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. |
| Molecular Weight | 239.31 |
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 | Levalbuterol is generally avoided in the first trimester unless benefit outweighs risk; animal studies have shown adverse effects at high doses. |
| 2nd trimester | May be used if clearly needed; beta-agonists have been associated with mild fetal tachycardia and hypoglycemia, but no major teratogenic risk. |
| 3rd trimester | May cause uterine relaxation and delay labor; use with caution near term. Monitor for maternal tachycardia and fetal distress. |
Clinical note
Comprehensive clinical and safety monograph for XOPENEX (XOPENEX).
| Placental transfer | Levalbuterol crosses the placenta; concentrations in cord blood are approximately 30% of maternal levels. |
| Breastfeeding | Levalbuterol is excreted into breast milk in small amounts; however, due to poor oral bioavailability, systemic levels in the infant are likely negligible. Use with caution in nursing mothers, especially in preterm infants or those with cardiovascular conditions. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to levalbuterol or any component of the formulationHypersensitivity to 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 |
| Food/Dietary | No clinically significant food interactions. Avoid excessive caffeine intake as it may increase stimulant effects (e.g., tremor, tachycardia). |
| Clinical Pearls |
Loading safety data…
| Lactation Rating | L2 (Safer) |
| 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. |
| 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). |
| Levalbuterol (Xopenex) is the R-enantiomer of racemic albuterol, potentially offering fewer beta-adrenergic adverse effects like tachycardia at equipotent doses. However, clinical relevance is debated; cost often limits use. It is administered via nebulization or HFA inhaler; the HFA inhaler does not contain a dose counter, so manual tracking is required. Onset within 10-15 minutes, duration 4-6 hours. Caution in patients with cardiovascular disorders, hyperthyroidism, seizures, or diabetes. Contraindicated in hypersensitivity to levalbuterol or albuterol. |
| Patient Advice | Use only as directed; do not increase dose or frequency without consulting your doctor. · Rinse mouth with water after each use to prevent oral thrush (if using inhaled corticosteroid combination, though Xopenex alone does not require this). · Seek emergency care if symptoms worsen or if you need more than 3 treatments per day or more than 1 canister per month. · Store inhaler at room temperature away from heat and open flame. Do not puncture or incinerate. · Monitor for tachycardia, palpitations, chest pain, headache, nervousness, or tremor; report severe or persistent symptoms. |