isoproterenolmedical dictionary


Synthetic beta-adrenergic agonist, causes peripheral vasodilation, bronchodilation and increased cardiac output. It possesses the cardiac excitatory, but not the vasoconstrictor, actions of epinephrine. Chemically it differs from epinephrine in having an isopropyl group replacing the methyl group attached to the nitrogen atom; used in the treatment of bronchial asthma and heart block, including Adams-Stokes attacks.

Pharmacologic action: Pure beta-adrenergic agonist. Inotropic and chronotropic effects increase heart rate and cardiac output. Blood pressure usually falls due to vasodilation.

Uses: Can be used to treat complete heart block and atropine refractory bradycardia, but it is not the drug of choice for either condition.

Dose: 2-10 mcg/min Start at 2 mcg/min and titrate to effect. Rarely need more than 10 mcg/min

Potential complications: arrhythmias, vasodilation causes hypotension and reduced coronary perfusion leading to myocardial ischaemia, at low doses it may be helpful for symptomatic bradycardias, but at higher doses it is harmful.

Note: Other inotropic agents that cause less arrhythmias and ischaemia are usually preferred

Chemical name: 3,4-Dihydroxy-alpha-[(isopropylamino)methyl]benzyl alcohol hydrochloride.

Synonyms: isoprenaline hydrochloride, isopropylarterenol hydrochloride.

(15 Mar 2000)