The efficacy of an abbreviated course of nimodipine in patients with good-grade aneurysmal subarachnoid hemorrhage

Nimodipine in Aneurysmal Subarachnoid Hemorrhage: Are Old Data Enough to Justify Its Current Treatment Regimen?

Nimodipine, a dihydropyridine L-type calcium channel antagonist, constitutes one of the mainstays of care to prevent delayed cerebral ischemia in patients with aneurysmal subarachnoid hemorrhage (aSAH) because it has been associated with a reduction in infarction rates and improvement in functional outcomes despite not significantly preventing angiographic vasospasm. Although it is a widely accepted treatment, controversies surrounding the current regimen of nimodipine in patients with aSAH exist. Still, there is a wide space open for randomized controlled trials or alternative study designs comparing different routes of administration, dosing, and timing of nimodipine treatment regimen in patients with aSAH.

Guidelines for the Neurocritical Care Management of Aneurysmal Subarachnoid Hemorrhage

BACKGROUND

The neurointensive care management of patients with aneurysmal subarachnoid hemorrhage (aSAH) is one of the most critical components contributing to short-term and long-term patient outcomes. Previous recommendations for the medical management of aSAH comprehensively summarized the evidence based on consensus conference held in 2011. In this report, we provide updated recommendations based on appraisal of the literature using the Grading of Recommendations Assessment, Development, and Evaluation methodology.

METHODS

The Population/Intervention/Comparator/Outcome (PICO) questions relevant to the medical management of aSAH were prioritized by consensus from the panel members. The panel used a custom-designed survey instrument to prioritize clinically relevant outcomes specific to each PICO question. To be included, the study design qualifying criteria were as follows: prospective randomized controlled trials (RCTs), prospective or retrospective observational studies, case-control studies, case series with a sample larger than 20 patients, meta-analyses, restricted to human study participants. Panel members first screened titles and abstracts, and subsequently full text review of selected reports. Data were abstracted in duplicate from reports meeting inclusion criteria. Panelists used the Grading of Recommendations Assessment, Development, and Evaluation Risk of Bias tool for assessment of RCTs and the "Risk of Bias In Nonrandomized Studies - of Interventions" tool for assessment of observational studies. The summary of the evidence for each PICO was presented to the full panel, and then the panel voted on the recommendations.

RESULTS

The initial search retrieved 15,107 unique publications, and 74 were included for data abstraction. Several RCTs were conducted to test pharmacological interventions, and we found that the quality of evidence for nonpharmacological questions was consistently poor. Five PICO questions were supported by strong recommendations, one PICO question was supported by conditional recommendations, and six PICO questions did not have sufficient evidence to provide a recommendation.

CONCLUSIONS

These guidelines provide recommendations for or against interventions proven to be effective, ineffective, or harmful in the medical management of patients with aSAH based on a rigorous review of the available literature. They also serve to highlight gaps in knowledge that should guide future research priorities. Despite improvements in the outcomes of patients with aSAH over time, many important clinical questions remain unanswered.

The role of nimodipine and magnesium sulfate in the prevention and treatment of vascular spasm in patients in the acute rupture of cerebral aneurysms

Vascular spasm in patients with hemorrhage from rupture of cerebral aneurysms is the main cause of adverse outcomes of the disease. One way to treat persistent contraction of cerebral arteries is to use nimodipine and magnesium sulfate. This literature review presents studies on the use of nimodipine and magnesium sulfate in the treatment of vascular spasm, and highlights the main links of pathogenesis and drug action mechanisms.

Impact of Early Versus Late Intravenous Followed by Oral Nimodipine Treatment on the Occurrence of Delayed Cerebral Ischemia Among Patients With Aneurysm Subarachnoid Hemorrhage

BACKGROUND

Guidelines for aneurysm subarachnoid hemorrhage (aSAH) management recommend treatment with nimodipine to all patients to reduce delayed cerebral ischemia (DCI) and poor clinical outcome. However, it did not give the most beneficial time to start therapy and route of administration.

OBJECTIVES

To compare the DCI occurrence and clinical outcome among aSAH patients who received nimodipine treatment at different times.

METHODS

A retrospective cohort study was conducted by collecting data from medical chart reviews between August 30, 2010, and October 31, 2015, at Prasart Neurological Institute, Thailand. Patients were classified into 2 groups by time to receive nimodipine: early group and late group (<96 and >96 hours, respectively). All patients received intravenous (IV) followed by oral nimodipine to complete treatment course. Clinical outcome was graded using the Glasgow Outcome Scale at 21 days. The factors related to DCI were analyzed using multivariate logistic regression.

RESULTS

A total of 149 patients were recruited: early (n = 97) and late (n = 52). No difference in baseline characteristics between groups was observed. The occurrence of DCI was not statistically significantly different between groups (early group, 18.60%, vs late group, 20.80%; P = 0.74). The World Federation of Neurosurgical Societies IV to V was associated with DCI occurrence. The proportion of patients with good outcome, poor outcome, or death did not show any difference between groups.

CONCLUSIONS AND RELEVANCE

Receiving IV nimodipine 3 to 7 days following oral therapy after bleeding can be the alternative regimen in patients who did not start nimodipine within 96 hours.

