Potassium-sparing diuretic, collecting duct sodium channel blocker
ATC code: C03DB02 (Triamterene)
Brand names
Dyrenium, Dyazide (combo)
Blocks epithelial sodium channels (ENaC) in distal tubules and collecting ducts. Reduces sodium reabsorption and potassium/hydrogen secretion. Weak diuretic effect, usually given as a fixed-dose combination with a thiazide to prevent hypokalaemia. Renally excreted.
Second line
Triamterene combined with hydrochlorothiazide is used for edema in heart failure, cirrhosis or nephrotic syndrome when thiazide alone causes marked hypokalaemia. SEC and AEMPS recommend checking potassium and creatinine at 1 and 4 weeks after initiation, especially in the elderly.
2 pairs found. Sorted from critical to minor.
Mechanism
Both are potassium-sparing diuretics. Combined use produces dual potassium retention and severe hyperkalaemia with risk of fatal arrhythmia.
Symptoms
K+ above 6.5 mmol/L, muscle weakness, arrhythmia, ECG peaked T waves.
Management
Combination contraindicated. Choose one potassium-sparing diuretic.
Sources
Mechanism
Enalapril suppresses aldosterone – less potassium excreted. With triamterene additive hyperkalaemia, especially in CKD.
Symptoms
Hyperkalaemia within 2 weeks.
Management
Check potassium and creatinine at 1 and 4 weeks. Reduce triamterene if K+ above 5.0.
Sources
Opens the checker prefilled with this drug. Pick the second one from your regimen.
Limited data. Thiazides and K-sparing diuretics are avoided in pregnancy – risk of hypovolaemia and impaired placental flow.
Passes into milk in small amounts. Breastfeeding possible with infant electrolyte monitoring.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
Triamterene is evaluated for the following indications with varying evidence strength: Edema and fluid overload (evidence tier B). See the full indication matrix with dosing and citations above on this page.
Common side effects of Triamterene (≥ 1 in 100): Hyperkalaemia, Nausea, Headache, Dry mouth, Photosensitivity. See the Safety section for uncommon and serious reactions.
FDA category C. Limited data. Thiazides and K-sparing diuretics are avoided in pregnancy – risk of hypovolaemia and impaired placental flow.
Passes into milk in small amounts. Breastfeeding possible with infant electrolyte monitoring.
Triamterene is contraindicated in: Hyperkalaemia (K+ above 5.5 mmol/L); Severe renal impairment (eGFR below 30 mL/min); Combination with spironolactone, eplerenone, amiloride; Combination with potassium supplements; Addison disease. Full list in the Safety section.