Nimodipine. Potential for drug-drug interactions in the elderly

Beyond nimodipine: advanced neuroprotection strategies for aneurysmal subarachnoid hemorrhage vasospasm and delayed cerebral ischemia

The clinical management of aneurysmal subarachnoid hemorrhage (SAH)-associated vasospasm remains a challenge in neurosurgical practice, with its prevention and treatment having a major impact on neurological outcome. While considered a mainstay, nimodipine is burdened by some non-negligible limitations that make it still a suboptimal candidate of pharmacotherapy for SAH. This narrative review aims to provide an update on the pharmacodynamics, pharmacokinetics, overall evidence, and strength of recommendation of nimodipine alternative drugs for aneurysmal SAH-associated vasospasm and delayed cerebral ischemia. A PRISMA literature search was performed in the PubMed/Medline, Web of Science, ClinicalTrials.gov, and PubChem databases using a combination of the MeSH terms "medical therapy," "management," "cerebral vasospasm," "subarachnoid hemorrhage," and "delayed cerebral ischemia." Collected articles were reviewed for typology and relevance prior to final inclusion. A total of 346 articles were initially collected. The identification, screening, eligibility, and inclusion process resulted in the selection of 59 studies. Nicardipine and cilostazol, which have longer half-lives than nimodipine, had robust evidence of efficacy and safety. Eicosapentaenoic acid, dapsone and clazosentan showed a good balance between effectiveness and favorable pharmacokinetics. Combinations between different drug classes have been studied to a very limited extent. Nicardipine, cilostazol, Rho-kinase inhibitors, and clazosentan proved their better pharmacokinetic profiles compared with nimodipine without prejudice with effective and safe neuroprotective role. However, the number of trials conducted is significantly lower than for nimodipine. Aneurysmal SAH-associated vasospasm remains an area of ongoing preclinical and clinical research where the search for new drugs or associations is critical.

Nimodipine-associated standard dose reductions and neurologic outcomes after aneurysmal subarachnoid hemorrhage: the era of pharmacogenomics

Nimodipine, an L-type cerebroselective calcium channel antagonist, is the only drug approved by the US Food and Drug Administration for the neuroprotection of patients with aneurysmal subarachnoid hemorrhage (aSAH). Four randomized, placebo-controlled trials of nimodipine demonstrated clinical improvement over placebo; however, these occurred before precision medicine with pharmacogenomics was readily available. The standard enteral dose of nimodipine recommended after aSAH is 60 mg every 4 h. However, up to 78% of patients with aSAH develop systemic arterial hypotension after taking the drug at the recommended dose, which could theoretically limit its neuroprotective role and worsen cerebral perfusion pressure and cerebral blood flow, particularly when concomitant vasospasm is present. We investigated the association between nimodipine dose changes and clinical outcomes in a consecutive series of 150 patients (mean age, 56 years; 70.7% women) with acute aSAH. We describe the pharmacogenomic relationship of nimodipine dose reduction with clinical outcomes. These results have major implications for future individualized dosing of nimodipine in the era of precision medicine.

Nimodipine Pharmacokinetic Variability in Various Patient Populations

Nimodipine has been shown to improve outcomes following aneurysmal subarachnoid hemorrhage. Guidelines recommend that all patients receive a fixed dose of oral nimodipine for 21 days. However, pharmacokinetic studies have suggested variability of nimodipine pharmacokinetics in subarachnoid hemorrhage and in other patient populations. The clinical relevance of such variability is unknown. Therefore, the objective of the present review is, first, to conduct a literature review and summarize nimodipine pharmacokinetic data and sources of variability in various patient groups. Second, to determine if there is any evidence reporting an association between nimodipine exposure and clinical outcomes in patients with subarachnoid hemorrhage. A systematic literature search was performed in MEDLINE and EMBASE. The following keywords were used: ("nimodipine" OR "nymalize" OR "nimotop") AND ("pharmacokinetic*", OR "PK"). The search results were limited to English language and human studies. A large interpatient variability in nimodipine pharmacokinetics has been reported. Patient-specific factors that had an influence on pharmacokinetic parameters are age, comorbidities, variabilities in metabolism due to genetic polymorphism and co-administered medications, as well as nimodipine administration technique. The association between nimodipine exposure and clinical outcomes remains unclear and data available are too scarce to reach a firm conclusion. Here, we present a narrative review with a systematic literature search discussing nimodipine pharmacokinetic variability in various patient populations. It is not clear if minimal or lack of systemic exposure to nimodipine denies its benefit and contributes to worsening outcomes in patients with subarachnoid hemorrhage. Further studies are needed to determine if such an association exists.

