Isoproterenol side effects

One such example, the imide XIV (CP-27,987, Pfizer), has been studied in the clinic with what appears to be some initial success (131). This compound when administered by aerosol (6-140 pg) induced an effect and duration of action similar to that of isoproterenol. Side-effects included headaches and a transient increase in heart rate at the higher doses. A mild irritation of the throat and some coughing was noted at all doses, but these effects also were induced by the vehicle without drug. 

Because of the widespread nature of adrenoceptors, nonselective P-agonists can produce many undesirable side effects. Therefore, before adrenergic agonists could become widely used in the treatment of asthma, some selectivity in action was needed. Whereas epinephrine and ephedrine have significant agonist activity at both a and P adrenoceptors, isoproterenol is a selective agonist at the P receptor (39). However, isoproterenol does not distinguish between the P and receptors and it is not active orally. 

Anticholinergics — Although the precise role of anticholinergics in the treatment of asthma is not yet known, they have been advocated as an alternative to -agonist therapy in patients with cardiac arrhythmias or angina. Ipratropium bromide (14) (Sch. 1000, Atrovent ) by inhalation showed bronchodilator activity comparable with isoproterenol, but had a longer duration of action (4 hr.) with no significant side effects. ... 

The p agonist isoproterenol effectively decreases pulmonary artery pressure when administered intravenously in acute studies. Long-term studies with sublingual isoproterenol appear to show beneficial effects, but only in a limited number of patients. Since isoproterenol is not a selective pulmonary vasodilator, however, cardiovascular side effects are common. 

Albuterol (ventoun, proventil, others) is a selective P2 agonist with pharmacological properties and therapeutic indications similar to those of terbutaline. It is administered by inhalation or orally for the symptomatic relief of bronchospasm. When administered by inhalation, terbutaline produces significant bronchodilation within 15 minutes effects persist for 3-4 hours. Cardiovascular effects of albuterol are considerably weaker than those of isoproterenol that produce comparable bronchodilation when administered by inhalation. Oral albuterol may delay preterm labor. Rare CNS and respiratory side effects are sometimes observed. 

Isoproterenol (Pj = P )- bronchospasm, heart block, and bradyarrhythmias. Side effects include flushing, angina, arrhythmias. 

The most severe side effect of Isoproterenol is its cardiac stimulant effect. 

Structural analogues of epinephrine and isoproterenol continue to be synthesized and evaluated in the search for agents with fewer systemic side effects and better duration of action than the prototype catecholamines, Salbutamol (V) is representative of a new group of 3-adrenerglc... 

While the inhibition of noradrenaline re-uptake exerts predominantly an a-adrenergic effect, a selective jS-adrenergic effect can not be obtained by such an indirect mechanism. All selective /3-sympathomi-metics activate the receptors, P -, P2- or both sub-types, directly. The first pure jS-sympathomimetic in clinical use was isoproterenol which is structurally identical to adrenaline except the methyl-moiety at the N-position in the side-chain is replaced by an isopropyl-group. All effects produced by isoproterenol are due to either P -or 62-adrenoceptor stimulation tachycardia, increased stroke volume, decreased vascular resistance, broncho dilatation and, in pregnancy, uterus relaxation. The metabolic effects of isoproterenol are less pronounced than those of adrenaline. 

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