【缺藥訊息】 公告日期：2024/02/23 缺藥品項：【E2】Betaloc Zok 片裝 25mg 缺藥原因：因藥委會刪除，且廠商即將停產 配套措施：剩餘量保留慢性處方箋回院調劑 #特殊劑型：不建議磨粉、管灌藥品

高血壓 (Beta-blocker) 治療心衰竭 治療心絞痛 Angina pectoris.
Congestive heart failure.
Hypertension.

Metoprolol succinate is a beta-adrenergic blocker with selective activity on beta-1 adrenoreceptors located mainly in cardiac muscles. At higher doses, metoprolol also inhibits beta-2 adrenoreceptors of bronchial and vascular smooth muscles. Possible mechanisms of antihypertensive effects of metoprolol include: competitive antagonism of catecholamines at peripheral and cardiac adrenergic receptors (resulting in decreased cardiac output), a central effect leading to reduced sympathetic outflow, and suppression of renin activity. The exact mechanism for the beneficial effects of metoprolol in heart failure is unknown

Absorption:
Bioavailability, oral, extended-release tablet: 77% relative to immediate-release oral formulation
Distribution:
Vd: 5.6 L/kg
Metabolism:
Liver: main route via CYP2D6
Excretion:
Renal, oral: less than 5% unchanged
Elimination Half Life:
3 to 7 hours

Cardiogenic shock
Decompensated cardiac failure
Hypersensitivity to metoprolol succinate or any component of the product
Second- or third-degree heart block
Severe bradycardia
Sick sinus syndrome (without a functional permanent pacemaker)

C (FDA) (AUS)

Maternal medication usually compatible with breastfeeding.(AAP)
Infant risk is minimal.(MDX)

Common:
Cardiovascular: Bradyarrhythmia (3%), Cold extremities (1%), Heart failure (1%), Hypotension (1%)
Dermatologic: Pruritus (5% ), Rash (5% )
Gastrointestinal: Constipation (1%), Diarrhea (5%), Indigestion (1%), Nausea (1%)
Neurologic: Dizziness (10%), Fatigue (10%), Headache
Psychiatric: Depression (5%)
Respiratory: Dyspnea (3%), Wheezing (1%)
Serious:
Respiratory: Bronchospasm (1%)

Acute myocardial infarction:
Initial dose: Metoprolol tartrate orally 25 to 50 mg every 6 to 12 hours, then transition in 2 to 3 days to metoprolol succinate and titrate to 200 mg once daily as tolerated.
Angina pectoris:
Initial, 100 mg orally once daily; increase dose gradually at weekly intervals based on clinical response and tolerability; dosages above 400 mg daily have not been studied .
Discontinuing therapy, gradually reduce dosage over 1 to 2 weeks .
Switching from immediate-release metoprolol to metoprolol succinate, use the same total daily dose of metoprolol succinate .
Congestive heart failure:
Prior to initiation, stabilize dosage of other heart failure medication(s)
(NYHA class II) Initial, 25 mg orally once daily for 2 weeks
(NYHA class III) Initial, 12.5 mg orally once daily for 2 weeks
Dosage titration, double every 2 weeks to highest tolerated dose or up to 200 mg daily. Reduce dose if symptomatic bradycardia occurs. Consider reducing dose, temporary discontinuation, or increasing diuretic doses if transient worsening of heart failure occurs; do not increase dosage until symptoms of worsening heart failure have stabilized.
Hypertension:
Initial, 25 to 100 mg orally once daily
Dosage titration, increase dosage at weekly or longer intervals to achieve optimum antihypertensive effect; dosages above 400 mg daily have not been studied
When switching from immediate-release metoprolol to metoprolol succinate, use the same total daily dose of metoprolol succinate .

(6 years or older) Initial, 1 mg/kg orally once daily; MAX 50 mg once daily; adjust dosage based on clinical response.
Dosages above 2 mg/kg or 200 mg once daily have not been studied

Adjustment not necessary?.

Initiate therapy at lower dose based on indication and increase dosage gradually.