Nitroprusside.

Sodium nitroprusside has proved to be the most effective and best-tolerated vasodilator drug available for the management of acute hypertension, heart failure, and other vasoconstricted states as well as for the induction of controlled hypotension during surgery. It dilates both arteries and veins, has a rapid onset and offset of action, and is almost uniformly effective in achieving the desired degree of dilation by careful dosage titration. The need for close monitoring of its intravenous administration and the potential toxicity of prolonged infusions limit its general use from periods of hours to a few days, but its unique and usually well-maintained vascular actions make it an ideal agent for short-term therapy and a potentially useful model for development of new, orally effective vasodilator drugs.