Flunarizine, a calcium channel antagonist, is not neuroprotective when given after hypoxia-ischemia in the infant rat.

21-day-old rats were subjected to unilateral carotid ligation, then, after 2 h of recovery, to 2 h of 8% hypoxia. Immediately following the insult they were treated with either flunarizine (30 mg/kg, i.p.) or with an equal volume of diluent. We have previously shown similar doses of flunarizine to be neuroprotective when given preinsult. After 5 days they were sacrificed for histological analysis. Cerebral injury was almost entirely confined to the ligated side. Full-thickness cortical infarction was noted in 55% of controls (n = 29) versus 36% of flunarizine-treated rats (n = 28; p = 0.14). Mean damage scores for all areas assessed including cortex, striatum, and hippocampus were not significantly different. These observations suggest that flunarizine is not significantly neuroprotective when given immediately after severe hypoxia-ischemia.