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**λ©ν νλ‘€λ‘€(Metoprolol)**μ μ¬μ₯ μ νμ±(**λ² ν1-νΉμ΄μ **) μλλ λ λ¦° μμ©μ²΄ μ°¨λ¨μ λ‘, μμνμμ λ€μν μ¬νκ΄κ³ μ§ν κ΄λ¦¬μ λ리 μ¬μ©λ©λλ€. μ£Όμ μμ μ μ© λΆμΌλ λ€μκ³Ό κ°μ΅λλ€: * **μμ¬μ€μ± λΉλ§₯** λ° μ¬μ€ μ‘°κΈ° μμΆ(PVCs/VPCs) κ΄λ¦¬. * **μ μ μ± κ³ νμ** μΉλ£. * κ³ μμ΄μ **λΉλμ± μ¬κ·Όλ³μ¦(HCM)** μΉλ£ (λμ μ’μ¬μ€ μ μΆλ‘ νμλ₯Ό μ€μ΄κ³ μ΄μκΈ° μΆ©λ§ μκ°μ κ°μ νλ λ° λμμ μ€). μλμ μΈ λ² ν1-μ νμ± λλ¬Έμ **κΈ°κ΄μ§ μμΆμ± μ§ν**(μ: κ³ μμ΄ μ²μ)μ λλ°ν νμμμ λΉμ νμ± λ² ν μ°¨λ¨μ (μ: νλ‘νλΌλλ‘€)λ³΄λ€ μΌλ°μ μΌλ‘ λ μμ ν κ²μΌλ‘ κ°μ£Όλμ§λ§, κ³ μ©λμμλ μ νμ±μ΄ μμ€λ μ μμΌλ―λ‘ μ¬μ ν μ£Όμκ° νμν©λλ€.
μμ© κΈ°μ : Metoprolol competitively blocks **beta1-adrenergic receptors** located primarily in the myocardium. **Mechanism Pathway:** Blockade of beta1-receptors β decreased activation of adenylyl cyclase β reduced intracellular cAMP β decreased intracellular calcium influx. This results in: * **Negative chronotropy**: Decreased sinus heart rate. * **Negative dromotropy**: Slowed atrioventricular (AV) conduction. * **Negative inotropy**: Decreased myocardial contractility and cardiac output. * Decreased myocardial oxygen demand and reduced blood pressure. *Clinical Pearl*: Metoprolol lacks intrinsic sympathomimetic activity (ISA) and membrane-stabilizing activity. At higher dosages, its cardioselectivity diminishes, leading to **beta2-receptor blockade** in bronchial smooth muscle β potential bronchoconstriction.
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- As an oral beta blocker Β· 2-15 mg (total dose) PO q8h Β· PO Β· q8h
- For rate control in chronic atrial fibrillation Β· 0.25-1 mg/kg PO q1224h. Β· PO Β· q1224h Β· Note: 'q1224h' is transcribed exactly as it appears in the source text, likely a typo for q12-24h.
- For CHF (early/mild or well-controlled) Β· 0.2 mg/kg PO twice daily, with slow titration upwards every 2-3 weeks up to 0.4-6.6 mg/kg PO three times a day. Β· PO Β· BID to TID Β· Many dogs will not tolerate this upward titration.
- To decrease the incidence of atrial fibrillation and flutter in dogs undergoing valve surgery Β· 0.4-1 mg/kg PO q24h Β· PO Β· q24h Β· Using sustained release metoprolol (ToprolXR) administered before and as soon as feasible after surgery.
μ©λμ λ©΄ν μμ μ λ¬Έκ°λ₯Ό μν μμ μ°Έκ³ μλ£μ λλ€. νμ μ΅μ λΌλ²¨κ³Ό κ°λ³ νμμ λν΄ νμΈνμμμ€.
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- Overt or unstable heart failure
- Hypersensitivity to beta-blockers
- Greater than first-degree heart block
- Sinus bradycardia
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- Bradycardia
- Lethargy and depression
- Impaired AV conduction
- Congestive heart failure (CHF) or worsening of heart failure
- Hypotension
- Hypoglycemia
- Bronchoconstriction (at high doses)
- Syncope
- Diarrhea
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- General Anesthetics Β· Increased risk for heart failure and hypotension due to additive myocardial depressant effects.
- Calcium-Channel Blockers (e.g., diltiazem, verapamil, amlodipine) Β· Concurrent use should be done with caution; additive negative inotropic and chronotropic effects, particularly in patients with preexisting cardiomyopathy or CHF.
- Digoxin Β· May increase negative effects on SA or AV node conduction.
- Diuretics (thiazides, furosemide) Β· May increase the hypotensive effect of metoprolol.
- Hydralazine Β· May increase the risks for pulmonary hypertension in uremic patients.
- Quinidine Β· May increase metoprolol plasma concentrations.
- Reserpine Β· Potential for additive effects including hypotension and bradycardia.
- SSRI Antidepressants (e.g., fluoxetine, sertraline, paroxetine) Β· May increase metoprolol plasma concentrations.
- Sympathomimetics (e.g., metaproterenol, terbutaline, epinephrine, phenylpropanolamine) Β· May have their actions blocked by metoprolol, and they may in turn reduce the efficacy of the beta-blocker.
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- Cardiac function
- Pulse rate
- ECG (if necessary)
- Blood pressure (if indicated)
- Signs of toxicity (bradycardia, hypotension, lethargy)
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Overdosage primarily results in extensions of the drug's pharmacologic effects: **hypotension, bradycardia, bronchospasm, cardiac failure, and potentially hypoglycemia**. **Treatment:** * **Decontamination**: If recent oral ingestion, consider emptying the gut and administering activated charcoal. *Caution*: Inducing emesis can be risky as coma and seizures may develop rapidly. * **Monitoring**: Continuous ECG, blood pressure, blood glucose, and potassium. * **Cardiovascular Support**: Treat symptomatically. Use IV fluids and pressor agents for hypotension. * **Bradycardia**: Treat with atropine. If atropine fails, isoproterenol may be given cautiously. A transvenous pacemaker may be necessary. * **Cardiac Failure**: May be treated with digitalis glycosides, diuretics, and oxygen. * **Antidote**: Glucagon (5-10 mg IV - human dose) may increase heart rate and blood pressure and reduce the cardiodepressant effects of metoprolol.
VetSheet μ½λ¬Ό λ νΌλ°μ€λ λ©΄ν μμ μ λ¬Έκ°λ₯Ό μν μμ μμ¬κ²°μ 보쑰 λꡬμ΄λ©°, μ λ¬Έμ νλ¨μ΄λ μ μ‘°μ¬μ μ΅μ λΌλ²¨μ λμ νμ§ μμ΅λλ€.