Isoprenaline and orciprenaline activate both beta-1 and beta-2 adrenergic receptors.
- Isoprenaline
Because of both beta-1 and beta-2-mimetic effects, isoprenaline, also called isoproterenol, has, in addition to its action on smooth muscles, a cardiac stimulant effect.
The effect on smooth muscles consists of bronchodilatation, inhibition of uterine contractions and vasodilation (beta-2).
On the heart, isoprenaline has positive inotropic, chronotropic, bathmotropic and dromotropic effects and increases cardiac output.
Its effect on blood pressure depends on the relative importance of cardiac beta-1 effect tending to increase it and the vascular beta-2 effect lowering it.
It raises glycemia and plasma free fatty acids levels.
Because of its non specific effects, isoprenaline is not used any more in the treatment of asthma, its only therapeutic indications are cardiovascular: bradycardia, Stokes-Adams syndrome (atrioventricular block), shocks.
- Orciprenaline
Orciprenaline, also called metaproterenol, has pharmacological properties similar to that of isoprenaline but a longer action.
Metaproterenol |
ALUPENT* Inhalation |
The most frequent adverse effects of these agonists are headache, tremors, palpitations, tachycardia.
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