Page 148 - 2026 SMOG

METOPROLOL (LOPRESSOR)
Class/Mechanism of Action
• Beta Selective Beta-Blocker; Antihypertensive; Antianginal Agent
1
Selective inhibitor of Beta -adrenergic receptors; competitively blocks beta -receptors, with little
1
1
or no effect on Beta -receptors at oral doses <100mg (in adults); does not exhibit any membrane-
2
stabilizing or intrinsic sympathomimetic activity.
˚ Onset of action—IV: 5min; Duration—IV: 3–5 hours
Indications
• Labeled Indications
˚ Angina, hypertension, myocardial infarction
• Off-Label Indications
˚ Atrial fibrillation/flutter; hypertrophic cardiomyopathy; Marfan syndrome with aortic aneurysm;
migraine prophylaxis; supraventricular tachycardia (AVNRT, AVRT, focal atrial tachycardia);
thyrotoxicosis; ventricular arrhythmias
Contraindications
• Hypersensitivity to metoprolol, any component of the formulation, or other beta-blockers; second- or
third-degree heart block
• Severe sinus bradycardia (heart rate <45 beats/minute); significant first-degree heart block (P-R)
interval ≥0.24 seconds); systolic blood pressure <100mmHg; moderate to severe cardiac failure
Adverse Reactions/Precautions
• Cardiovascular: Hypotension, bradycardia, first-degree atrioventricular block, arterial insufficiency,
cardiac failure, CVA, cold extremities, palpitations, peripheral edema, claudication
• Central nervous system: Dizziness, fatigue, depression, vertigo, confusion, disturbed sleep,
hallucinations, headache, insomnia, nightmares, temporary amnesia, tinnitus
Dose/Administration
PEDIATRIC
ADULT
(Always reference Broselow Tape)
Atrial Fibrillation/Atrial Flutter Note: Guidelines do not recommend beta-blockers
• IV as initial therapy in pediatric patients; betablockers
˚ 2.5–5mg over 2–5min; repeat q5min prn should be reserved for use in patients who have
contraindications to preferred agents or patients
(max TOTAL dose: 15mg)
Supraventricular Tachycardia/ with hypertension and chronic kidney disease,
Ventricular Arrhythmia proteinuria, or diabetes mellitus
Note: For hemodynamically stable patients,
if vagal maneuvers and/or adenosine are
unsuccessful
• IV
˚ 2.5–5mg over 2–5min; repeat q5min prn to
achieve a ventricular rate of 90–100 (max
TOTAL dose: 15mg)
Note: For sustained ventricular tachycardia, beta-
blockers are generally administered in addition
to an antiarrhythmic drug (e.g., Amiodarone)
for these indications. A beta-blocker is also used
to reduce shocks in patients who receive an
implantable cardioverter defibrillator for these
indications; propranolol may be the preferred beta-
blocker in these situations.
140 • MEDICATIONS