Evaluation of the pharmacodynamics and pharmacokinetics of ritodrine when administered as a loading dose. On establishing a potentially useful drug administration regimen in cases of fetal distress.

摘要: Inhibition of labor during the intrapartum period has been suggested as a method managing acute fetal distress. In such cases, rapid tocolysis is desirable but, in high doses, beta-adrenergic-receptor agonists, ritodrine, may cause severe maternal hypotension that could aggravate existing We undertook present study to establish safe infusion protocol for ritodrine achieves plasma concentration rapidly. Twelve nonpregnant female volunteers received, on separate days, three infusions is, 1, 2, and 3 mg, 2-minute period. The peak measured by high-performance liquid chromatography with electrochemical detection averaged 37, 74, 100 ng/ml after mg respectively. Ritodrine concentrations decreased rapidly dose was only 14 15 minutes. elimination phase half-life 6.11 hours. None doses significantly affected systolic blood pressure but increased heart rate glucose level diastolic potassium concentration. Even at highest rate, maximal changes cardiovascular metabolic variables were short-lived clinically modest; 29 bpm, 8 mm Hg, 26 mg/dl, 0.6 mEq/L. These data indicate can be achieved without serious side effects.