아세틸시스테인

해독제 / 점액용해제

아세틸시스테인(흔히 NAC로 불림)은 수의학에서 매우 다용도로 사용되는 치료제입니다. 특히 개와 고양이에서 **아세트아미노펜(타이레놀) 중독의 생명을 구하는 해독제**로 가장 잘 알려져 있으며, 심각한 간 괴사와 메트헤모글로빈혈증을 예방합니다. 해독 특성 외에도 아세틸시스테인은 강력한 **점액용해제**입니다. 호흡기로 투여될 때 끈적하고 점성이 높은 점액을 효과적으로 분해하여 호흡기 분비물의 배출을 돕습니다. **임상 적용:** * **독성학:** 아세트아미노펜, 자일리톨, 페놀 중독의 일차 치료제. * **호흡기계:** 만성 상부 호흡기 질환이나 점액 부담이 큰 상태를 치료하기 위해 네뷸라이저 또는 기관 내 주입으로 사용. * **안과:** 콜라게나아제를 억제하여 '각막 융해(melting)' 궤양의 진행을 막기 위해 국소적으로 적용. * **말 의학:** 기낭 내 연골양 물질을 용해하기 위해 국소적으로 사용되며, 신생 망아지의 난치성 태변 매복에 관장제로 사용. * **내과:** 고양이 지방간증의 보조 치료 및 반려견의 퇴행성 골수병증에 대한 경험적 치료제로 사용.

작용 기전: **Antidote Mechanism (Hepatoprotection):** Acetaminophen is metabolized in the liver to a highly reactive and toxic intermediate called **NAPQI** (N-acetyl-p-benzoquinone imine). Normally, NAPQI is safely conjugated by endogenous **glutathione**. In an overdose, glutathione is rapidly depleted, allowing NAPQI to cause severe oxidative stress and hepatocellular necrosis. Acetylcysteine acts as a **glutathione precursor** and provides an alternate sulfhydryl substrate to conjugate directly with NAPQI, thereby neutralizing the toxin and restoring cellular antioxidant defenses. **Mucolytic Mechanism:** The free **sulfhydryl group (-SH)** on the acetylcysteine molecule directly interacts with mucoproteins in respiratory secretions. It cleaves the **disulfide bonds** linking these proteins, which drastically reduces the viscosity of both purulent and non-purulent mucus. This effect is optimal in an alkaline environment (pH 7-9). It has no effect on living tissue or fibrin.

동물 종별 용량

Dogs

Acetaminophen toxicity · 140 mg/kg PO loading dose, followed by 70 mg/kg PO q6h · PO · q6h · For 7 treatments (up to 12-17 doses for massive ingestions) · Dilute to 5% in dextrose or sterile water. May also be given slow IV over 15-20 minutes. Wait 2-3 hours after activated charcoal if giving PO.
Acetaminophen toxicity · 150 mg/kg PO or IV initially, then 50 mg/kg q4h · PO/IV · q4h · For 17 additional doses
Acetaminophen toxicity · 140 mg/kg PO loading dose, then 70 mg/kg PO every 6 hours · PO · q6h · For 7 treatments
Phenol toxicity · 140 mg/kg PO or IV initially, then 50 mg/kg q4h · PO/IV · q4h · For 3 days · May be partially effective to reduce hepatic and renal injury.
Hepatotoxicity secondary to xylitol poisoning · 140-280 mg/kg loading dose IV or PO; followed by 70 mg/kg four times daily · IV/PO · q6h · Used as part of a comprehensive protocol including vitamin K, plasma, SAMe, vitamin E, and silymarin.
Degenerative myelopathy (anecdotal) · 25 mg/kg PO q8h for 2 weeks, then q8h every other day · PO · q8h · Indefinitely (every other day after 2 weeks) · Dilute 20% solution to 5% with chicken broth. Used in conjunction with aminocaproic acid. Note: No treatment has been shown to be effective in published trials.
Mucolytic · nebulize 50 mg as a 2% (dilute with saline) solution over 30-60 min or instil directly into the trachea 1-2 ml of a 20% solution · Nebulization/Intratracheal · prn · As needed · Dilute with saline for nebulization.
Paracetamol poisoning · 140-280 mg/kg diluted to a 5% solution using 5% dextrose by slow i.v. infusion over 15-20 min, followed by further slow infusions of 70 mg/kg (similarly diluted) every 6 hours · IV · q6h · for at least 7 doses · Administer after inducing emesis if appropriate (within 2 hours of ingestion). IV preferred for serious intoxications. Can be given PO but must be diluted to improve palatability.

투여 경로

POIVInhalation (Nebulization)IntratrachealTopical ophthalmicEnemaIntra-guttural pouch instillation

금기

Hypersensitivity to the drug (specifically for pulmonary indications)

이상반응

Nausea and vomiting (especially with oral administration due to poor palatability)
Urticaria (rare)
Bronchospasm, chest tightness, and bronchial/tracheal irritation (when inhaled)
Blood pressure changes and allergic reactions (reported with IV boluses in humans)

약물 상호작용

Activated Charcoal · May adsorb orally administered acetylcysteine, potentially reducing its systemic absorption and efficacy. A 2-3 hour wait between charcoal and oral acetylcysteine is recommended, or acetylcysteine should be given intravenously. · moderate

모니터링

Hepatic enzymes (especially in dogs)
Acetaminophen levels (if available)
Hemogram, specifically monitoring methemoglobin values (especially critical in cats)
Serum electrolytes
Hydration status

과용량

Acetylcysteine is considered quite safe in overdose situations. The LD50 in dogs is reported to be 1 g/kg orally and 700 mg/kg intravenously. Massive overdoses may result in gastrointestinal distress (nausea, vomiting) or hypersensitivity reactions, but life-threatening toxicity from the drug itself is rare.

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