A cerebral vasodilatory action could represent a critical adverse effect of any drug used to control the systemic blood pressure (SBP) in patients with an elevated intracranial pressure (ICP), since such an action increases the ICP and thereby reduces the cerebral perfusion pressure (CPP). While several new calcium antagonists are now available, each drug exerts variable dilatory actions on the cerebral, coronary and peripheral vasculatures. Among these agents, diltiazem has been found to be sufficiently potent to control systemic hypertension but to have a less potent dilatory action on the cerebral vasculature in experimental animals. Based on such a characteristic, diltiazem appears to be an ideal drug for controlling systemic hypertension in patients with an elevated ICP. However, little has yet been investigated in the clinical setting. In the present study, the effects of three drugs, i.e., nitroglycerin, nicardipine and diltiazem, on the ICP were analysed retrospectively. Data were collected from patients who had demonstrated a mildly elevated ICP (mean ICP, 10-23 mmHg) and moderate systemic hypertension (mean SBP, 97-125 mmHg) during the period of 72 hours after surgical evacuation of spontaneous intracerebral haematomas. We reviewed the computer-based records of 385 patients, and identified 35 episodes in which the mean SBP was reduced by more than 10 mmHg by one of these three drugs alone during the initial 24 hours after haematoma evacuation.(ABSTRACT TRUNCATED AT 250 WORDS)