A composition comprised of an active agent that is 4-methoxy-N-(3,5-bis-(1-pyrrolidinyl)-4-hydroxy benzyl)benzene sulfonamide or a pharmaceutically acceptable salt thereof is intravenously administered to a subject, substantially evenly over a period of greater than about 15 minutes, to avoid disadvantageous hemodynamic effects, including systemic diastolic and systolic hypotension, to can occur with rapid intravenous or even short-term infusion administration of the active agent.