An experimental study of the effect of nimodipine in primate subarachnoid haemorrhage.

Acute subarachnoid haemorrhage was produced in baboons by a transorbital vessel avulsion technique. Half the animals were pretreated with an intravenous infusion of the calcium antagonistic nimodipine, in a dosage comparable with clinical levels. The severity of the haemorrhage, as measured by changes in intracranial pressure, cerebral perfusion pressure, cerebral blood flow and reactivity, and evoked potentials, was not greater in the group receiving nimodipine. Changes in extracellular K+ and pH were much less marked in animals receiving nimodipine. It is suggested that nimodipine (a) has a protective effect at a cellular level against the ionic changes of ischaemia, (b) does not alter the mechanical severity of subarachnoid haemorrhage.