Common carotid haemodynamic and metabolic effects of acutely administered nifedipine in human subarachnoid haemorrhage

Abstract
Although the drugs known as “calcium antagonists” exert inhibitory actions on vascular smooth muscle, there are no quantitative data concerning the clinical use of these vasodilator agents in human subarachnoid haemorrhage. In the present clinical study, we have measured the effects of nifedipine (20 mg tablet) on common carotid artery diameter (D) blood flow velocity (V) common carotid blood flow (CCBF) as an index of cerebral blood flow, systolic (Qs) and diastolic (Qd) blood flow fractions using a pulsed Doppler apparatus and on carotid arterial pressure (CAP), heart rate (HR) and oxygen consumption (V̇O2). Eight patients with subarachnoid haemorrhage were studied during anaesthesia for cerebral angiography. Thirty minutes after sublingual nifedipine, diameter (Pin vivo, nifedipine exerts a preferential action on cerebral vessels, vasodilating large arteries and arterioles. This action is more powerful if the vessels are already vasoconstricted. Thus, the use of nifedipine could be fruitful in cerebral ischaemia that is secondary to subarachnoid haemorrhage.