Nimodipine is a dihydropyridine calcium antagonist which has been shown to dilate cerebral arterioles and increase cerebral blood flow in animals and humans. It has potential in the treatment of a range of cerebrovascular disorders. Major interest to date, however, has focused on its use in the prevention and treatment of the delayed ischaemic neurological deficits that frequently occur in patients with subarachnoid haemorrhages as a result of sustained cerebral vasospasm. Nimodipine, a Ca2+ antagonist with cerebrovasodilatory and anti-ischemic effects, binds to rat, guinea pig, and human brain membranes with high affinity (less than 1 nM). Only at higher concentrations has nimodipine been reported to block the release of some neurotransmitters and hormones from neuronal tissue.