A cardiac stimulant drug of the inotropic sympathomimetic group (see SYMPATHOMIMETIC DRUGS), dobutamine acts on sympathetic receptors in cardiac muscle, increasing the contractility and hence improving the cardiac output but with little e?ect on the cardiac rate. It is particularly useful in cardiogenic shock. It must be given by intravenous infusion. (See also HEART.)
n. an *inotropic *sympathomimetic drug (a ?1 agonist) used to increase the force of contraction of the ventricles and improve the heart output, for example in patients who have had a *myocardial infarction or in cases of septic shock. It is given by intravenous infusion.
adj. affecting the contraction of heart muscle. Drugs such as *dobutamine, *dopamine, and *enoximone have positive inotropic action, stimulating heart muscle contractions and causing the heart rate to increase. *Beta-blocker drugs, such as *propranolol, have negative inotropic action, reducing heart muscle contractions and causing the heart rate to decrease.... inotropic
adj. having the effect of stimulating the *sympathetic nervous system. The actions of sympathomimetic drugs are adrenergic: they act on alpha or beta *adrenoceptors. Alpha-adrenergic stimulants (alpha agonists) stimulate alpha receptors. They include *vasoconstrictors (e.g. *ephedrine, *phenylephrine, *metaraminol), used to treat nasal congestion and severe hypotension, and the selective ?2 agonists *apraclonidine and *brimonidine, which are used in the treatment of glaucoma. Beta-adrenergic stimulants (beta agonists) stimulate ?1 and/or ?2 adrenoceptors. ?2 agonists such as *salbutamol, *salmeterol, and *terbutaline relax bronchial smooth muscle and are used as *bronchodilators. Some ?2 agonists, including salbutamol, relax uterine muscle and are sometimes used in the treatment of premature labour (see tocolytic). ?1 agonists (e.g. *dobutamine) stimulate ?1 receptors in the heart and are therefore used for their *inotropic effects.... sympathomimetic
Health Encyclopedia