A Site-Specific, Sustained-Release Drug Delivery System for Aneurysmal Subarachnoid Hemorrhage

Nimodipine is the only drug approved for use by the Food and Drug Administration for improving outcome after aneurysmal subarachnoid hemorrhage (SAH). It has less than optimal efficacy, causes dose-limiting hypotension in a substantial proportion of patients, and is administered enterally 6 times daily. We describe development of site-specific, sustained-release nimodipine microparticles that can be delivered once directly into the subarachnoid space or cerebral ventricles for potential improvement in outcome of patients with aneurysmal SAH. Eight injectable microparticle formulations of nimodipine in poly(DL-lactide-co-glycolide) (PLGA) polymers of varying composition were tested in vitro, and 1 was advanced into preclinical studies and clinical application. Intracisternal or intraventricular injection of nimodipine-PLGA microparticles in rats and beagles demonstrated dose-dependent, sustained concentrations of nimodipine in plasma and cerebrospinal fluid for up to 29 days with minimal toxicity in the brain or systemic tissues at doses <2 mg in rats and 51 mg in beagles, which would be equivalent of up to 612-1200 mg in humans, based on scaling relative to cerebrospinal fluid volumes. Efficacy was tested in the double-hemorrhage dog model of SAH. Nimodipine-PLGA microparticles significantly attenuated angiographic vasospasm. This therapeutic approach shows promise for improving outcome after SAH and may have broader applicability for similar diseases that are confined to body cavities or spaces, are self-limited, and lack effective treatments.

Intrathecal application of the nimodipine slow-release microparticle system eg-1962 for prevention of delayed cerebral ischemia and improvement of outcome after aneurysmal subarachnoid hemorrhage

The effective reduction of delayed cerebral ischemia (DCI), a main contributor for poor outcome following aneurysmal subarachnoid hemorrhage (SAH), remains challenging. Previous clinical trials on systemic pharmaceutical treatment of SAH mostly failed to improve outcome, probably because of insensitive pharmaceutical targets and outcome measures, small sample size, insufficient subarachnoid drug concentrations and also detrimental, systemic effects of the experimental treatment per se. Interestingly, in studies that are more recent, intrathecal administration of nicardipine pellets following surgical aneurysm repair was suggested to have a beneficial effect on DCI and neurological outcome. However, this positive effect remained restricted to patients who were treated surgically for a ruptured aneurysm. Because of the favorable results of the preclinical data on DCI and neurological outcome in the absence of neurotoxicity or systemic side effects, we are initiating clinical trials. The PROMISE (Prolonged Release nimOdipine MIcro particles after Subarachnoid hemorrhage) trial is designed as an unblinded, nonrandomized, single-center, single-dose, dose-escalation safety and tolerability phase 1 study in patients surgically treated for aSAH and will investigate the effect of intracisternal EG-1962 administration. The NEWTON (Nimodipine microparticles to Enhance recovery While reducing TOxicity after subarachNoid hemorrhage) trial is a phase 1/2a multicenter, controlled, randomized, open-label, dose-escalation, safety, tolerability, and pharmacokinetic study comparing EG-1962 and nimodipine in patients with aneurysmal SAH.

Incidence of and factors associated with manipulation of nimodipine dosage in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

Aneurysmal subarachnoid hemorrhage is a significant cause of death and disability. Nimodipine 60 mg administered enterally every 4 h improves neurologic outcomes in these patients. However, hypotension is an adverse effect of nimodipine and is believed to prompt clinicians to prescribe an unproven, nonstandard nimodipine dosing regimen.

OBJECTIVES

The primary objective was to determine the prescribing incidence of a nonstandard nimodipine dosing regimen (30 mg every 2 h) after initial prescription of the standard dose (60 mg every 4 h). The secondary objective was to determine factors associated with this dosage change.

METHODS

This retrospective cohort study evaluated participants receiving nimodipine for aneurysmal subarachnoid hemorrhage at a tertiary care teaching hospital between October 2005 and December 2011. Univariate and multivariate regression analyses were performed to identify factors associated with dosage manipulation.

RESULTS

A total of 166 eligible patients were identified. For all of these patients, nimodipine 60 mg every 4 h was prescribed initially. Subsequently, 81 (49%) of the patients were switched to nimodipine 30 mg every 2 h, whereas 85 (51%) continued on the original dosage (nimodipine 60 mg every 4 h) for the duration of their treatment. Multivariate analysis revealed that occurrence of vasospasm (odds ratio [OR] 5.30, 95% confidence interval [CI] 2.08-13.47; p < 0.001) and exposure to vasopressor therapy (OR 3.29, 95% CI 1.27-8.50; p = 0.014) were associated with increased odds of receiving the nonstandard nimodipine regimen.

CONCLUSIONS

Half of patients for whom nimodipine was prescribed for aneurysmal subarachnoid hemorrhage were exposed to an unproven regimen. Vasospasm and exposure to vasopressor therapy were associated with higher odds of receiving the nonstandard regimen. Further research is needed to evaluate whether nimodipine 30 mg every 2 h is efficacious and safe for patients in this population.

