Levalbuterol (Xopenex®)

Levalbuterol
Brand Name Xopenex®
Drug Class Short-Acting β2 Agonist (SABA)
Primary Indication Acute bronchospasm
Receptor Target β2 adrenergic receptor (R-isomer)
Mechanism ↑ cAMP → Bronchodilation
Onset ~3–5 minutes
Duration 4–6 hours
Route Inhaled (MDI, Neb)
Potassium Effect ↓ Serum K⁺ (cellular shift)
FDA Approval 1999

Overview

Levalbuterol is the purified R-enantiomer of albuterol, designed to provide bronchodilation with fewer adrenergic side effects.

In practice, it produces similar clinical outcomes to Albuterol but may cause less tachycardia and tremor in some patients.

It is often used when patients cannot tolerate albuterol due to palpitations.

Mechanism of Action

Receptor Activated

Cellular Effects

Systemic Effect

Net effect:

Indications

Often substituted for:

Contraindications

Absolute:

  • Hypersensitivity

Relative / Caution:

  • Tachyarrhythmias
  • Ischemic heart disease
  • Hyperthyroidism

Dosing

MDI:

  • 1–2 puffs every 4–6 hours PRN

Nebulizer:

  • 0.63–1.25 mg every 6–8 hours PRN

Pharmacokinetics

Onset:

  • 3–5 minutes

Peak:

  • ~30 minutes

Duration:

  • 4–6 hours

Elimination:

  • Hepatic metabolism and renal excretion

Adverse Effects

Adrenergic:

  • Tremor (less than albuterol)
  • Tachycardia (less than albuterol)
  • Palpitations
  • Anxiety

Metabolic:

  • Hypokalemia

Overall:

  • Similar profile but often better tolerated

Drug Interactions

Beta-blockers:

  • Reduced bronchodilation

Stimulants:

  • Increased tachycardia risk

Diuretics:

  • Increased hypokalemia

Monitoring

  • Symptom relief
  • Heart rate
  • Rescue inhaler frequency

Clinical Pearls

  • Same efficacy as albuterol
  • Fewer side effects in some patients
  • Much higher cost
  • Often chosen in pediatrics or tachycardia intolerance

Comparison Within Class

Compared to Albuterol: