Drug therapy in brain ischaemia.

After many years of research, drug treatment in cerebral hypoxia is still controversial and no treatment appears to be firmly established. Not even the mechanisms causing damage have been established (Siesjo, 1981), only that they are linked to a disturbance in the oxygen demand: supply ratio. Enthusiasm for new modes of therapy have waxed and waned. We have witnessed alternating enthusiasm for cerebral vasodilators, cerebral vasoconstrictors, cerebral metabolic depressants, free radical scavengers, membrane stabilizers, calcium blockers, drugs that improve blood rheology, and drugs that are reported simply to improve cerebral function in a "black box" fashion. Part of the apparent conflicts in the literature may result from great variety in the models used to test pharmacological brain protection. To clarify some of the confusion it is important to differentiate between species, preand post-treatment and the main categories of cerebral hypoxia (table I).