Nimodipine treatment of subarachnoid hemorrhage

Cerebrospinal Fluid Concentrations of Nimodipine Correlate With Long-term Outcome in Aneurysmal Subarachnoid Hemorrhage: Pilot Study

OBJECTIVES

The aim was to evaluate plasma and cerebrospinal fluid (CSF) nimodipine concentrations in patients with aneurysmal subarachnoid hemorrhage and their correlation with clinical outcome.

METHODS

Nimodipine infusion was started at 1 mg/h and increased up to 2 mg/h and continued up to 21 days in surviving patients. Arterial and CSF samples were collected at least after 24 hours of stable nimodipine dosing. Delayed cerebral ischemia and vasospasm were documented by new neurological deficits and neuroimaging. The clinical outcome was assessed at 9 months by the modified Rankin scale.

RESULTS

Twenty-three patients were enrolled. Nimodipine dose was 13 to 38 μg/kg per hour. Nimodipine arterial and CSF concentrations were 24.9 to 71.8 ng/mL and 37 to 530 pg/mL, respectively. Dose did not correlate with arterial or CSF concentrations. Arterial concentrations did not correlate with corresponding CSF concentrations. Doses and arterial concentrations did not correlate with the clinical outcome and were not associated with the occurrence of delayed cerebral ischemia. However, patients with no significant disability after 9 months of hemorrhage showed significantly higher CSF nimodipine concentrations (P = 0.015) and CSF-to-plasma ratios (P = 0.011) compared with patients who showed some degree of disability or who died.

CONCLUSIONS

Cerebrospinal fluid nimodipine concentrations measured during hospital drug infusion showed a correlation with long-term clinical outcome in patients with aneurysmal subarachnoid hemorrhage. These very preliminary data suggest that CSF concentrations monitoring may have some value in managing these patients.

Nimodipine pharmacokinetics after intraventricular injection of sustained-release nimodipine for subarachnoid hemorrhage

OBJECTIVE

The objective of this study was to measure the concentration of nimodipine in CSF and plasma after intraventricular injection of a sustained-release formulation of nimodipine (EG-1962) in patients with aneurysmal subarachnoid hemorrhage (SAH).

METHODS

Patients with SAH repaired by clip placement or coil embolization were randomized to EG-1962 or oral nimodipine. Patients were classified as grade 2-4 on the World Federation of Neurosurgical Societies grading scale for SAH and had an external ventricular drain inserted as part of their standard of care. Cohorts of 12 patients received 100-1200 mg of EG-1962 as a single intraventricular injection (9 per cohort) or they remained on oral nimodipine (3 per cohort). Plasma and CSF were collected from each patient for measurement of nimodipine concentrations and calculation of maximum plasma and CSF concentration, area under the concentration-time curve from day 0 to 14, and steady-state concentration.

RESULTS

Fifty-four patients in North America were randomized to EG-1962 and 18 to oral nimodipine. Plasma concentrations increased with escalating doses of EG-1962, remained stable for 14 to 21 days, and were detectable at day 30. Plasma concentrations in the oral nimodipine group were more variable than for EG-1962 and were approximately equal to those occurring at the EG-1962 800-mg dose. CSF concentrations of nimodipine in the EG-1962 groups were 2-3 orders of magnitude higher than in the oral nimodipine group, in which nimodipine was only detected at low concentrations in 10% (21/213) of samples. In the EG-1962 groups, CSF nimodipine concentrations were 1000 times higher than plasma concentrations.

CONCLUSIONS

Plasma concentrations of nimodipine similar to those achieved with oral nimodipine and lasting for 21 days could be achieved after a single intraventricular injection of EG-1962. The CSF concentrations from EG-1962, however, were at least 2 orders of magnitude higher than those with oral nimodipine. These results supported a phase 3 study that demonstrated a favorable safety profile for EG-1962 but yielded inconclusive efficacy results due to notable differences in clinical outcome based on baseline disease severity.Clinical trial registration no.: NCT01893190 (ClinicalTrials.gov).

Acute effects of intraventricular nicardipine on cerebral hemodynamics: A preliminary finding

OBJECTIVE

Intraventricular nicardipine (IVTN) is a treatment option for severe vasospasm in patients with subarachnoid hemorrhage (SAH). However, its acute effects on cerebral hemodynamics have not been studied in detail.

METHODS

Between June 2008 and December 2010, IVTN was administered (mainly 4mg every 8h) to 11 SAH patients (54 doses) with multimodality monitoring for refractory vasospasm. Retrospective analyses on physiological parameters were made from baseline and up to 6h after IVTN injection. Statistical analysis was performed with a mixed-effects model.

RESULTS

Mean intracranial pressure (ICP) increased slightly, reaching its peak at 20min after IVTN injection (2.5±0.9mmHg (mean±standard error), P<0.01), and decreased gradually thereafter over the next hour. Mean cerebral perfusion pressure transiently decreased 20-30min after injection (3.7±1.8mmHg, P<0.05). Mean arterial pressure, partial pressure of brain oxygen tension (PbtO2), cerebral blood flow (CBF), autoregulation indices did not change significantly. Lactate/pyruvate ratio and glucose remained stable. One patient underwent transcranial Doppler ultrasonography monitoring while on IVTN, which showed a transient increase in mean flow velocity with concomitant decrease in Pulsatility index, suggesting vasodilation in the distal resistance vessels.

CONCLUSIONS

The vasodilatory effect of IVTN transiently increased ICP, but did not significantly affect PbtO2, CBF or oxidative glucose metabolism in the immediate phase after injection.

