LEVALBUTEROL HYDROCHLORIDE

Clinical safety rating: safe

Animal studies have demonstrated safety

How it works

Levalbuterol is a beta-2 adrenergic receptor agonist that promotes bronchodilation by increasing intracellular cyclic AMP in bronchial smooth muscle, leading to relaxation. It is the (R)-enantiomer of albuterol, which has higher affinity for beta-2 receptors than the (S)-enantiomer.

What the body does with it

Metabolism	Primarily metabolized by sulfotransferase (SULT1A3) in the liver and gastrointestinal tract to an inactive sulfate conjugate. Negligible metabolism via CYP450 enzymes.
Excretion	Primarily renal; approximately 75-88% of an administered dose is excreted as glucuronide conjugates and unchanged drug in urine, with less than 5% excreted in feces.
Half-life	The terminal elimination half-life is approximately 3.3-4 hours (range 2.5-5.5 hours) in adults. In patients with hepatic impairment, half-life may be prolonged; no significant change in renal impairment.
Protein binding	Approximately 45-60%, primarily to albumin and alpha-1-acid glycoprotein.
Volume of Distribution	Approximately 2.0-2.5 L/kg in healthy adults, indicating extensive distribution into tissues, consistent with a hydrophilic compound that distributes into extracellular fluid.
Bioavailability	Oral: low (<1%) due to extensive first-pass metabolism. Inhaled: approximately 10-25% systemic bioavailability from the lung; the remainder is swallowed and undergoes first-pass metabolism.
Onset of Action	Via nebulization: within 5-15 minutes. Via metered-dose inhaler: within 5-10 minutes. Via subcutaneous injection: within 5-10 minutes.
Duration of Action	3-6 hours by inhalation; 4-6 hours by subcutaneous route. Bronchodilation effect wanes after 3 hours; some patients may require more frequent dosing.

Classification & Brands

Dosing & administration

0.63-1.25 mg via nebulization every 8 hours, up to 4 times daily as needed.

Dosage form	SOLUTION
Renal impairment	No dosage adjustment required based on GFR.
Liver impairment	No specific dosage adjustment recommended; use with caution in severe hepatic impairment.
Pediatric use	Children 6-11 years: 0.31 mg via nebulization every 8 hours; children ≥12 years: 0.63-1.25 mg every 8 hours.
Geriatric use	No specific dose adjustment; monitor for adverse effects due to potential comorbidities.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Beta-blockers may antagonize the effects Can cause paradoxical bronchospasm and cardiovascular effects.

Breastfeeding

It is not known whether levalbuterol is excreted in human breast milk. Due to the potential for serious adverse reactions in nursing infants (e.g., tachycardia, irritability), caution is advised. The M/P ratio has not been determined. Consider the developmental and health benefits of breastfeeding along with the mother's clinical need for levalbuterol.

Teratogenic Risk

Pregnancy Category C. In animal studies, levalbuterol caused adverse effects on fetal development (e.g., increased fetal resorption, cleft palate) at high doses. No well-controlled human studies exist. beta-agonist use in pregnancy, particularly during the first trimester, has been associated with a small increased risk of gastroschisis and other congenital anomalies in some epidemiologic studies, but data are inconsistent. During the second and third trimesters, beta-agonists may cause maternal tachycardia, hyperglycemia, and potential fetal tachycardia; use only if clearly needed.

Warnings & precautions

■ FDA Black Box Warning

No FDA black box warning.

Side Effect Profile

Common Effects	bronchospasm
Serious Effects

Absolute Contraindications

["Hypersensitivity to levalbuterol, albuterol, or any component of the formulation"]

Clinical Precautions

Precautions

["Paradoxical bronchospasm may occur; discontinue immediately if it occurs","Cardiovascular effects including increased heart rate, blood pressure, and arrhythmias; use with caution in patients with cardiovascular disorders","Hypersensitivity reactions, including urticaria, angioedema, and anaphylaxis","Excessive use may lead to worsening asthma and potentially fatal outcomes","Hypokalemia may occur with high doses","Use with caution in patients with hyperthyroidism, diabetes mellitus, or seizure disorders"]

Clinical Tips & Counseling

Drug interactions

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