Plasma concentrations and haemodynamic effects of nimodipine in patients resuscitated after cardiac arrest.

As the pharmacokinetics of a drug may be altered in haemodynamically compromised patients, the plasma concentrations and haemodynamic effects of the calcium entry blocker nimodipine have been examined in patients resuscitated after out-of-hospital cardiac arrest. In 7 patients nimodipine was infused at increasing rates up to 30 micrograms.kg-1.h-1. The plasma concentrations increased with increasing dose; at the highest dose a mean steady-state plasma concentration of 22.1 ng.ml-1 was obtained, and the mean plasma clearance was 1.41.kg-1.h-1. There were no marked changes in mean arterial blood pressure or heart rate. In 9 other patients nimodipine was given as a bolus infusion of 10 micrograms.kg-1 over 3 min, followed by a continuous infusion of 30 micrograms.kg-1.h-1. A mean steady-state plasma concentration of 17.6 ng.ml-1 was obtained and the mean plasma clearance was 1.91.kg-1.h-1. Heart rate did not change significantly, but the mean arterial blood pressure fell. The data indicate that in patients resuscitated after cardiac arrest, the pharmacokinetics of nimodipine are not markedly different from patients with other conditions, e.g. subarachnoid haemorrhage. However, if a loading dose is given to obtain a steady-state concentration sooner, there will be a fall in arterial blood pressure.