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Triamterene

ATC code C03DB02

Also known as: Triamteren

Key facts
Active substance
Triamterene
Drug class
Potassium-sparing diuretic
ATC code
C03DB02
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-10-29

Boxed warning

Abnormal elevation of serum potassium levels (greater than or equal to 5.5 mEq/liter) can occur with all potassium-sparing agents, including triamterene capsules. Hyperkalemia is more likely to occur in patients with renal impairment and diabetes (even without evidence of renal impairment), and in the elderly or severely ill. Since uncorrected hyperkalemia may be fatal, serum potassium levels must be monitored at frequent intervals especially in patients receiving triamterene capsules, when dosages are changed or with any illness that may influence renal function.

Key facts

Triamterene is a potassium-sparing diuretic. Per the US prescribing information, it is used to treat edema of various causes, alone or with other diuretics.

What it is used for

  • Edema associated with congestive heart failure, cirrhosis of the liver and the nephrotic syndrome
  • Steroid-induced and idiopathic edema and edema due to secondary hyperaldosteronism
  • Alone or with other diuretics, for added diuresis or for its potassium-sparing effect

Dosing

  • Titrate the dose to the individual patient
  • Used alone: usual starting dose 100 mg twice daily after meals
  • With another diuretic or antihypertensive, lower the initial daily dose of each agent
  • Total daily dose should not exceed 300 mg
  • When added to or switched from other diuretics, discontinue all potassium supplements; withdraw triamterene gradually

Contraindications

  • Anuria; severe or progressive kidney disease (possible exception: nephrosis); severe hepatic disease
  • Pre-existing elevated serum potassium or hyperkalemia during treatment
  • Concomitant potassium supplements, potassium salts or potassium-containing salt substitutes
  • Concomitant other potassium-sparing agents (e.g. spironolactone, amiloride)
  • Hypersensitivity to the drug or any component

Important warnings

  • Boxed warning: hyperkalemia (≥5.5 mEq/liter), possibly fatal if uncorrected; more likely with renal impairment, diabetes, in the elderly or severely ill; monitor serum potassium frequently
  • Obtain an ECG if hyperkalemia is present or suspected
  • Periodic BUN and potassium checks, especially in renal insufficiency, elderly and diabetic patients
  • Isolated hypersensitivity reactions; watch for blood dyscrasias and liver damage

Side effects

  • All adverse effects occur rarely (1 in 1000 or less)
  • Anaphylaxis, rash, photosensitivity; hyperkalemia or hypokalemia
  • Azotemia, elevated BUN and creatinine, renal stones, acute renal failure
  • Jaundice or liver enzyme abnormalities, nausea, vomiting, diarrhea; thrombocytopenia, megaloblastic anemia; weakness, fatigue, dizziness, headache, dry mouth

Interactions

  • Potassium-sparing agents, potassium supplements, ACE inhibitors: increased risk of hyperkalemia; two deaths reported with spironolactone
  • Lithium: risk of lithium toxicity; monitor levels closely
  • Indomethacin and other NSAIDs: acute renal failure reported; use caution
  • Antihypertensives, other diuretics, anesthetics, skeletal muscle relaxants: effects may be potentiated

Pregnancy and breastfeeding

  • Crosses the placenta; use only if clearly needed after weighing benefits and risks; routine diuretic use in healthy pregnant women is inappropriate
  • If use is essential, the patient should stop nursing

Summary of the official product information, written with AI on 2026-10-29. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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For patients

Patient information (US)

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

USA

  • DyreniumAdvanz Pharma (US) Corp. · 1 register entry

Source: U.S. FDA – Drug labels (openFDA/DailyMed), as of 2026-10-29

Brand names in 1 more European countries
Netherlands
Triamtereen Costero, Trlamtereen Accord

EMA – Article 57 product data (EU/EEA), 2026-10-29

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

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Medelix answers clinical questions from guidelines, studies and product information – every claim with its source.

Sources

  1. U.S. Food and Drug Administration. triamterene (Prasco Laboratories) – Prescribing Information, 2023-07-03. DailyMed (NLM), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=a09c2212-1dd5-4fbe-ad09-2a57aeabcaea
  2. U.S. FDA – Drug labels (openFDA/DailyMed), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/
  3. Wikidata (CC0): ATC C03DB.

Editorial: Medelix editorial team · last updated 2026-10-29 · How these pages are made · Report an error

Source: U.S. Food and Drug Administration (FDA), prescribing information, via DailyMed (NLM); public domain. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.