Title: Amiloride
CAS Registry Number: 2609-46-3
CAS Name: 3,5-Diamino-N-(aminoiminomethyl)-6-chloropyrazinecarboxamide
Additional Names: N-amidino-3,5-diamino-6-chloropyrazinecarboxamide; N-amidino-3,5-diamino-6-chloropyrazinamide; 1-(3,5-diamino-6-chloropyrazinecarboxyl)guanidine; 1-(3,5-diamino-6-chloropyrazinoyl)guanidine; guanamprazine; amipramidin; amipramizide
Molecular Formula: C6H8ClN7O
Molecular Weight: 229.63
Percent Composition: C 31.38%, H 3.51%, Cl 15.44%, N 42.70%, O 6.97%
Literature References: Sodium channel blocker. Prepn: E. J. Cragoe, Jr., BE 639386; idem, US 3313813 (1964, 1967 both to Merck & Co.). NMR study on tautomerism and conformation: R. L. Smith et al., J. Am. Chem. Soc. 101, 191 (1979). Pharmacology: Baer et al., J. Pharmacol. Exp. Ther. 157, 472 (1967); Baba et al., Clin. Pharmacol. Ther. 9, 318 (1968); Lant et al., ibid. 10, 50 (1969). Metabolism: Weiss et al., ibid. 401. Clinical evaluation in cystic fibrosis: M. R. Knowles et al., N. Engl. J. Med. 322, 1189 (1990); in combination with uridine 5¢-triphosphate, q.v.: W. D. Bennett et al., Am. J. Respir. Crit. Care Med. 153, 1796 (1996). Reviews: H. L. Macfie et al., Drug Intell. Clin. Pharm. 15, 94-98 (1981); D. E. Hyams, Int. Congr. Symp. Ser. - R. Soc. Med. 44, 65-73 (1981). Comprehensive description of hydrochloride: D. J. Mazzo, Anal. Profiles Drug Subs. 15, 1-34 (1986). Review of mechanism of action: T. R. Kleyman, E. J. Cragoe, Jr., Semin. Nephrol. 8, 242-248 (1988).
Properties: Solid, mp 240.5-241.5°.
Melting point: mp 240.5-241.5°
Derivative Type: Hydrochloride dihydrate
CAS Registry Number: 17440-83-4
Manufacturers' Codes: MK-870
Trademarks: Amikal (GEA); Midamor (Merck & Co.); Modamide (Merck & Co.)
Molecular Formula: C6H8ClN7O.HCl.2H2O
Molecular Weight: 302.12
Percent Composition: C 23.85%, H 4.34%, Cl 23.47%, N 32.45%, O 15.89%
Properties: Crystalline solid, dec 285-288°. Anhydr, mp 293.5°. uv max (water): 212, 285, 362 nm (E1%1cm 642, 555, 617). pKa 8.7. Freely sol in DMSO, slightly sol in water, isopropanol, ethanol. Practically insol in acetone, chloroform, diethyl ether, ethyl acetate.
Melting point: mp 293.5°
pKa: pKa 8.7
Absorption maximum: uv max (water): 212, 285, 362 nm (E1%1cm 642, 555, 617)
Derivative Type: Hydrochloride dihydrate mixture with hydrochlorothiazide
Additional Names: Co-amilozide
Trademarks: Amil-Co (Baker Norton); Aquaretic (Azupharma); Ecodurex (Ecosol); Grodurex (Grossmann); Hexarese (Durascan); Moduretic (Merck & Co.); Moduretik (Merck & Co.); Normetic (Abbott); Normorix (Nycomed)
Therap-Cat: Diuretic.
Keywords: Diuretic.
Aminacrine Amine 220 Amineptine Aminitrozole Aminoacetonitrile

Systematic (IUPAC) name
Clinical data
Trade names Midamor
AHFS/ monograph
Pregnancy cat. B (US)
Legal status -only (US)
Routes oral
Pharmacokinetic data
Bioavailability Readily absorbed
Metabolism none
Half-life 6 to 9 hours
Excretion unchanged in urine
CAS number 2016-88-8 YesY
ATC code C03DB01
PubChem CID 16231
IUPHAR ligand 2421
DrugBank DB00594
ChemSpider 15403 YesY
UNII 7M458Q65S3 YesY
KEGG D07447 YesY
Chemical data
Formula C6H8ClN7O 
Mol. mass 229.627 g/mol
 YesY (what is this?)  (verify)

Amiloride is a potassium-sparing diuretic, first approved for use in 1967 (then known as MK 870), used in the management of hypertension and congestive heart failure. Amiloride was also tested as treatment of cystic fibrosis, but it was revealed inefficient in vivo due to its short time of action, therefore longer-acting ENaC inhibitors may prove more effective, e.g. Benzamil.[1]