@article{oai:ir.kagoshima-u.ac.jp:00012178,
 author = {椙山, 加綱 and SUGIYAMA, Kazuna},
 journal = {鹿児島大学歯学部紀要},
 month = {Mar},
 note = {Vasoconstrictors, such as epinephrine and norepinephrine, are commonly contained in local anesthetics to decrease systemic toxicity and prolong the duration of action by retarding anesthetic absorption. These catecholamines have varying degrees of α and β adrenergic effects, resulting in cardiac and hemodynamic changes. On the other hand, several investigators have reported that clinical doses of these drugs have little effects on cardiovascular system, as far as they are evaluated with such conventional parameters as heart rate and blood pressure. Thus, the problems about the permissible doses of catecholamines contained in local anesthetics in dentistry have been still in controversy. In recent years, however, detailed studies have clarified that catecholamines, even if in clinical doses, cause marked circulatory changes beyond expectation. Our date using echocardiography dernonstrated that 45 μg of epinephrine contained in lidocaine caused significant increases in heart rate and stroke volume with a resultant increase in cardiac output. Tachycardia was due to the action of epinephrine on β_1 receptors of the pacemaker cells. The increase in stroke volume was caused by an augmentation of myocardial contractility and a decrease in afterload. Mean blood pressure was relatively stabilized because of a reduction in total peripheral resistance in spite of the increase in cardiac output. In contrast to epinephrine, more than 72 μg of norepinephrine contained in lidocaine produced a remarkable increase in total peripheral resistance and corresponding elevation in mean blood pressure. The reason for this was that norepinephrine stimulated α_1 receptors of vessels in skeletal muscle, thus leading to vasoconstriction. The elevation in mean blood pressure brought about the negative chronotropic and inotropic changes of the heart through the baroreceptor reflex. Felypressin, non-adrenergic vasoconstrictor, has been believed to have no direct effects on the heart, although it is less effective than epinephrine in prevention of bleeding and anesthetic potency. For that reason, anesthetics containing felypressin are usually used by choice in dental patients with cardiovascular disease. However, a large dose of felypressin has been reported to constrict coronary artery. Recent investigations indicate that felypressin has distinct effects on circulation and a depressant effect on cardiac function in ischemic heart. Consequently, the doses of epinephrine and norepinephrine contained in local anesthetics should be less than 45 and 72 μg, respectively. In cardiac patients, the administration of low concentration of epinephrine might be necessary according to the degree of severity of the disease.},
 pages = {1--11},
 title = {歯科用局所麻酔薬と血管収縮薬},
 volume = {16},
 year = {1996}
}