Preparation, Characterization, and Pharmacokinetics of Sterically Stabilized Nimodipine-Containing Liposomes

Nimodipine is a dihydropyridine calcium antagonist used in clinical trials in the treatment of ischemic damage in subarachnoid hemorrhage and commercially available as nimotop intravenous infusion solution and tablets. However, due to its poor solubility in water, intravenous administration depends on the use of the dehydrated alcohol to achieve a clinically relevant concentrated infusion solution while the low bioavailability of the nimotop tablets were far away from content. We have prepared a well-characterized novel lyophilized liposome-based nimodipine formulation that is sterile and easy-to-use. Of the several formulations examined, nimodipine-liposomes composed of ePC/CHOL 20:3 and co-surfactant poloxamer 188/sodium deoxycholate/ePC/3:0.3:5 were chosen for further studies. This composition was found to give more stable liposomes than other formulations. It gave 89.9% entrapment efficiency and particle size of 200 nm after lyophilization. The pharmacokinetic parameters following orally and intravenously administration to New Zealand rabbits were determined and compared with those of commercial nimodipine formulations. Encapsulation of nimodipine in liposomes produced marked differences over those of commercial preparations with an increased C(max), prolonged elimination half-life, and an increased value for AUC. The obtained values for mean residence time (MRT) indicated that nimodipine remains longer for liposomal formulation. Thus an optimum i.v. liposome formulation for nimodipine can be developed for an alternative to the commercial nimodipine preparations.

Management of cerebral vasospasm

Cerebral vasospasm is delayed narrowing of the large arteries of the circle of Willis occurring 4 to 14 days after aneurysmal subarachnoid hemorrhage (SAH). It is but one cause of delayed deterioration after SAH but, in general, is the most important potentially treatable cause of morbidity and mortality after SAH. Development of vasospasm is best predicted by the volume, location, persistence and density of subarachnoid clot early after SAH. Diagnosis is made by catheter angiography or, with less accuracy, by computed tomographic angiography, transcranial Doppler ultrasound or other methods. Treatment remains problematic because it is expensive, time-consuming, associated with substantial risk and largely ineffective. Treatment includes optimization of factors that affect cerebral blood flow and metabolism, systemic administration of nimodipine, hemodynamic therapy and pharmacologic and mechanical angioplasty.

Subcutaneous administration of nimodipine improves bioavailability in rabbits

We compared subcutaneous and oral methods of nimodipine administration to determine a method of nimodipine administration that maintained serum levels at or above the optimal therapeutic concentration (7 ng/ml). Plasma concentrations of nimodipine were measured in New Zealand White rabbits (2.6-3.9 kg). First, peak plasma concentration (C(max)), time to reach peak plasma concentration (T(max)), and area under the curve (AUC) parameters were calculated and compared between animals receiving oral or subcutaneous nimodipine (5-15 mg/kg). Next, plasma concentrations were measured 24 h after subcutaneous administration of 2.5 mg/kg of nimodipine in healthy animals and animals with experimentally induced SAH. C(max), T(max) and AUC parameters were significantly greater for subcutaneous compared to oral nimodipine administration, irrespective of dose. Mean nimodipine concentrations at 24 h were >7 ng/ml in both healthy animals (12.9 +/- 10.0 ng/ml) and in animals with SAH (11.8 +/- 4.6 ng/ml) that received 2.5 mg/kg of subcutaneous nimodipine. In this model, the subcutaneous method of nimodipine administration consistently maintains plasma levels at or above the optimal therapeutic concentration, whereas oral administration fails to do so.

Clinical outcomes of aneurysmal subarachnoid hemorrhage patients treated with oral diltiazem and limited intensive care management

BACKGROUND

Aneurysmal subarachnoid hemorrhage (SAH) patients are frequently treated with prophylactic nimodipine and undergo invasive monitoring of blood pressure and volume status in an intensive care unit (ICU) setting to decrease the incidence of delayed ischemic neurological deficit (DIND) and improve functional outcomes. The goal of this study was to examine the incidence of DIND and poor functional outcomes in a consecutive series of SAH patients treated with a different regimen of prophylactic oral diltiazem and limited use of intensive care monitoring.

METHODS

The study involved a consecutive series of 123 aneurysmal SAH patients treated by the senior author who were admitted within 72 hours of hemorrhage and who never received nimodipine or nicardipine. Functional outcomes were graded using the Glasgow Outcome Scale (GOS).

RESULTS

Of the 123 patients identified, favorable outcomes (GOS 4 and 5) were achieved in 74.8%. The incidence of DIND was 19.5%. Hypertensive, hypervolemic, hemodilutional (HHH) therapy was used in 10 patients (8.1%) and no patients were treated for DIND by endovascular means. Seven patients (5.7%) had a poor functional outcome or death because of DIND and two of these were related to complications of HHH therapy. These results were compared to contemporary series of SAH patients managed with other treatment protocols.

CONCLUSIONS

Functional outcomes of patients treated with a regimen of oral diltiazem, limited use of ICU monitoring and HHH therapy for DIND compare favorably with other contemporary series of SAH patients.