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トリアムテレン

Triamterene

2,4,7-triamino-6-phenylpteridine

カリウム保持性利尿薬PO犬

別名: Dyrenium · Dytac · Dyazide · Maxzide · Triteren · NSC-77625 · KF-8542 · FI-6143 · triamteren · trimaterenum · triamtereen

VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス

1-2 mg/kg PO q12hPO· q12h
— 🐕

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

動物種別用量

🌎 NA — North America🌍 EU — Europe

犬

適応用量経路頻度期間地域
Adjunctive treatment of recurrent heart failure associated with chronic mitral valve insufficiency1-2 mg/kg PO q12hPOq12h—🌎 NA
As a diuretic for adjunctive treatment of CHF2-(4) mg/kg/day POPOq24h—🌎 NA
  • Adjunctive treatment of recurrent heart failure associated with chronic mitral valve insufficiency: Documentation of use is limited; spironolactone is drug of choice.

用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。

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概要

トリアムテレンは​カリウム保持性利尿薬​であり、犬の​うっ血性心不全（CHF）​の補助治療においてスピロノラクトンの代替薬として検討されることがあります。

  • ​臨床的有用性​: 獣医療における使用経験および薬物動態データは限られています。小動物には、通常スピロノラクトンが第一選択となります。
  • ​主な利点​: ループ利尿薬（フロセミドなど）やチアジド系利尿薬でよく見られる過剰なカリウム喪失を防ぎつつ、浮腫や体液貯留を管理するのに役立ちます。

作用機序

Triamterene exerts a direct effect on the late distal convoluted tubule and collecting duct of the kidneys.

  • Mechanism: It directly blocks ​epithelial sodium channels (ENaC)​ on the lumenal side of the kidney tubule → inhibits the reabsorption of sodium (Na+) → decreases the electrical gradient across the tubular membrane → reduces the driving force for the secretion and excretion of potassium (K+) and hydrogen (H+) ions.
  • Aldosterone Independence: Unlike spironolactone, triamterene does not competitively inhibit aldosterone. Its action is independent of endogenous aldosterone levels.
  • Net Effect: Increases urinary excretion of sodium, calcium, magnesium, and bicarbonate while retaining potassium and chloride. It has little effect on blood pressure when used alone but can slightly reduce Glomerular Filtration Rate (GFR).

安全性・警告

禁忌

  • Anuria
  • Severe or progressive renal disease
  • Severe hepatic disease
  • Hypersensitivity to triamterene
  • Preexisting hyperkalemia or history of triamterene-induced hyperkalemia
  • Concurrent therapy with another potassium-sparing agent (e.g., spironolactone, amiloride)
  • Concurrent potassium supplementation

有害事象

  • Hyperkalemia (most significant risk)
  • Gastrointestinal upset
  • Hyponatremia
  • Headache or dizziness (reported in humans)
  • Increased sensitivity to sunlight
  • Hypersensitivity reactions (rare)
  • Nephrolithiasis (rare)
  • Blood dyscrasias such as agranulocytosis, thrombocytopenia, or megaloblastosis (rare)

注意事項

Warning: Hyperkalemia is a definite possibility. Monitoring of electrolytes and renal function is strictly necessary.

  • Renal Function: May slightly reduce GFR (reversible upon discontinuation). Use with caution in patients with compromised renal blood flow.
  • Pregnancy: Crosses the placental barrier. Animal studies (rats) at 6-20X human dose showed no adverse fetal effects, but adequate studies are lacking. Weigh potential benefits against risks.
  • Lactation: Distributed into milk. Safety during nursing cannot be assured.

医薬品相互作用

ACE Inhibitors (e.g., enalapril, benazepril)

Increased risks for hyperkalemia.

Antidiabetic Agents (insulin, oral hypoglycemics)

Triamterene may increase blood glucose levels.

Antihypertensive Agents

Possible potentiation of hypotensive effects.

Diuretics, Potassium-Sparing (spironolactone, amiloride)

Increased risk of hyperkalemia; concurrent use is contraindicated.

Lithium

Triamterene may reduce lithium clearance, increasing the risk of lithium toxicity.

NSAIDs (especially indomethacin)

May increase the risks of nephrotoxicity when used concurrently.

Potassium Supplements or High Potassium Foods

Increased risk for hyperkalemia.

Quinidine

Laboratory interaction: Triamterene may interfere with the fluorescent assay of quinidine.

監視

  • Serum electrolytes (especially potassium)
  • BUN and creatinine
  • Hydration status
  • Blood pressure, if indicated
  • Signs of edema
  • Patient weight, if indicated

薬物動態

吸収

In humans, rapidly absorbed after oral administration with an oral bioavailability of about 85%. Onset of diuresis occurs in 2-4 hours and diminishes after about 8 hours.

分布

Crosses the placental barrier and is distributed into milk.

代謝

Metabolized in the liver to 6-p-hydroxytriamterine and its sulfate conjugate.

消失

Metabolites are eliminated in the bile/feces and urine.

過剰投与

The oral LD50 for triamterene in mice is 380 mg/kg.

  • Clinical Signs: Fluid and electrolyte imbalance (especially hyperkalemia) is the most likely risk. Gastrointestinal effects or hypotension are also possible.
  • Management: Consider gut emptying protocols for very large or unknown quantity ingestions. Acute overdoses should generally be managed by observation, with rigorous fluid, electrolyte (especially serum potassium), and acid-base monitoring. Initiate supportive treatment as required.

製品

製剤

  • Capsules
  • Tablets (typically in combination with hydrochlorothiazide)

動物用医薬品

  • None

ヒト用医薬品

  • Triamterene Capsules: 50 mg & 100 mg (Dyrenium)
  • Triamterene 37.5 mg / Hydrochlorothiazide 25 mg Tablets and Capsules (Dyazide, Maxzide-25MG, generic)
  • Triamterene 50 mg / Hydrochlorothiazide 25 mg Capsules (generic)
  • Triamterene 75 mg / Hydrochlorothiazide 50 mg Tablets (Maxzide, generic)

規制ステータス

規制データなし: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

保管・安定性

Triamterene capsules should be stored between 15-30°C (59-86°F) in tight, light-resistant containers.

飼主向け情報

  • ​投与方法​: 胃の不調を防ぐため、食事と一緒に与えてください。
  • ​尿の色​: 服薬中、ペットの尿が​青みがかった色​になることがありますが、これは正常で無害な反応です。
  • ​監視​: この薬は犬や猫ではあまり使用されないため、ペットの様子を注意深く観察し、異常な反応（激しい無気力、脱力感、嘔吐など）があれば、すぐに獣医師に報告してください。
  • ​食事の制限​: 獣医師の特別な指示がない限り、カリウムのサプリメントやカリウムを多く含む食品・おやつを与えないでください。

VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。