M A Frye — Page 4 | Search PubMed

PubMedDate not supplied

Neuroleptic exposure in bipolar outpatients in a research setting.

The study purpose was to determine the extent of neuroleptic exposure in bipolar outpatients maintained on mood-stabilizing medications and any clinical correlates associated with this exposure. Data on medication and severity of illness were gathered from the records (prospective and retrospective) of 70 bipolar patients involved in outpatient research studies at the National Institute of Mental Health (NIMH). The percentage of patients requiring neuroleptic treatment, percentage of time on neuroleptics during the period of observation, total dose of neuroleptics in chlorpromazine (CPZ) equivalency, and number of neuroleptic trials were among the variables calculated. Regression analyses and analyses of variance (ANOVAs) were performed to assess the relationships between neuroleptic exposure and clinical course. Forty-five patients (64.3%) had a neuroleptic trial during the prospective study. Subjects exposed to neuroleptics spent, on average, 15.4% (median, 6.0%) of the time in study on neuroleptic treatment, and were administered, on average, a total of 11,770.5 mg (median, 1,621.9 mg) of neuroleptics (in CPZ equivalency) per year in the prospective study. As expected, bipolar I compared with bipolar II patients had significantly higher neuroleptic exposure by a number of measures. The number of hospitalizations for mania prior to study entry was associated with greater prospective neuroleptic use during the study. Despite maintenance treatment with one or more moodstabilizing agents, we found a relatively high need for adjunctive neuroleptic medication even in this sample of high-functioning bipolar outpatients. These results highlight the need for the study of alternatives, as well as more effective primary mood-stabilizing agents.

Adult↗

PubMedDate not supplied

A comparison of dobutamine infusion to exercise as a cardiac stress test in healthy horses.

This study was done to determine whether administration of dobutamine would produce echocardiographic and electrocardiographic alterations comparable to those induced by treadmill exercise in healthy horses. Fourteen horses received maximal treadmill exercise and, separately, intravenous dobutamine infusion up to a maximum rate of 50 microg/kg/min. Ten of the 14 horses were euthanized, and the myocardial tissues were examined grossly and histopathologically. No significant differences were found in the chronotropic effects of dobutamine and exercise (P = .905). Dobutamine induced greater interventricular septal thickening during systole (dobutamine = 4.78 cm, exercise = 4.03 cm; P = .004). and greater left ventricular diameters during diastole (dobutamine = 9.73 cm, exercise = 9.26 cm; P = .037), than did exercise treatment. Horses exhibited transient signs of sweating and restlessness during infusion of moderate to maximum doses of dobutamine. Ventricular ectopy seen in 11 of 14 horses was attributed to the arrhythmogenic properties of dobutamine, as well as to increased vagal tone present at low dobutamine doses. Myocardial lesions characteristic of catecholamine myotoxicity were present in 2 of the 10 horses examined. Although dobutamine induces chronotropic and inotropic changes similar to those induced by exercise, the use of high-dose dobutamine as a cardiac stressor in horses cannot be advocated because of potential development of arrhythmias or myotoxicity.

Adrenergic beta-Agonists↗