메타졸라미드

탄산탈수효소 억제제

**메타졸라미드(Methazolamide)**는 수의학에서 주로 **개방각 녹내장**의 내과적 치료에 사용되는 경구용 **탄산탈수효소 억제제(CAI)**입니다. 과거에는 안압(IOP)을 낮추기 위한 주요 약물이었으나, 현재 전신성 CAI는 대부분 국소 점안제(예: 도르졸라미드, 브린졸라미드)로 대체되었습니다. 국소 제제는 전신 부작용 발생률이 훨씬 낮으면서도 유사한 안압 감소 효과를 제공합니다. 주요 임상 포인트: * **전신적 영향:** 경구로 투여되기 때문에 메타졸라미드는 전신의 탄산탈수효소를 억제하여 대사성 산증 및 전해질 불균형(특히 저칼륨혈증)을 유발할 수 있습니다. * **임상적 유용성:** 일반적으로 국소 치료에 반응하지 않는 난치성 녹내장 환자나 국소 투여가 불가능한 경우에 제한적으로 사용됩니다. * **종 특이적 민감성:** 고양이는 경구용 CAI의 부작용에 특히 민감하며 심각한 기면 및 식욕 부진을 보일 수 있습니다.

작용 기전: Methazolamide acts via noncompetitive, reversible inhibition of the enzyme **carbonic anhydrase (CA)**, specifically the **CA-II isoenzyme**. * **In the Eye (Ciliary Body):** Inhibition of CA → reduces the formation of hydrogen (H+) and bicarbonate (HCO3-) ions from carbon dioxide and water → decreases the availability of these ions for active transport into the posterior chamber → **decreased aqueous humor production** → **reduced intraocular pressure (IOP)**. * **In the Kidneys (Proximal Tubule):** Inhibition of CA → increased renal tubular secretion of sodium (Na+), potassium (K+), and bicarbonate (HCO3-) → **increased urine alkalinity and volume**, often resulting in a mild **hyperchloremic metabolic acidosis**. * **In the CNS:** Exhibits anticonvulsant activity independent of its diuretic effects, potentially due to localized CA inhibition in the brain or secondary to systemic metabolic acidosis.

동물 종별 용량

Cats

Medical treatment of glaucoma · 3-4 mg/kg PO twice a day. · PO · twice a day · Cats may not tolerate oral carbonic anhydrase inhibitors (CAIs) as well as dogs. Reported side effects include lethargy, inappetence, vomiting. Topical CAIs may be better tolerated.
Medical treatment of glaucoma · 1-2 mg/kg PO q8-12h · PO · q8-12h

Dogs

Medical treatment of glaucoma · 2.5-5 mg/kg PO q8-12h · PO · q8-12h
Medical treatment of glaucoma · 2-4 mg/kg PO two to three times a day · PO · two to three times a day
Medical treatment of glaucoma · 3-5 mg/kg divided q12h PO · PO · q12h
Medical treatment of glaucoma · 2-5 mg/kg PO two to three times a day · PO · two to three times a day
Medical treatment of glaucoma · 2.2-4.4 mg/kg PO two to three times a day. · PO · two to three times a day
Medical treatment of glaucoma · 2-10 mg/kg PO two to three times a day. · PO · two to three times a day

용량은 면허 수의 전문가를 위한 임상 참고 자료입니다. 항상 최신 라벨과 개별 환자에 대해 확인하십시오.

투여 경로

금기

Significant hepatic disease (may precipitate hepatic coma)
Renal or adrenocortical insufficiency
Hyponatremia or hypokalemia
Hyperchloremic acidosis or severe electrolyte imbalance
Severe pulmonary obstruction (inability to increase alveolar ventilation to compensate for metabolic acidosis)
Hypersensitivity to carbonic anhydrase inhibitors or sulfonamides
Chronic, noncongestive, angle-closure glaucoma (long-term use may mask the condition by lowering IOP while angle closure progresses)

이상반응

GI disturbances (vomiting, diarrhea, inappetence)
Metabolic acidosis (often manifesting as heavy panting in dogs)
CNS effects (sedation, depression, disorientation, excitement)
Hematologic effects (bone marrow depression, thrombocytopenia)
Renal effects (crystalluria, dysuria, renal colic, polyuria, polydipsia)
Hypokalemia
Hyperglycemia
Hyponatremia
Hyperuricemia
Hepatic insufficiency
Dermatologic effects (rash)
Hypersensitivity reactions
Weakness or cardiac arrhythmias (secondary to electrolyte imbalances)

약물 상호작용

Antidepressants, Tricyclic · Alkaline urine caused by methazolamide may decrease excretion of tricyclic antidepressants.
Aspirin (or other salicylates) · Increased risk of methazolamide accumulation and toxicity; increased risk for metabolic acidosis; methazolamide increases salicylate excretion.
Digoxin · Methazolamide may cause hypokalemia, leading to an increased risk for digoxin toxicity.
Insulin · Rarely, carbonic anhydrase inhibitors may interfere with the hypoglycemic effects of insulin.
Methenamine compounds · Methazolamide alkalinizes urine, which may negate the urinary antiseptic effects of methenamine.
Potassium-depleting drugs (corticosteroids, amphotericin B, corticotropin, diuretics) · Concomitant use may exacerbate potassium depletion and hypokalemia.
Phenobarbital · Increased urinary excretion due to alkaline urine, which may reduce phenobarbital serum levels.
Primidone · May result in decreased primidone concentrations.
Quinidine · Alkaline urine caused by methazolamide may decrease quinidine excretion.

모니터링

Intraocular pressure (IOP) / tonometry
Serum electrolytes (especially potassium and sodium)
Blood pH / acid-base status
Baseline CBC with differential, and periodic retests if using chronically
Clinical signs of adverse effects (lethargy, GI upset, heavy panting)

과용량

Information regarding acute overdosage of methazolamide in veterinary species is limited. **Clinical Signs:** Expected signs of toxicity include severe electrolyte imbalances (hypokalemia, hyponatremia), profound metabolic acidosis, CNS depression or disorientation, and dehydration secondary to diuresis. **Management:** * Monitor serum electrolytes, blood gases (for acidosis), volume status, and CNS status. * Treat symptomatically and supportively. * Administer intravenous fluids to correct dehydration and electrolyte deficits (especially potassium supplementation if indicated). * Correct severe metabolic acidosis with sodium bicarbonate if necessary, based on blood gas analysis.

VetSheet 약물 레퍼런스는 면허 수의 전문가를 위한 임상 의사결정 보조 도구이며, 전문적 판단이나 제조사의 최신 라벨을 대신하지 않습니다.