Arterial hypertension and/or tachycardia may alter intracranial pressure in neurosurgical patients. We compared the effects of pancuronium 0.1 mg/kg and pipecuronium 0.1 mg/kg given as i.v. bolus on cerebrospinal fluid (CSF) pressure in 2 groups of 10 patients each scheduled for intracranial surgery in the supine position. Before surgery, no patient presented clinical symptoms of elevated intracranial pressure (ICP). Anesthesia was induced and maintained with fentanyl and midazolam. Ventilation with 50% nitrous oxide in oxygen was adjusted to maintain arterial pCO2 at 30-35 mmHg. After induction of anesthesia, CSF pressure was registered via a lumbar subarachnoid catheter before and 3, 5, 10, and 30 min after pipecuronium or pancuronium administration. Hemodynamics were monitored using radial and pulmonary artery catheters. All variables underwent analyses of variance for repeated measures with p < 0.05 considered significant. Mean CSF pressure decreased insignificantly from 15 +/- 5 mmHg (before injection) to 14 +/- 4 mmHg in patients given pipecuronium and from 13 +/- 4 mmHg to 10 +/- 3 mmHg in the pancuronium group without significant differences between the study groups. Heart rate and arterial pressure increased significantly (p < 0.001) in patients given pancuronium but remained stable after pipecuronium. Onset and duration of neuromuscular blockade were comparable between groups. Based on our results, pipecuronium is a safe alternative to pancuronium during neurosurgical procedures in patients without abnormally high intracranial pressure.