Triamterene
DYRENIUM
Pronunciation: trye-AM-ter-een
“Die renally by Trampoline”
Bananas in bunches → ↑ serum potassium
Frightened kidneys → potential for nephrotoxicity
What it isEpithelial sodium-channel blocker in the collecting duct; edema, usually treated alongside a thiazide.
Why this oneDirect ENaC blockade avoids spironolactone's hormonal effects, but its modest diuresis usually makes it a thiazide partner.
What limits itHyperkalemia is the central hazard, especially with an ACE inhibitor or ARB; it can also form kidney stones.
FDA-approved for
- edema (K-sparing) (~1964)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Edema (CHF, hepatic cirrhosis, nephrotic syndrome; steroid-induced, idiopathic, secondary hyperaldosteronism) | Adults | 100 mg BID after meals (when used alone) | Titrate to individual response | 300 mg/day |
Renal Contraindicated in anuria and in severe or progressive kidney disease or dysfunction (possible exception: nephrosis)
Hepatic Contraindicated in severe hepatic disease; observe cirrhotics for exacerbation of underlying liver disease
Instructions
- Take after meals to reduce stomach upset; if QD, prefer morning dosing
- Discontinue all potassium supplementation when adding to or switching from other diuretics
- When combined with another diuretic or antihypertensive, lower the initial daily dose of each agent, then adjust
- Monitor serum potassium frequently (especially renal impairment, diabetes, elderly, severely ill); periodic BUN, creatinine and blood counts
Available strengths
- cap 50, 100 mg
Contraindications
- Anuria
- Severe or progressive kidney disease or dysfunction (possible exception: nephrosis)
- Severe hepatic disease
- Pre-existing elevated serum potassium, or hyperkalemia developing on the drug
- Dietary potassium supplements, potassium salts, or potassium-containing salt substitutes
- Other potassium-sparing agents (spironolactone, amiloride, other triamterene-containing formulations) — deaths reported with concomitant spironolactone
Cautions
- Hyperkalemia (K+ >=5.5 mEq/L) can occur and may be fatal if uncorrected — monitor potassium frequently; obtain ECG if hyperkalemia suspected
- Highest hyperkalemia risk: renal impairment, diabetes (even without renal impairment), elderly, severely ill
- Idiosyncratic blood dyscrasias and liver damage — observe regularly
- Electrolyte imbalance in CHF, renal disease, cirrhosis; possible metabolic acidosis; mild reversible nitrogen retention
- Weak folic acid antagonist — megaloblastosis risk with depleted folate stores (e.g., cirrhotics); periodic blood studies
- Elevates uric acid (gout predisposition); caution with history of renal stones (triamterene found in stones)
Adverse reactions
- Hyperkalemia
- Hypokalemia
- Azotemia / elevated BUN and creatinine
- Renal stones
- Acute interstitial nephritis (rare)
- Acute renal failure (one irreversible case)
- Jaundice / liver enzyme abnormalities
- Nausea/vomiting
- Diarrhea
- Thrombocytopenia
- Megaloblastic anemia
- Weakness/fatigue
- Dizziness
- Headache
- Dry mouth
- Anaphylaxis
- Rash
- Photosensitivity
Pregnancy No fetal harm in rat studies up to 20x MRHD; crosses placenta into cord blood; use only if clearly needed — routine diuretic use in healthy pregnant women is inappropriate
Lactation Undefined
Cost
Generic entry2019
⚠ BOXED WARNING
- Abnormal elevation of serum potassium
Principal riskHyperkalemia
Classes and tags
Clinical profile
Legacy pregnancy categoryC
Defining liabilityHyperkalemia and kidney dysfunction, especially with RAAS blockers or impaired renal function.
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