Effects of intrathecal administration of nicardipine and nifedipine on chronic cerebral vasospasm in dogs.

Chronic cerebral vasospasm after subarachnoid haemorrhage (SAH) responds poorly to systemic administration of dihydropyridine calcium antagonists. However, the spastic arteries can be dilated by the topical (intrathecal) administration of the drugs. We examined by angiography the spasmolytic effects of intrathecal (cisternal) administration of nicardipine (0.1 mg 1 ml ) or nifedipine (0.1 mg 1 ml ) on day 7 of SAH made by the two-haemorrhage model in dogs. Both drugs dilated the spastic basilar artery from 15 min till 4 hours after the drug administration. The increase in the diameter of the basilar artery between 1 and 3 hours was statistically significant in both groups. Intrathecal administration of nicardipine which is water soluble, may be useful in the treatment of chronic cerebral vasospasm in patients.