Intracranial biodegradable silica-based nimodipine drug release implant for treating vasospasm in subarachnoid hemorrhage in an experimental healthy pig and dog model

Nimodipine is a widely used medication for treating delayed cerebral ischemia (DCI) after subarachnoid hemorrhage. When administrated orally or intravenously, systemic hypotension is an undesirable side effect. Intracranial subarachnoid delivery of nimodipine during aneurysm clipping may be more efficient way of preventing vasospasm and DCI due to higher concentration of nimodipine in cerebrospinal fluid (CSF). The risk of systemic hypotension may also be decreased with intracranial delivery. We used animal models to evaluate the feasibility of surgically implanting a silica-based nimodipine releasing implant into the subarachnoid space through a frontotemporal craniotomy. Concentrations of released nimodipine were measured from plasma samples and CSF samples. Implant degradation was followed using CT imaging. After completing the recovery period, full histological examination was performed on the brain and meninges. The in vitro characteristics of the implant were determined. Our results show that the biodegradable silica-based implant can be used for an intracranial drug delivery system and no major histopathological foreign body reactions were observed. CT imaging is a feasible method for determining the degradation of silica implants in vivo. The sustained release profiles of nimodipine in CSF were achieved. Compared to a traditional treatment, higher nimodipine CSF/plasma ratios can be obtained with the implant.

Nimodipine activates TrkB neurotrophin receptors and induces neuroplastic and neuroprotective signaling events in the mouse hippocampus and prefrontal cortex

The L-type calcium channel blocker nimodipine improves clinical outcome produced by delayed cortical ischemia or vasospasm associated with subarachnoid hemorrhage. While vasoactive mechanisms are strongly implicated in these therapeutic actions of nimodipine, we sought to test whether nimodipine might also regulate neurotrophic and neuroplastic signaling events associated with TrkB neurotrophin receptor activation. Adult male mice were acutely treated with vehicle or nimodipine (10 mg/kg, s.c., 1.5 h) after which the phosphorylation states of TrkB, cyclic-AMP response element binding protein (CREB), protein kinase B (Akt), extracellular regulated kinase (ERK), mammalian target of rapamycin (mTor) and p70S6 kinase (p70S6k) from prefrontal cortex and hippocampus were assessed. Nimodipine increased the phosphorylation of the TrkB catalytic domain and the phosphoslipase-Cγ1 (PLCγ1) domain, whereas phosphorylation of the TrkB Shc binding site remained unaltered. Nimodipine-induced TrkB phosphorylation was associated with increased phosphorylation levels of Akt and CREB in the prefrontal cortex and the hippocampus whereas phosphorylation of ERK, mTor and p70S6k remained unaltered. Nimodipine-induced TrkB signaling was not associated with changes in BDNF mRNA or protein levels. These nimodipine-induced changes on TrkB signaling mimic those produced by antidepressant drugs and thus propose common mechanisms and long-term functional consequences for the effects of these medications. This work provides a strong basis for investigating the role of TrkB-associated signaling underlying the neuroprotective and neuroplastic effects of nimodipine in translationally relevant animal models of brain trauma or compromised synaptic plasticity.

Intracranial drug delivery for subarachnoid hemorrhage

Tice and colleagues pioneered site-specific, sustained-release drug delivery to the brain almost 30 years ago. Currently there is one drug approved for use in this manner. Clinical trials in subarachnoid hemorrhage have led to approval of nimodipine for oral and intravenous use, but other drugs, such as clazosentan, hydroxymethylglutaryl CoA reductase inhibitors (statins) and magnesium, have not shown consistent clinical efficacy. We propose that intracranial delivery of drugs such as nimodipine, formulated in sustained-release preparations, are good candidates for improving outcome after subarachnoid hemorrhage because they can be administered to patients that are already undergoing surgery and who have a self-limited condition from which full recovery is possible.

Studies on concentration-time profiles of nimodipine enantiomers following intravenous and oral administration of nimodipine in patients with subarachnoid hemorrhage

After i.v. and oral administration of nimodipine the concentration-time profiles of the drug and its enantiomers were studied in seven patients with subarachnoid hemorrhage. Concentrations of nimodipine, (+)-(R)-, and (-)-(S)-nimodipine were analyzed using a new stereoselective high-performance liquid chromatographic method. During the first 3 h after oral administration the concentrations of (+)-(R)- and (-)-(S)-nimodipine were significantly different, the (-)-(S)-enantiomer being found in much lesser concentrations compared to the (+)-(R)-enantiomer. The results indicate that if uptake from the gastrointestinal system is equal for the two enantiomers, then (-)-(S)-nimodipine is metabolized at a much faster rate compared to (+)-(R)-nimodipine after oral administration of the drug in patients with subarachnoid bleeding. After i.v. administration; no significant differences between the concentrations of the (-)-(S) and the (+)-(R) isomers were demonstrated.

A multicenter trial of the efficacy of nimodipine on outcome after severe head injury. The European Study Group on Nimodipine in Severe Head Injury

Between January 1, 1989, and June 30, 1991, 852 severely head-injured patients were entered into a prospective placebo-controlled trial of the efficacy of nimodipine administration. The patients could not obey commands at the time of entry into the trial, which was within 12 hours after the start of the inability to obey commands and within 24 hours of injury. The main hypothesis that nimodipine would increase the percentage of patients with a favorable outcome (moderate disability or good recovery) from 50% to 60% was rejected. A trend toward a favorable effect was seen in patients who exhibited traumatic subarachnoid hemorrhage (SAH) on the computerized tomography (CT) scan obtained prior to entry into the study. The effect was statistically significant in those patients who complied with all protocol requirements. This finding is consistent with the effect of nimodipine on secondary ischemia following spontaneous SAH. The results of the study warrant a clinical trial of the efficacy of nimodipine in severely head-injured patients who show traumatic SAH on the initial CT scan.