RecruitingPhase 4Drug trialStudy to Determine the Pharmacokinetics and Pharmacodynamic Effects of Phenylephrine on BP Via IVThe primary objective of this study is to evaluate the dose effect of Phenylephrine Hydrochloride Injection on the treatment of clinically relevant decreased blood pressure in the pediatric population, ≥12 to 16 year old patients undergoing general and neuraxial anesthesia. The secondary objectives are to describe changes in blood pressure and heart rate, time to onset and to maximal response, and the duration of response; to assess the safety of the product in this population; and to characterize the pharmacokinetics of phenylephrine hydrochloride.