isoproterenol

Absorption: IV administration results in complete bioavailability.

Distribution: Unknown.

Metabolism/Excretion: Metabolism occurs in the lung, liver, and other tissues; 50% excreted unchanged by the kidneys.

Half-Life: 2.5–5 min.

Time/Action Profile ⬆ ⬇

(bronchodilation)

ROUTE	ONSET	PEAK	DURATION
IV	immediate	unknown	<1 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to adrenergic amines or bisulfites.

Use Cautiously in:

Cardiovascular disease (including hypertension and coronary artery disease);
Hyperthyroidism;
Diabetes;
Glaucoma;
Pedi: Safety and effectiveness not established in children;
Geri: Older adults are more susceptible to adverse reactions; may require dose .

Adv. Reactions/Side Effects ⬆ ⬇

CV: angina, hypertension, tachycardia, ARRHYTHMIAS

Endo: hyperglycemia

GI: nausea, vomiting, xerostomia

Neuro: nervousness, restlessness, tremor, headache, insomnia

Misc: pink/red discoloration of saliva

Interactions ⬆ ⬇

Drug-drug:

Concurrent use with other adrenergic agents (sympathomimetics) will have additive adrenergic side effects.
Use with MAO inhibitors may lead to hypertensive crisis.
May increase theophylline elimination.
Beta blockers may negate therapeutic effect.

Route/Dosage ⬆ ⬇

IV (Adults ): Bradycardia or AV block: 1–20 mcg/min continuous infusion; Bronchospasm during anesthesia: 10–20 mcg, repeated as needed.

Availability ⬆ ⬇

(Generic available)

Solution for injection: 200 mcg (0.2 mg)/mL

Assessment ⬆ ⬇

Bronchodilator: Assess lung sounds, respiratory pattern, pulse, and BP before administration and during peak of medication. Note amount, color, and character of sputum produced.
Monitor pulmonary function tests before initiating therapy and periodically during therapy to determine effectiveness.
Pedi: Continuous assessment of vital signs, frequent electrocardiography, and daily measurements of cardiac enzymes, including CK-MB, are required if IV isoproterenol therapy is administered to pediatric patients. May cause myocardial necrosis, HF, and death. Risks of cardiac toxicity may be increased by acidosis, hypoxemia, coadministration of corticosteroids, coadministration of theophylline, or aminophylline.

Lab Test Considerations:

May cause transient ↓ in serum potassium concentrations with nebulization or at higher than recommended doses.

Toxicity and Overdose:

Symptoms of overdose include persistent agitation, chest pain or discomfort, decreased BP, dizziness, hyperglycemia, hypokalemia, seizures, tachyarrhythmias, persistent trembling, and vomiting.
- Treatment includes discontinuing beta-adrenergic agonists and symptomatic, supportive therapy. Cardioselective beta blockers are used cautiously, as they may induce bronchospasm.

Implementation ⬆ ⬇

IV vasoactive medications are inherently dangerous. Prior to administration, have second practitioner independently check original order, dose calculations, concentration, route of administration, and infusion pump settings.

IV Administration:

Dilute 1 mL (0.2 mg) to 10 mL with 0.9% NaCl or D5W. Do not use if solution is pinkish to brownish or contains a precipitate.
Rate: Administer 0.5–1 mL (10–20 mcg) over 1 min.
Diluent: Prepare by adding 5 mg (20 mL of 0.2 mg/mL solution) of isoproterenol to 500 mL of D5W, D10W, 0.9% NaCl, 0.45% NaCl, dextrose/saline combinations, dextrose/Ringer’s or lactated Ringer’s combinations, Ringer’s or LR. Use diluted solution immediately. Discard unused solution. Concentration: 8 mcg/mL.
Rate: Administer at a rate of 0.5–5 mcg/min (15–75 mL/hr), adjusting according to patient response and parameters for heart rate and hemodynamic values. Administer via infusion pump to delivery of precise amounts of medication. Infusion must be gradually tapered over a 24- to 48-hr period to prevent rebound bronchospasm.

Patient/Family Teaching ⬆ ⬇

Explain purpose of isoproterenol to patient.
Advise patient to consult health care professional before taking any OTC medications or alcoholic beverages concurrently with this therapy. Caution patient also to avoid smoking and other respiratory irritants.
Instruct patient to contact health care professional immediately if shortness of breath is not relieved by medication or is accompanied by diaphoresis, dizziness, palpitations, or chest pain.
Rep: Isoproterenol usually inhibits spontaneous or oxytocin-induced contractions of the pregnant human uterus and may delay the second stage of labor. Avoid isoproterenol during the second stage of labor. Avoid isoproterenol in obstetrics when maternal blood pressure exceeds 130/80 mmHg.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