NORISODRINE AEROTROL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NORISODRINE AEROTROL (NORISODRINE AEROTROL).
Isoproterenol is a non-selective beta-adrenergic receptor agonist, primarily stimulating both β1 and β2 receptors, resulting in increased heart rate, myocardial contractility, and bronchodilation.
| Metabolism | Primarily via hepatic metabolism by catechol-O-methyltransferase (COMT) and sulfation; also metabolized by monoamine oxidase (MAO) to a lesser extent. |
| Excretion | Primarily renal excretion of unchanged drug and metabolites (sulfate conjugates). After intravenous administration, approximately 70-80% of the dose is excreted in urine within 24 hours, with less than 10% in feces. |
| Half-life | The terminal elimination half-life of isoproterenol is approximately 2-3 minutes following intravenous administration, due to rapid uptake into tissues and metabolism by catechol-O-methyltransferase (COMT). This short half-life necessitates continuous infusion for sustained effect. |
| Protein binding | Approximately 50-60% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.3-0.5 L/kg, indicating distribution primarily into extracellular fluid and rapid uptake into tissues. |
| Bioavailability | Inhalation: approximately 10-20% due to local deposition and absorption; Oral: negligible (<5%) due to extensive first-pass metabolism in the gut wall and liver; Sublingual: approximately 5-10%. |
| Onset of Action | Intravenous: immediate (within 30-60 seconds); Inhalation: 1-2 minutes; Sublingual: 10-15 minutes. |
| Duration of Action | Intravenous: 5-10 minutes (due to rapid clearance); Inhalation: 30-60 minutes; Sublingual: 1-2 hours. Duration is limited by rapid metabolism and redistribution. |
1 to 2 inhalations (0.08 to 0.16 mg) every 4 to 6 hours as needed for bronchospasm.
| Dosage form | DISC |
| Renal impairment | No specific dose adjustment required; use with caution in severe renal impairment. |
| Liver impairment | No specific dose adjustment required; use with caution in severe hepatic impairment. |
| Pediatric use | Children 6-12 years: 1 inhalation (0.08 mg) every 4 to 6 hours as needed. Children <6 years: not recommended. |
| Geriatric use | Start at lower end of dosing range; monitor for cardiovascular effects. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NORISODRINE AEROTROL (NORISODRINE AEROTROL).
| Breastfeeding | Excreted in breast milk in small amounts; M/P ratio not established. Potential for infant tachycardia and irritability. Caution and consider alternative therapies. |
| Teratogenic Risk | FDA Pregnancy Category C. First trimester: No adequate human studies; animal studies show teratogenicity at high doses. Second and third trimesters: Risk of fetal tachycardia, hypoglycemia, and potential for preterm labor due to beta-2 agonist effects. Use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to isoproterenol or any component","Tachyarrhythmias (e.g., ventricular tachycardia)","Digitalis toxicity-induced arrhythmias","Angle-closure glaucoma"]
| Precautions | ["May cause cardiac arrhythmias, including ventricular arrhythmias","Use with caution in patients with pre-existing cardiac disease, hypertension, or hyperthyroidism","May exacerbate angina or myocardial ischemia","Risk of paradoxical bronchospasm with excessive use in asthma"] |
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| Monitor maternal heart rate, blood pressure, and serum potassium. Fetal monitoring for heart rate and uterine activity. Assess for signs of pulmonary edema. |
| Fertility Effects | No known adverse effects on fertility in human studies; animal studies show no significant impairment. |