Alcohol Withdrawal Syndrome in Neurocritical Care Unit: Assessment and Treatment Challenges

Alcohol withdrawal syndrome (AWS) can range from mild jittery movements, nausea, sweating to more severe symptoms such as seizure and death. Severe AWS can worsen cognitive function, increase hospital length of stay, and in-hospital mortality and morbidity. Due to a lack of reliable history of present illness in many patients with neurological injury as well as similarities in clinical presentation of AWS and some commonly encountered neurological syndromes, the true incidence of AWS in neurocritical care patients remains unknown. This review discusses challenges in the assessment and treatment of AWS in patients with neurological injury, including the utility of different scoring systems such as the Clinical Institute Withdrawal Assessment and the Minnesota Detoxification Scale as well as the reliability of admission alcohol levels in predicting AWS. Treatment strategies such as symptom-based versus fixed dose benzodiazepine therapy and alternative agents such as baclofen, carbamazepine, dexmedetomidine, gabapentin, phenobarbital, ketamine, propofol, and valproic acid are also discussed. Finally, a treatment algorithm considering the neurocritical care patient is proposed to help guide therapy in this setting.

Nimodipine-induced junctional bradycardia in an elderly patient with subarachnoid hemorrhage

Subarachnoid hemorrhage is a devastating form of stroke with often detrimental outcomes for patients. Here we describe a patient with subarachnoid hemorrhage treated with nimodipine, which resulted in marked bradycardia with junctional atrioventricular heart block. Nimodipine is metabolized predominantly by the cytochrome P450 3A subfamily, and its use is often associated with adverse events, such as hypotension and bradycardia, which can be exacerbated by advanced age. Our patient had the CYP3A5*3/*3 genotype, possibly predisposing her to poor metabolism of this drug. Our case report demonstrates the potential for pharmacogenomics in patients with subarachnoid hemorrhage to help predict their response to nimodipine, minimize adverse drug reactions, and potentially individualize dosing to improve future clinical outcomes.

Pharmacogenomics of Cytochrome P450 of Nimodipine Metabolism After Aneurysmal Subarachnoid Hemorrhage

INTRODUCTION

Aneurysmal subarachnoid hemorrhage (aSAH) is a type of stroke that is life threatening with high rates of mortality, and many survivors are left with permanent neurologic deficits. Nimodipine is the treatment of choice for aSAH with the goal of reduction of delayed cerebral ischemia. It is the only evidence-based medication that has been shown to have improved outcomes for delayed cerebral ischemia; therefore, it is important for neuroscience nurses to be knowledgeable of the pharmacology and pharmacogenomics properties of this medication, including cytochrome P450 (CYP450) enzymes.

METHODS AND RESULTS

This article reviews the CYP450 enzyme system including a review of the pharmacotherapy and pharmacogenomics of nimodipine for patients with aSAH illustrated with case study of a patient with abnormal drug metabolism.

CONCLUSION

CYP450 enzymes can be inhibited or induced by multiple medications resulting in clinically significant differences in drug metabolism. Food and Drug Administration-approved medication nimodipine is the only medication shown to improve outcomes in patients with aSAH. Hence, it is important to have awareness of potential drug-to-drug interactions and pharmacogenomics of nimodipine when caring for critically ill patients with aSAH.

