XOPENEX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for XOPENEX (XOPENEX).
Selective beta-2 adrenergic receptor agonist that relaxes bronchial smooth muscle by increasing intracellular cyclic AMP levels.
| Metabolism | Primarily metabolized by catechol-O-methyltransferase (COMT) and to a lesser extent by conjugation (sulfation and glucuronidation). |
| Excretion | Renal: 80-100% as unchanged drug and metabolites (approximately 60% as unchanged levalbuterol, 20% as inactive sulfate conjugate). Fecal: <5%. |
| Half-life | Terminal elimination half-life: 3.3-4.0 hours in adults. Clinically, twice-daily dosing is not recommended due to shorter half-life; every 4-6 hour dosing is standard for acute bronchodilation. |
| Protein binding | Approximately 50% reversibly bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 1.5-2.0 L/kg (adults). High Vd indicates extensive extravascular distribution, including lung tissue. |
| Bioavailability | Inhalation: 10-20% of delivered dose reaches the lungs; swallowed portion undergoes first-pass metabolism. Oral: very low systemic bioavailability due to extensive presystemic metabolism. Intravenous: 100%. |
| Onset of Action | Inhalation: 5-15 minutes (nebulized or MDI). |
| Duration of Action | Inhalation: 3-6 hours (nebulized), up to 6 hours (MDI). Note: Not a maintenance therapy; use as needed for acute symptoms. |
Nebulized solution: 0.63 mg or 1.25 mg 3 times daily every 6-8 hours; metered-dose inhaler: 2 inhalations (90 mcg per inhalation) 3 times daily every 6-8 hours.
| Dosage form | SOLUTION |
| Renal impairment | No specific dose adjustment recommended; use with caution in severe renal impairment. |
| Liver impairment | No specific dose adjustment recommended; use with caution in severe hepatic impairment. |
| Pediatric use | Nebulized: 0.31-0.63 mg 3 times daily every 6-8 hours for age 6-11 years; 0.63-1.25 mg 3 times daily for age ≥12 years. Weight-based: 0.01-0.02 mg/kg/dose (max 1.25 mg) every 6-8 hours. |
| Geriatric use | Start at lower end of dosing range (e.g., 0.63 mg nebulized 3 times daily) due to potential for decreased renal function and increased adverse effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for XOPENEX (XOPENEX).
| Breastfeeding | Excreted in breast milk in small amounts; M/P ratio not established. Caution advised; consider developmental benefits of breastfeeding and maternal need for drug. |
| Teratogenic Risk | Pregnancy Category C. No adequate studies in pregnant women. In animal reproduction studies, levalbuterol caused fetal harm at high doses. Risk cannot be ruled out. First trimester: potential risk based on animal data; second and third trimesters: may inhibit uterine contractions and cause maternal tachycardia, hyperglycemia, and fetal tachycardia. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to levalbuterol or any component of the formulation","History of hypersensitivity to racemic albuterol"]
| Precautions | ["Paradoxical bronchospasm may occur with excessive use","Cardiovascular effects: increased heart rate, blood pressure, or ECG changes","Hypokalemia may occur with high doses","Immediate hypersensitivity reactions: urticaria, angioedema, rash"] |
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| Fetal Monitoring |
| Monitor maternal heart rate, blood pressure, and serum glucose. Fetal heart rate monitoring recommended, especially in third trimester. Assess for signs of preterm labor or uterine atony. |
| Fertility Effects | No human data on fertility effects. Animal studies showed no impairment of fertility at doses up to 50 mg/kg/day (approximately 270 times the maximum recommended human inhalation dose). |