====== Levalbuterol (Xopenex®) ======

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<WRAP infobox>
^ Levalbuterol | {{ :respiratory:beta2_agonists:levosalbutamol.svg |}} |
| Brand Name | Xopenex® |
| Drug Class | [[respiratory:beta2_agonists:saba|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 |
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</WRAP>

===== 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 [[respiratory:beta2_agonists:albuterol|Albuterol]] but may cause less tachycardia and tremor in some patients.

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

<WRAP clear></WRAP>

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===== 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

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===== Indications =====

  * Acute asthma symptoms
  * COPD rescue therapy
  * Alternative when albuterol causes tachycardia

Often substituted for:
  * [[respiratory:beta2_agonists:albuterol|Albuterol]]

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<WRAP contra>
===== Contraindications =====

Absolute:
  * Hypersensitivity

Relative / Caution:
  * Tachyarrhythmias
  * Ischemic heart disease
  * Hyperthyroidism

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<WRAP details>
===== Dosing =====

MDI:
  * 1–2 puffs every 4–6 hours PRN

Nebulizer:
  * 0.63–1.25 mg every 6–8 hours PRN

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<WRAP details>
===== Pharmacokinetics =====

Onset:
  * 3–5 minutes

Peak:
  * ~30 minutes

Duration:
  * 4–6 hours

Elimination:
  * Hepatic metabolism and renal excretion

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<WRAP details>
===== Adverse Effects =====

Adrenergic:
  * Tremor (less than albuterol)
  * Tachycardia (less than albuterol)
  * Palpitations
  * Anxiety

Metabolic:
  * Hypokalemia

Overall:
  * Similar profile but often better tolerated

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<WRAP details>
===== Drug Interactions =====

Beta-blockers:
  * Reduced bronchodilation

Stimulants:
  * Increased tachycardia risk

Diuretics:
  * Increased hypokalemia

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<WRAP monitoring>
===== Monitoring =====

  * Symptom relief
  * Heart rate
  * Rescue inhaler frequency

</WRAP>

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<WRAP pearls>
===== Clinical Pearls =====

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

</WRAP>

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===== Comparison Within Class =====

Compared to [[respiratory:beta2_agonists:albuterol|Albuterol]]:
  * More β2 selective
  * Less tachycardia/tremor (sometimes)
  * Higher cost
  * No clear superiority in outcomes

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===== Related =====

  * [[respiratory:beta2_agonists|β2 Agonists]]
  * [[respiratory:beta2_agonists:albuterol|Albuterol]]
  * [[respiratory:asthma|Asthma]]
  * [[respiratory:copd|COPD]]