1,4-Dihydropyridine: A Dependable Heterocyclic Ring with the Promising and the Most Anticipable Therapeutic Effects

:

Nowadays, heterocyclic compounds act as a scaffold and are the backbone of medicinal chemistry. Among all of the heterocyclic scaffolds, 1,4-Dihydropyridine (1,4-DHP) is one of the most important heterocyclic rings that possess prominent therapeutic effects in a very versatile manner and plays an important role in synthetic, medicinal, and bioorganic chemistry. The main aim of the study is to review and encompass relevant studies related to 1,4-DHP and excellent therapeutic benefits of its derivatives. An extensive review of Pubmed-Medline, Embase and Lancet’s published articles was done to find all relevant studies on the activity of 1,4-DHP and its derivatives. 1,4-DHP is a potent Voltage-Gated Calcium Channel (VGCC) antagonist derivative which acts as an anti-hypertensive, anti- anginal, anti-tumor, anti-inflammatory, anti-tubercular, anti-cancer, anti-hyperplasia, anti-mutagenic, anti-dyslipidemic, and anti-ulcer agent. From the inferences of the study, it can be concluded that the basic nucleus, 1,4-DHP which is a voltage-gated calcium ion channel blocker, acts as a base for its derivatives that possess different important therapeutic effects. There is a need of further research of this basic nucleus as it is a multifunctional moiety, on which addition of different groups can yield a better drug for its other activities such as anti-convulsant, anti-oxidant, anti-mutagenic, and anti-microbial. This review would be significant for further researches in the development of several kinds of drugs by representing successful matrix for the medicinal agents.

Serum levels of nimodipine in enteral and parenteral administration in patients with aneurysmal subarachnoid hemorrhage

BACKGROUND

The aim of this study was to evaluate serum nimodipine concentrations in patients with aneurysmal subarachnoid hemorrhage (SAH) after parenteral therapy and a following course of enteral administration.

METHODS

SAH patients were treated with intravenous nimodipine (2 mg/h) during the 1st week after hemorrhage, and on day 8, we switched over to enteral administration (60 mg/4 h), either orally or by gavage. Serum nimodipine concentrations were measured on days 3, 5, 8, 9 and 12. Area under the curve (AUC) was calculated during parenteral and enteral therapy. The data of 15 patients were analyzed retrospectively.

RESULTS

In this study, 157 blood samples were obtained. In seven samples, during the administration by gavage to two patients with high-grade SAH, the serum nimodipine concentrations were negligible. The AUC values during parenteral administration (median 149.3 ng-h/ml) were significantly higher than during oral administration on days 9 (median 92.1 ng-h/ml) and 12 (median 44.1 ng-h/ml) in seven patients (p = 0.030 and p = 0.016, respectively). The AUC values during parenteral administration were significantly higher than during administration by gavage on day 9 in eight patients (median 87.9 and 34 ng-h/ml, respectively, p = 0.001). The AUC values during enteral administration were higher in patients who received nimodine orally than in those who received it by gavage (median 52.3 and 23.1 ng-h/ml, respectively, p = 0.006).

CONCLUSIONS

Enteral administration of nimodipine showed lower bioavailability during the 2nd week after SAH compared to parenteral application during the 1st week. Negligible serum concentrations were even expected when nimodipine was given by gavage in patients with high-grade SAH, thus suggesting that parenteral administration may be the better route in these patients.

Early-phase pharmacokinetics of enteral and parenteral nimodipine in patients with acute subarachnoid haemorrhage - a pilot study

OBJECTIVE

The pharmacokinetics of nimodipine following enteral administration in the early phase after subarachnoid haemorrhage (SAH) has not been described. If a sufficient absorption could be achieved with enterally administered nimodipine, this would be more feasible dosage form and result in a significant reduction in pharmaceutical costs given that the parenteral formulation of nimodipine currently used is tenfold more expensive than the enteral formulation.

