Amiloride Systematic (IUPAC) name 3,5-diamino-6-chloro-N-(diaminomethylene)pyrazine-2-carboxamide Clinical data Trade names Midamor AHFS/Drugs.com 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 Identifiers CAS number ATC code C03 PubChem IUPHAR ligand DrugBank ChemSpider UNII KEGG ChEBI ChEMBL Chemical data Formula C6H8ClN7O Mol. mass 229.627 g/mol SMILES & (what is this?)
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 it's short time of action, therefore longer-acting ENaC inhibitors may prove more effective, e.g. Benzamil.
Mechanism of action
Amiloride works by directly blocking the epithelial sodium channel (ENaC) thereby inhibiting sodium reabsorption in the late distal convoluted tubules, connecting tubules, and collecting ducts in the kidneys (this mechanism is the same for triamterene). This promotes the loss of sodium and water from the body, but without depleting potassium. The drug is often used in conjunction with thiazide (e.g. co-amilozide) or loop diuretics (e.g. co-amilofruse). Due to its potassium-sparing capacities, hyperkalemia (high blood potassium levels) is occasionally observed in patients taking amiloride. The risk is high in concurrent use of ACE inhibitors or spironolactone. Patients are also advised not to use potassium-containing salt replacements. Amiloride also carries the risk of developing an acidosis.
A fraction of the effects of amiloride is inhibition of cyclic GMP-gated cation channels in the inner medullary collecting duct.
Amiloride has a second action on the heart, blocking Na+/H+ exchangers Sodium-hydrogen antiporter 1 or NHE-1. This minimizes reperfusion injury in ischemic attacks.
Formulations and trade names
- amiloride hydrochloride
- Midamor (U.S.)
- co-amilozide (amiloride hydrochloride with hydrochlorothiazide)
- ^ (Review)Pharmacological treatment of the biochemical defect in cystic fibrosis airways, H.C. Rodgers, A.J. Knoxhttp://erj.ersjournals.com/content/17/6/1314.full.pdf+html
- ^ Loffing, Johannes and Kaissling, Brigitte (2003). "Sodium and calcium transport pathways along the mammalian distal nephron: from rabbit to human". Am J Physiol Renal Physiol 284: F628-F643. PMID 12620920.
- ^ LoSalt Advisory Statement (PDF)
- ^ Walter F., PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. page 875
- ^ Hunt and Koltzenburg 2005 'The neurobiology of pain'
Channel blocker: sodium channel blockers ESC blocker Other/unknown/ungrouped Antihypertensives: diuretics (C03) Sulfonamides
(except EA)CA inhibitors (at PT)Thiazide-likes (primarily DCT)
Potassium-sparing (at CD)ESC blockers Osmotic diuretics (PT, DL) VAs (DCT and CD) Other This drug article relating to the cardiovascular system is a stub. You can help Wikipedia by expanding it.
- amiloride hydrochloride