Cardiovascular Medicine Book


Potassium-Sparing Diuretic

Aka: Potassium-Sparing Diuretic, Amiloride, Midamor, Triamterene, Dyrenium
  1. Indications: Potassium-Sparing Diuretics only (Aldosterone independent, Amiloride and Triamterene)
    1. Hypertension
      1. Weak Diuretics primarily used to counter urinary Potassium loss with other Diuretics
  2. Indications: Aldosterone Antagonists (Spironolactone, Eplerenone)
    1. Congestive Heart Failure
      1. Counter Aldosterone adverse effects on myocardial remodeling
  3. Mechanism
    1. Weak Diuretics (compared with Loop Diuretics or Thiazide Diuretics)
    2. Potassium-Sparing Diuretics only
      1. Primarily used to counter urinary Potassium loss with other Diuretics
      2. Act directly at the distal convoluted tubule (Aldosterone independent)
        1. Increase Sodium excretion
        2. Decrease Potassium secretion
    3. Aldosterone Antagonists (Spironolactone and Eplerenone)
      1. Commonly used as adjunctive in Congestive Heart Failure management
      2. Counter Aldosterone adverse effects on myocardial remodeling
  4. Preparations: Potassium-Sparing Diuretics only (Aldosterone independent)
    1. Amiloride (Midamor)
      1. Dose: 5 mg orally daily (maximum: 20 mg/day)
      2. Renal excretion (unchanged in urine)
      3. Half-Life: 6 hours
    2. Triamterene (Dyrenium)
      1. Dose: 100 mg orally twice daily (maximum: 300 mg/day)
      2. Typically used as Combination Medication with Thiazide Diuretic
      3. Rapidly absorbed, highly metabolized in liver and Kidney and rapidly excreted
  5. Preparations: Potassium-Sparing Diuretic and Aldosterone Antagonists
    1. Spironolactone (Aldactone)
    2. Eplerenone (Inspra)
  6. Precautions
    1. Monitor Serum Potassium after starting a Potassium-Sparing Diuretic in those at Hyperkalemia risk
      1. Obtain Serum Potassium at 3 days, 7 days and then monthly for the first 3 months
  7. Adverse Effects: Potassium-Sparing Diuretics (Amiloride and Triamterene)
    1. Hyperkalemia
      1. Risk factors
        1. Renal Insufficiency
        2. Concurrent use with agents that raise Potassium (e.g. ACE Inhibitors, Potassium supplements)
    2. Blue Urine Color
      1. Specific to Triamterene
    3. Decreased renal perfusion (if Sodium and water depletion)
    4. Glucose Intolerance
      1. Potassium-Sparing Diuretics
  8. Drug Interactions
    1. Potassium supplements (risk of Hyperkalemia)
  9. References
    1. Olson (2020) Clinical Pharmacology, Medmaster, Miami, p. 62-3
    2. Hamilton (2010) Tarason Pocket Pharmacopeia, p. 100
Medication Costs
Triamterene-HCTZ (on 6/18/2017 at
Triamterene-HCTZ 37.5mg-25mg #30 tablets for $4.00 $0.13 each
Triamterene-HCTZ 37.5mg-25mg #90 tablets for $10.00 $0.11 each
Triamterene-HCTZ 75mg-50mg #30 tablets for $4.00 $0.13 each
Triamterene-HCTZ 75mg-50mg #90 tablets for $10.00 $0.11 each
amiloride (on 5/17/2017 at Medicaid.Gov Pharmacy Drug pricing)
AMILORIDE HCL 5 MG TABLET Generic $0.48 each
triamterene (on 5/17/2017 at Medicaid.Gov Pharmacy Drug pricing)
FPNotebook does not benefit financially from showing this medication data or their pharmacy links. This information is provided only to help medical providers and their patients see relative costs. Insurance plans negotiate lower medication prices with suppliers. Prices shown here are out of pocket, non-negotiated rates. See Needy Meds for financial assistance information.

Amiloride (C0002502)

Definition (NCI) A synthetic pyrazine derivative with antikaliuretic and diuretic properties. Amiloride inhibits sodium channels located in the distal tubules and collecting ducts of the kidney, thereby preventing the absorption of sodium and increasing its excretion along with water, to produce naturesis. In response to the hypernatremic conditions in the kidney, the plasma membrane becomes hyperpolarized and electrochemical forces are reduced, which then prevents the excretion of potassium and hydrogen into the lumen.
Definition (CSP) pyrazine compound inhibiting sodium reabsorbtion through sodium channels in renal epithelial cells; used in conjunction with diuretics to spare potassium loss.
Definition (MSH) A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D000584
SnomedCT 387503008, 87395005
LNC LP16024-9, MTHU006775
English Amiloride, Pyrazinecarboxamide, 3,5-diamino-N-(aminoiminomethyl)-6-chloro-, Amiloride [Chemical/Ingredient], aMILoride, AMILORIDE, amiloride, Amipramizide, Amiloride (product), Amiloride (substance)
Swedish Amilorid
Czech amilorid
Finnish Amiloridi
Polish Amiloryd
Japanese アミロライド, アミパミジン, アミロラジド, アミロリド
Spanish amilorida (producto), amilorida (sustancia), amilorida, Amilorida
French Amiloride
German Amilorid
Italian Amiloride
Portuguese Amilorida
Derived from the NIH UMLS (Unified Medical Language System)