METHODS

This was a pilot study in which 17 patients with aneurysmal SAH were randomly assigned to receive nimodipine within 24 h after initial bleeding either as an 60 mg tablet/suspension at 4-h intervals, or as a continuous intravenous infusion of 2 mg/h. Serum nimodipine concentrations were measured during the 4 h following the first dose, and at 24 and 72 h on a validated gas chromatography mass spectrometer (GC-MS).

RESULTS

Nimodipine AUC values (expressed in mug min/ml) were lower in the eight SAH patients receiving enteral nimodipine [AUC(0-4) range: 0.13-5.4 (median: 0.32); AUC(24-28) range: 0.16-6.1 (0.71); AUC(72-76) range: 0.47-20.6 (1.9)] than in the nine patients receiving a continuous intravenous infusion of nimodipine [AUC(0-4) range: 2.4-4.9 (3.4), p=0.059; AUC(24-28) range: 4.7-10.3 (7.3), p=0.001; AUC(72-76) range: 3.4-8.6 (6.9), p=0.001]. In three of five good-grade SAH patients receiving nimodipine tablets the AUC values were comparable to those of the intravenous administration, but in two good-grade patients with tablets and in all three poor-grade (Hunt&Hess, grade IV) SAH patients receiving the suspension, the rate and extent of nimodipine absorption was negligible.

CONCLUSION

This pilot study indicates that the rate and extent of nimodipine absorption following enteral administration in some acute SAH patients could be negligible, and this may particularly be the case in patients with a decreased level of consciousness.

Analytical study of photodegradation of inclusion complexes of nimodipine with alpha-, gamma-cyclodextrin, methyl-beta-cyclodextrin, and hydroxypropyl-beta-Cyclodextrin

The inclusion behavior of alpha-cyclodextrin (alpha-CD), gamma-cyclodextrin (gamma-CD), hydroxypropyl-beta-cyclodextrin (HP-betaCD), and methyl-beta-cyclodextrin (M-betaCD) with nimodipine (NM) in solution and in the solid state was investigated. Inclusion complexes of nimodipine with cyclodextrins (at a molar ratio of 1:1) in the solid state were obtained by the kneading method. Photochemical stability of NM in the solid inclusion complexes was assessed by IR spectrometry. The modified derivatives of beta-CD and alpha-CD were found to slow the photodegradation rate, whereas in the presence of gamma-CD the photodegradation of NM was a bit faster than in the corresponding physical mixture. Photochemical degradation of NM in liquid inclusion complexes was monitored by UV spectroscopy. According to the slowing effect on photodegradation of NM in the inclusion complexes, the studied cyclodextrins can be ordered as gamma-CD < alpha-CD < HP-betaCD < M-betaCD.

Severe serotonin syndrome induced by mirtazapine monotherapy

OBJECTIVE

To document a case of serotonin syndrome (SS) associated with mirtazapine monotherapy, review the previously reported cases of SS associated with this tetracyclic antidepressant, and discuss the possible pathogenic mechanisms leading to this serious adverse drug reaction.

CASE SUMMARY

A 75-year-old man developed agitation, confusion, incoordination, and gait disturbance because of progressive rigidity. Mirtazapine had been started 8 days earlier to control major depression. Physical examination revealed diaphoresis, low-grade fever, hypertension, tachycardia, bilateral cogwheel rigidity, hyperreflexia, tremor, and myoclonus, symptoms and signs that are consistent with severe SS.

DISCUSSION

A review of the cases of SS with implication of mirtazapine as the cause was performed. The possible pathogenic mechanisms leading to this adverse reaction in this patient are also discussed, and pathophysiologic hypotheses are formulated.

CONCLUSIONS

Although mirtazapine offers clinicians a combination of strong efficacy and good safety, we suggest bearing SS in mind when prescribing this drug, especially in frail, elderly patients with underlying chronic conditions. In these patients, it might be more adequate to start mirtazapine therapy at a lower dose (<15 mg/d).