Immediate-Acting, Non-Extended Release Beta Blockers

Metoprolol tartrate is the most appropriate immediate-acting, non-extended release beta blocker for clinical use. 1, 2

Immediate-Acting Beta Blockers Available

Immediate-acting beta blockers include:

Metoprolol tartrate: Available as immediate-release formulation with dosing of 25-200 mg twice daily, with a short duration of action (3-4 hours half-life) 1, 2
Propranolol: Available as immediate-release formulation with dosing of 20-80 mg twice daily or 10-40 mg 3-4 times daily 1, 3
Atenolol: While often considered once-daily dosing, it has immediate onset with peak blood levels reached between 2-4 hours after ingestion 4
Esmolol: Administered intravenously with very short half-life (9 minutes), used primarily in acute settings 1

When selecting an immediate-acting beta blocker, consider these pharmacokinetic properties:

Metoprolol tartrate: Rapid absorption with peak effect in 2-4 hours, half-life of 3-4 hours, requiring twice daily dosing for consistent effect 1, 2
Propranolol: Immediate release formulation has a half-life of 3-6 hours, requiring multiple daily doses 1, 5
Atenolol: Despite being immediate-acting, has longer half-life (6-7 hours) with effects persisting for 24 hours, making it less suitable when a shorter duration is desired 4

The choice between immediate-acting beta blockers should be based on:

Cardioselectivity: Metoprolol and atenolol are beta-1 selective, making them preferable in patients with reactive airway disease 1, 6
Duration of action: Metoprolol tartrate provides shorter duration than atenolol, allowing for more flexible dosing 2, 4
Metabolism: Metoprolol undergoes hepatic metabolism while atenolol is primarily eliminated unchanged by the kidneys, making metoprolol preferable in patients with renal impairment 4, 2
Onset of action: Both metoprolol and propranolol have rapid onset, with significant beta-blockade occurring within 1 hour 1, 2

For immediate-acting beta blockade:

Metoprolol tartrate: Start with 25-50 mg twice daily, can be titrated up to 100 mg twice daily 1, 7
Propranolol: Start with 10-40 mg three to four times daily 1, 5
Atenolol: Though immediate-acting, its longer half-life makes it less suitable when shorter duration is needed 4

Patients with asthma or COPD: Use cardioselective agents like metoprolol at reduced doses (e.g., 12.5 mg) rather than avoiding beta blockers completely 1, 7
Patients with heart failure: Avoid immediate initiation of beta blockers in acute decompensated heart failure 1, 7
Contraindications: Marked first-degree AV block (PR interval >0.24s), second or third-degree heart block without pacemaker, severe hypotension (SBP <90 mmHg), or significant bradycardia (HR <50 bpm) 1, 7

Abrupt discontinuation: Never abruptly stop beta blockers as this can lead to rebound hypertension or tachycardia 1
Combining with other AV nodal blocking agents: Can lead to profound bradycardia 1, 7
Use in pre-excited atrial fibrillation: Beta blockers should be avoided as they may accelerate ventricular response 1, 7