ISOPROTERENOL HYDROCHLORIDE
ISOPROTERENOL HYDROCHLORIDE  (eye-soe-proe-ter'e-nole)  Isuprel Classifications: beta-adrenergic agonist; bronchodilator; Therapeutic: bronchodilator; beta-adrenergic agonist Pregnancy Category: C |
Availability
Isoproterenol HCl: 0.2 mg/mL, 0.02 mg/mL injection
Action
Synthetic sympathomimetic amine that acts directly on beta1-adrenergic receptors with little or no effect on alpha-adrenoceptors. Stimulation of beta2-adrenoreceptors relaxes bronchospasm and, by increasing ciliary motion, facilitates expectoration of pulmonary secretions. Induces stimulation of beta1-adrenergic receptors and results in increased cardiac output and cardiac workload by increasing strength of contraction.
Therapeutic Effect
Effectiveness in bronchodilation reverses bronchospasm as well as facilitates removal of bronchial secretion. Increases cardiac output and cardiac workload.
Uses
Reversible bronchospasm induced by anesthesia. As cardiac stimulant in cardiac arrest, carotid sinus hypersensitivity, cardiogenic and bacteremic shock, Adams-Stokes syndrome, or ventricular arrhythmias. Used in treatment of shock that persists after replacement of blood volume.
Unlabeled Uses
Treatment of status asthmaticus in children.
Contraindications
Preexisting cardiac arrhythmias associated with tachycardia; tachycardia caused by digitalis intoxication, central hyperexcitability, cardiogenic shock secondary to coronary artery occlusion and MI; simultaneous administration with epinephrine, ventricular fibrillation; pregnancy (category C).
Cautious Use
Sensitivity to sympathomimetic amines; older adult and debilitated patients, hypertension, coronary insufficiency and other cardiovascular disorders, angina; renal dysfunction, hyperthyroidism, diabetes, prostatic hypertrophy, glaucoma, tuberculosis, during anesthesia by cyclopropane; lactation.
Route & Dosage
| Bronchospasm Adult: IV 0.01–0.02 mg prn Cardiac Arrhythmias/Cardiac Resuscitation Adult: IV 0.02–0.06 mg bolus, followed by 5 mcg/min infusion Child: IV 0.1 mcg/kg/min by continuous infusion Shock/Hypoperfusion Adult: IV 0.5–5 mcg/min |
Administration
Intravenous
PREPARE: Direct IV Injection for Adult with AV Block/Arrhythmia/Bradycardia: Dilute 1 mL (0.2) of 1:5000 solution with 9 mL NS or D5W to produce a 1:50,000 (0.02 mg/mL) solution or use 1:50,000 solution undiluted. Continuous Infusion for Adult with AV Block/Bradycardia: Dilute 10 mL (2 mg) of 1:5000 solution in 500 mL D5W to produce a 1:250,000 (4 mcg/mL) solution. IV Infusion for Adult with Shock Hypoperfusion: Dilute 5 mL (1 mg) of 1:5000 solution in 500 mL D5W to produce a 1:500,000 (2 mcg/mL) solution. Direct IV Injection for Adult with Bronchospasm: Dilute 1 mL (0.2 mg) of 1:5000 solution with 9 mL NS or D5W to produce a 1:50,000 solution undiluted. Continuous Infusion for Child with AV Block/Bradycardia: Dilute to a range of 4–12 mcg/mL in 100 mL of D5W or NS. ADMINISTER: Direct IV for Adult/Child: Give each 1 mL of 1:50,000 solution over 1 min. Flush with 15–20 mL NS. Continous IV Infusion for Adult/Child: Infusion rate is generally decreased or infusion may be temporarily discontinued if heart rate exceeds 110 bpm, because of the danger of precipitating arrhythmias. Microdrip or constant-infusion pump is recommended to prevent sudden influx of large amounts of drug. IV administration is regulated by continuous ECG monitoring. Patient must be observed and response to therapy must be monitored continuously. INCOMPATIBILITIES Solution/additive: Sodium bicarbonate, aminophylline, carbenicillin, diazepam, furosemide. |
- Isoproterenol solutions lose potency with standing. Discard if precipitate or discoloration is present.
Adverse Effects (≥1%)
CNS: Headache, mild tremors, nervousness, anxiety, insomnia, excitement, fatigue. CV: Flushing, palpitations, tachycardia, unstable BP, anginal pain, ventricular arrhythmias. GI: Swelling of parotids (prolonged use), bad taste, buccal ulcerations (sublingual administration), nausea. Other: Severe prolonged asthma attack, sweating, bronchial irritation and edema. Acute Poisoning: Overdosage, especially after excessive use of aerosols (tachycardia, palpitations, nervousness, nausea, vomiting).Interactions
Drug: Epinephrine and other sympathomimetic amines, tricyclic antidepressants increase effects and cause cardiac toxicity. halogenated general anesthetics exacerbate arrhythmias; while beta blockers antagonize effects.Pharmacokinetics
Absorption: Rapidly from parenteral administration. Onset: Immediate. Metabolism: Metabolized by COMT in liver, lungs, and other tissues. Elimination: 40–50% unchanged in urine.Nursing Implications
Assessment & Drug Effects
- Check pulse before and during IV administration. Rate >110 usually indicates need to slow infusion rate or discontinue infusion. Consult physician for guidelines. Incidence of arrhythmias is high, particularly when drug is administered IV to patients with cardiogenic shock or ischemic heart disease, digitalized patients, or to those with electrolyte imbalance.
- Note: Tolerance to bronchodilating effect and cardiac stimulant effect may develop with prolonged use.
- Note: Once tolerance has developed, continued use can result in serious adverse effects including rebound bronchospasm.
Patient & Family Education
- Before IV isoproterenol is administered, tell the physician if you have any of the following diseases: asthma, diabetes mellitus, overactive thyroid, phenocytoma, allergic reaction to this drug, if you are pregnant or trying to become pregnant, or if you are breastfeeding.
- Before the IV is initiated, tell the physician all of the medications that you are currently taking, including nutritional supplements and OTC medicines.
- If you are frequent user of caffeinated beverages, alcohol, or illegal drugs, tell your physician before the IV is started. All of these chemicals may interfere with the effectiveness of this drug.
Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; 
Canadian drug name; Prototype drug