutamate currents by as much as 18-fold at the highest concentration tested (100 μM).[3][4][5][6] Additionally, in 2003, cyclothiazide was also found to act as a GABAA receptor negative allosteric modulator, potently inhibiting GABAA-mediated currents.[7] In animals it is a powerful convulsant, robustly enhancing epileptiform activity and inducing seizures, but without producing any apparent neuronal death.[8][9]