Article: Furosemide

Furosemide
Systematic (IUPAC) name
5-(aminosulfonyl)-4-chloro-2- [(2-furanylmethyl)amino]benzoic acid
Identifiers
CAS number	54-31-9
ATC code	C03CA01
PubChem	162482
DrugBank	APRD00608
Chemical data
Formula	C12H11N2ClO5S
Mol. weight	330.745
Pharmacokinetic data
Bioavailability	43-69%
Metabolism	hepatic and renal glucuronidation
Half life	up to 100 minutes
Excretion	renal 66%, biliary 33%
Therapeutic considerations
Pregnancy cat.	C(AU) C(US)
Legal status	℞ Prescription only
Routes	Oral, IV, IM

Furosemide (INN) or frusemide (former BAN) is a loop diuretic used in the treatment of congestive heart failure and edema. It is most commonly marketed by Aventis Pharma under the brand name Lasix. It has also been used to prevent thoroughbred race horses from bleeding through the nose during races.

Along with some other diuretics, furosemide is also included on the World Anti-Doping Agency's banned drug list due to its alleged use as a masking agent for other drugs.

Mechanism of action

Main article: Loop diuretic

Like other loop diuretics, furosemide acts by inhibiting the Na-K-2Cl symporter in the thick ascending loop of Henle. It also has inhibitory activity on carbonic anhydrase.

Clinical use in humans

Furosemide, as a loop diuretic, is principally used in the following indications (Aventis, 1998):

• Edema associated with heart failure, hepatic cirrhosis, renal impairment, nephrotic syndrome
• Hypertension
• Adjunct in cerebral/pulmonary edema where rapid diuresis is required (IV injection)

It is also sometimes used in the management of severe hypercalcemia in combination with adequate rehydration (Rossi, 2004).

Although disputed,^[1] it is considered ototoxic: "usually with large parenteral doses and rapid administration and in renal impairment"^[2]

Drug Interactions

Furosemide has potential interactions with the following medications:[1]

• Aminoglycoside antibiotics such as Garamycin
• Aspirin and other salicylates
• Other diuretics (e.g. Ethacrynic acid)
• Indomethacin
• Lithium
• Synergistic effects with other antihypertensives (e.g. Doxazosin)
• Sucralfate

Use in horses

Apparently, sometime in the early 1970s, furosemide's ability to prevent or at least greatly reduce the incidence of bleeding by horses during races was discovered accidentally. Pursuant to the racing rules of most states, horses that bleed from the nostrils three times are permanently barred from racing (for their own protection). Clinical trials followed, and by decade's end, racing commissions in some states began legalizing its use on race horses. On September 1, 1995, New York became the last state in the United States to approve such use, after years of refusing to consider doing so. Some states allow its use for all racehorses; some allow it only for confirmed "bleeders." Its use for this purpose is still prohibited in many other countries, however.

Brand names

Some of the brand names under which furosemide is marketed include: Aisemide®, Beronald®, Desdemin®, Discoid®, Diural®, Diurapid®, Dryptal®, Durafurid®, Errolon®, Eutensin®, Frusetic®, Frusid®, Fulsix®, Fuluvamide®, Furesis®, Furo-Puren®, Furosedon®, Hydro-rapid®, Impugan®, Katlex®, Lasilix®, Lasix®, Lodix®, Lowpston®, Macasirool®, Mirfat®, Nicorol®, Odemase®, Oedemex®, Profemin<®, Rosemide®, Rusyde®, Salix®, Trofurit®, Urex® Founded around 1964.

References

• Aventis Pharma (1998). Lasix Approved Product Information. Lane Cove: Aventis Pharma Pty Ltd.
• Rossi S (Ed.) (2004). Australian Medicines Handbook 2004. Adelaide: Australian Medicines Handbook. ISBN 0-9578521-4-2.

Footnotes

1. ^ Rais-Bahrami K, Majd M, Veszelovszky E, Short B (2004). "Use of furosemide and hearing loss in neonatal intensive care survivors.". Am J Perinatol 21 (6): 329-32. PMID 15311369.
2. ^ BNF 45 March 2003