스피로노락톤

알도스테론 길항제 / 칼륨 보존 이뇨제

스피로노락톤은 합성 **알도스테론 길항제**이자 칼륨 보존 이뇨제입니다. 수의학에서는 주로 울혈성 심부전(CHF), 복수, 전신 고혈압 및 원발성 알도스테론증(특히 고양이)의 보조 치료제로 사용됩니다. **임상 요점 및 약리학적 배경:** * **알도스테론 회피(Aldosterone Escape):** 푸로세미드와 같은 루프 이뇨제에 비해 직접적인 이뇨 효과는 약하지만, 레닌-안지오텐신-알도스테론계(RAAS)를 차단하는 데 중요한 역할을 합니다. ACE 억제제를 복용 중인 환자라도 결국 알도스테론 수치가 다시 반등할 수 있는데(알도스테론 회피 현상), 스피로노락톤은 이를 완화합니다. * **심근 보호:** 인의학에서는 심근의 섬유화를 방지하고 해로운 심장 리모델링을 예방하는 효과로 높이 평가받고 있습니다. 수의학(예: 점액종성 승모판 질환이 있는 개)에서 이 이점의 정도에 대해서는 논란이 있지만, 표준 다제 병용 CHF 프로토콜에 점점 더 많이 포함되고 있습니다. * **생체이용률:** 음식과 함께 투여할 때 흡수율이 크게 향상됩니다.

작용 기전: Spironolactone acts as a competitive antagonist at the **mineralocorticoid receptor**. * **Mechanism:** It competitively inhibits **aldosterone** binding in the distal renal tubules and collecting ducts. * **Pathway:** Blockade of the receptor → prevents the synthesis of aldosterone-induced proteins (such as Na+/K+ ATPase and epithelial sodium channels) → **decreases sodium and chloride reabsorption** while **decreasing potassium, ammonium, and phosphate excretion**. * **Result:** Mild diuresis with potassium retention. It does not affect carbonic anhydrase or proximal renal transport mechanisms.

동물 종별 용량

Cats

As a diuretic in CHF (when furosemide and ACE inhibitors alone do not control fluid accumulation) · 1-2 mg/kg PO q12h · PO · q12h · Refractory CHF
As a diuretic in CHF (when serum potassium is low) · 1 mg/kg q12h PO · PO · q12h
For adjunctive treatment of hypertension · 1-2 mg/kg PO q12h · PO · q12h
For adjunctive treatment of hypertension (Step 3 drug) · 1-2 mg/kg twice daily · PO · q12h · When systolic BP >160 mmHg, diastolic >120 mmHg after amlodipine and ACE inhibitor.
For adjunctive treatment of primary hyperaldosteronism · 1-2 mg/kg PO twice daily · PO · q12h · If potassium supplementation alone does not control clinical signs.
Congestive heart failure, ascites, hyperaldosteronism · 2-4 mg/kg · PO · q24h · Continuous · Severe ulcerative facial dermatitis has been reported in Maine Coon cats.

Dogs

As a diuretic in CHF (when furosemide and ACE inhibitors alone do not control fluid accumulation) · 1-2 mg/kg PO q12h · PO · q12h · Refractory CHF
As a diuretic in CHF (with other diuretics when hypokalemia is an issue) · 2-4 mg/kg PO once daily · PO · q24h
As a diuretic in CHF (to allow further reduction of furosemide dose) · 0.5 mg/kg PO once daily to 2 mg/kg twice daily · PO · q24h to q12h · 0.5 mg/kg once daily for aldosterone blockage (weak diuretic effect); 2 mg/kg twice daily for stronger diuretic effect.

투여 경로

금기

Hyperkalemia
Addison's disease (hypoadrenocorticism)
Anuria
Acute renal failure
Significant renal impairment
Hypoadrenocorticism
Hyperkalaemia
Hyponatraemia
Concurrent use with NSAIDs in animals with renal insufficiency
Pregnancy
Lactation
Animals intended for breeding

이상반응

Facial dermatitis (notably reported in Maine Coon cats)
Hyperkalemia
Hyponatremia
Dehydration
Increased BUN and mild acidosis (in patients with renal impairment)
Gastrointestinal distress (vomiting, anorexia)
CNS effects (lethargy, ataxia)
Endocrine changes (anti-androgenic effects, e.g., gynecomastia in humans, feminization of male fetuses)
Hyponatraemia
Hyperkalaemia
Reversible prostatic atrophy (in entire male dogs)
Severe ulcerative facial dermatitis (in Maine Coon cats)
Hepatotoxicity (reported in humans)

약물 상호작용

Digoxin · Spironolactone may increase the half-life of digoxin; enhanced monitoring of digoxin serum levels is warranted. May also cause falsely elevated digoxin values if using a radioimmune assay (RIA). · moderate
Mitotane · Spironolactone may mute the effects of mitotane if given concurrently; monitor carefully.
Neuromuscular blockers, non-depolarizing · Possible increase in neuromuscular blockade effects.
Potassium-sparing diuretics (e.g., triamterene) · Increased risk of hyperkalemia.
Potassium supplements · Increased risk of hyperkalemia. · major
Salicylates (e.g., Aspirin) · Spironolactone's diuretic effects may be decreased if administered concomitantly.
Thiazide diuretics · Potentiates diuretic effects · moderate
Loop diuretics · Potentiates diuretic effects · moderate
ACE inhibitors · Increased risk of hyperkalaemia (though generally safe to use concurrently in practice; monitor potassium) · moderate
NSAIDs · Increased risk of hyperkalaemia and nephrotoxicity · major
Ciclosporin · Increased risk of hyperkalaemia · moderate

모니터링

Serum electrolytes (especially potassium and sodium)
BUN and creatinine
Hydration status
Blood pressure (if indicated)
Clinical signs of edema/ascites
Patient weight
Serum potassium
Serum sodium
Renal function (BUN, Creatinine)
Digoxin levels (if used concurrently)

과용량

Information on acute overdosage of spironolactone in veterinary patients is limited. * **Management:** Should an acute overdose occur, follow general guidelines for diuretic overdose (e.g., furosemide or chlorothiazide). * **Treatment:** Empty the stomach if ingestion was recent. Provide supportive care, monitor hydration status, and closely evaluate serum electrolytes (especially potassium and sodium). * Contact an animal poison control center for further guidance.

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