This is an old revision of the document!

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

β2 adrenergic receptor (active R-isomer)

Cellular Effects

↑ cAMP
Smooth muscle relaxation
↓ mast cell mediator release
↑ mucociliary clearance

Systemic Effect

Drives potassium intracellularly

Net effect:

Rapid bronchodilation

Indications

Acute asthma symptoms
COPD rescue therapy
Alternative when albuterol causes tachycardia

Often substituted for:

Albuterol

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:

More β2 selective
Less tachycardia/tremor (sometimes)
Higher cost
No clear superiority in outcomes