Effects of antihypertensive drugs on intracranial hypertension

The effects of antihypertensive drugs, such as nifedipine, chlorpromazine, reserpine and thiopental on mean arterial blood pressure (ABP), mean intracranial pressure (ICP) and cerebral perfusion pressure (CPP) were studied in 43 patients with systemic hypertension and intracranial hypertension due to hemorrhagic cerebrovascular diseases and other causes. These drugs are commonly used in neurosurgical practice for the treatment of systemic hypertension. Nifedipine, chlorpromazine and reserpine reduced the mean ABP, raised the mean ICP and decreased the CPP. The effects of these drugs on mean ICP and CPP were more pronounced in patients with severely increased ICP (more than 40 mmHg) than in patients with moderately increased ICP (20-40 mmHg). Thiopental reduced both mean ABP and ICP, whereas the CPP was unchanged from the preadministration level. During thiopental administration, however, respiratory depression was observed, and hence, intubation and ventilation were required. We suggest that, in the treatment of systemic hypertension in patients with increased ICP, barbiturates are more desirable than agents with calcium channel or alpha-adrenergic blocking actions, despite the problem of respiratory control.