Details About Overdose or Poisoning Generic Salt :: Isoproterenol
Isoproterenol
Drug Pharmacology ::
I. Pharmacology. Isoproterenolis a catecholamine-like drug that stimulates beta-adrenergic receptors(beta-1 and -2). Its pharmacologic properties include positiveinotropic and chronotropic cardiac effects, peripheral vasodilation,and bronchodilation. Isoproterenol is not absorbed orally and showsvariable and erratic absorption from sublingual and rectal sites. Theeffects of the drug are terminated rapidly by tissue uptake andmetabolism; effects persist only a few minutes after intravenousinjection.
Drug Indications ::
Indications
Severe bradycardia or conduction block resulting in hemodynamically significant hypotension (see Hypotension). Note:After beta-blocker overdose, even exceedingly high doses ofisoproterenol may not overcome the pharmacologic blockade of betareceptors, and glucagon (see Glucagon) is the preferred agent.
Toincrease heart rate and thereby abolish polymorphous ventriculartachycardia (torsade de pointes) associated with QT intervalprolongation (see Ventricular arrhythmias).
Drug Contra-Indications ::
III. Contraindications./b>
Do not use isoproterenol for ventricular fibrillation or ventricular tachycardia (other than torsade de pointes).
Use with extreme caution in the presence of halogenated or aromatic hydrocarbon solvents or anesthetics or chloral hydrate.
Drug Adverse Effects ::
IV. Adverse effects
Increased myocardial oxygen demand may result in angina pectoris or acute myocardial infarction.
Peripheral beta-2-adrenergic–mediated vasodilation may worsen hypotension.
The drug may precipitate ventricular arrhythmias.
Sulfite preservative in some parenteral preparations may cause hypersensitivity reactions.
E. Hypokalemia may occur secondary to beta-2-adrenergic–mediated intracellular potassium shift.
F. Use in pregnancy. FDAcategory C (indeterminate). This does not preclude its acute,short-term use for a seriously symptomatic patient (see Table III–1).However, it may cause fetal ischemia and also can reduce or stoputerine contractions.
Drug Lab Interactions ::
Drug or laboratory interactions
Additive beta-adrenergic stimulation occurs in the presence of other sympathomimetic drugs, theophylline, and glucagon.
Administrationin the presence of cyclopropane, halogenated anesthetics, or otherhalogenated or aromatic hydrocarbons may enhance the risk ofventricular arrhythmias because of sensitization of the myocardium tothe arrhythmogenic effects of catecholamines.
Digitalis-intoxicated patients are more prone to develop ventricular arrhythmias when isoproterenol is administered.
Beta blockers may interfere with the action of isoproterenol by competitive blockade at beta-adrenergic receptors.
Drug Dose Management ::
Dosage and method of administration
For intravenous infusion, use a solution containing 4 mcg/mL (dilute 5 mL of 1:5,000 solution in 250 mL D5W),and begin with 0.5–1 mcg/min infusion (children, 0.1 mcg/kg/min) andincrease as needed for desired effect or as tolerated (by monitoringfor arrhythmias). For emergency treatment, the infusion rate may startat 5 mcg/min. The usual upper dosage is 20 mcg/min (1.5 mcg/kg/min inchildren), but as much as 200 mcg/min has been given in adults withpropranolol overdose. Preparations will degrade (and turn dark) withexposure to light, air, or heat.
ForIV bolus, the usual adult dose is 20–60 mcg (1–3 mL of a 1:50,000solution) and repeat bolus doses of 10–200 mcg. If a dilute solution isnot available, make a solution of 1:50,000 (20 mcg/mL) by diluting 1 mLof the 1:5000 solution to a volume of 10 mL with normal saline or D5W.
Drug Chemical Formulations ::
Formulations
Parenteral. Isoproterenolhydrochloride (Isuprel, others), 20 mcg/mL (1:50,000) in 10 mL withneedle or 200 mcg/mL (1:5,000) in 1- and 5-mL amps and 5- and 10-mLvials, which all contain sodium bisulfite or sodium metabisulfite as apreservative.
The suggested minimum stocking level to treat a 70-kg adult for the first 24 hours is 10 (10-mL) vials.