Midamor (C0026054)

Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D000584
English midamor, Cahill May Roberts Brand of Amiloride Hydrochloride, Merck Brand of Amiloride Hydrochloride, Merck Sharp & Dohme Brand of Amiloride Hydrochloride, Modamide, Midamor
Derived from the NIH UMLS (Unified Medical Language System)

Triamterene (C0040869)

Definition (MSH) A pteridinetriamine compound that inhibits SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS.
Definition (NCI) A pteridine derivative with potassium-sparing diuretic property. Triamterene blocks the sodium-potassium exchange pump (Na-K-ATPase) in the luminal membrane of principal cells in the late distal tubule, cortical collecting tubule and collecting duct in the kidney. This reversible inhibition of the electrogenic sodium transport decreases the lumen-negative transepithelial potential difference and thus reduces the driving force for K+ movement into the tubular lumen resulting in the inhibition of sodium reabsorption in exchange for K+ and H+.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D014223
SnomedCT 12512008, 387053007
LNC LP14734-5, MTHU001919
English Triamterene, 2,4,7-Pteridinetriamine, 6-phenyl-, triamterene, triamterene (medication), TRIAMTERENE, Triamterene [Chemical/Ingredient], 6-Phenyl-2,4,7-triaminopteridine, 6-Phenyl-2,4,7-pteridinetriamine, Triamterene (product), Triamterene (substance)
Swedish Triamteren
Czech triamteren
Finnish Triamtereeni
Japanese トリアムテレン
Polish Triamteren
Spanish triamtereno (producto), triamtereno (sustancia), triamtereno, Triantereno
French Triamtérène
German Triamteren
Italian Triamterene
Portuguese Triantereno
Derived from the NIH UMLS (Unified Medical Language System)

Potassium Sparing Diuretics (C0304490)

Definition (MSH) A subclass of diuretics that limits the secretion of POTASSIUM into the URINE.
Definition (NCI) Any diuretic agent that produces diuresis without increasing potassium excretion. Potassium sparing diuretics are generally either aldosterone antagonists and thus prevent the aldosterone-mediated promotion of sodium and water retention, or are epithelial sodium channel blockers and prevent the exchange of potassium for sodium in the distal convoluted tubule. These agents cause diuresis without increasing potassium secretion and thus do not cause hypokalemia.
Concepts Pharmacologic Substance (T121)
MSH D062865
SnomedCT 371337002, 372753003, 47755009
English Potassium-Sparing Diuretic, K-sparing diuretics, potassium-sparing diuretics (medication), potassium-sparing diuretics, diuretics potassium sparing, potassium-sparing diuretic, potassium sparing diuretic, Diuretics, Potassium Sparing, POTASSIUM-SPARING DIURETICS, POTASSIUM-SPARING AGENTS, Potassium-sparing diuretic product (product), Potassium Sparing Diuretics, Potassium-sparing diuretic (substance), Potassium-sparing diuretic, Potassium sparing diuretic, Potassium-sparing diuretic (product), Potassium-sparring diuretic product, Potassium-sparing diuretic, NOS, Potassium-sparing Diuretics
Czech diuretika šetřící draslík, draslík šetřící diuretika, kalium šetřící diuretika
French Diurétiques épargneurs de potassium, Diurétiques d'épargne de potassium, Diurétiques d'épargne potassique, Diurétiques hyperkaliémiants, Diurétiques épargnant le potassium
German Diuretika, kaliumsparende, Kaliumsparende Diuretika
Italian Diuretici a risparmio di potassio
Spanish Diuréticos Conservadores de Potasio, producto con diurético ahorrador de potasio, producto con diurético ahorrador de potasio (producto), diurético ahorrador de potasio (sustancia), diurético ahorrador de potasio, producto (producto), diurético ahorrador de potasio, producto, diurético ahorrador de potasio, diurético ahorrador de potasio (producto)
Polish Diuretyki oszczędzające potas, Leki moczopędne oszczędzające potas
Croatian Not Translated[Diuretics, Potassium Sparing]
Norwegian Not Translated[Diuretics, Potassium Sparing]
Portuguese Diurético Poupador de Potássio
Derived from the NIH UMLS (Unified Medical Language System)

Dyrenium (C0700653)

Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D014223
English Dyrenium, Wellspring Brand of Triamterene
Derived from the NIH UMLS (Unified Medical Language System)

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