D2 receptor blockade by flunarizine and cinnarizine explains extrapyramidal side effects. A SPECT study

Prophylactic treatments for vestibular migraine: a systematic review and network meta-analysis of randomized clinical trials

Objectives: We compared and ranked the efficacy and tolerability of multiple prophylactic treatments for vestibular migraine (VM), including β-blockers, calcium channel blockers, antiseizure medications, and antidepressants such as tricyclics and serotonin-noradrenaline reuptake inhibitors. Methods: PubMed, Web of Science, Embase, and Cochrane Center for Clinical Trials were systematically searched for relevant randomized clinical trials (RCTs) from March 2023 to May 2023. Studies on the efficacy and tolerability of prophylactic treatments for VM were included. Efficacy was measured using the average vertigo frequency per month and dizziness handicap inventory (DHI) improvement after 3-6 months of treatment. Tolerability was measured by the number of patients reporting at least one adverse event (AE). Network meta-analyses were performed according to a Bayesian framework and a random-effects model based on odds ratios or mean differences (MDs) and 95% confidence intervals (CIs). A sequence of ranking probability was calculated according to the surface under the cumulative ranking (SUCRA) curve. This network meta-analysis was previously registered with PROSPERO (CRD42023422258). Results: Five RCTs comprising 334 patients were analyzed by synthesizing the published evidence. Considering the examined prophylactic therapies, there is significant evidence that valproate acid (VPA) is superior to placebo or abortive treatment alone (MD = -4.12, 95% CI = -8.09, -0.15) in reducing the frequency of vertigo. Flunarizine (MD = 20.00, 95% CI = 10.90, 29.10), valproate acid (MD = 18.88, 95% CI = 10.42, 27.34), and venlafaxine (MD = 11.48, 95% CI = 9.84, 13.12) were significantly more effective than placebo or abortive treatment in reducing DHI. VPA most strongly reduced the frequency of vertigo according to SUCRA, but it ranked third-to-last in tolerability. Flunarizine ranked best in DHI improvement but worst in tolerability. Metoprolol ranked worst for efficacy but best for tolerability. Conclusion: VPA and flunarizine reduced the frequency of vertigo and improved DHI, but they had unfavorable tolerability. The effects of metoprolol on vertigo require further study. Given the low certainty and limited sample, additional head-to-head RCTs are warranted to further confirm efficacy. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/; Identifier CRD42023422258.

Permanent non-progressive cinnarizine and flunarizine-induced parkinsonism: An under-recognized tardive syndrome in the elderly?

Secondary parkinsonism induced by exposure to dopamine (DA) receptor antagonists as first and second generation antipsychotics, DA storage depleters, calcium channel blockers, benzamides substituted and other classes of drugs is traditionally believed to be completely reversible in most of patients following withdrawal of the offending drug even though after a variable time delay. The lack of recovery or initial full recovery with subsequent development of progressive parkinsonism has been regarded to result from an underlying subclinical degenerative process like PD unmasked by the inducing drug. These well-recognized clinical outcomes of drug-induced parkinsonism (DIP) have disregarded the existence of another outcome, characterized by permanent non-progressive parkinsonism. This syndrome may fullfil the criteria of tardive parkinsonism, a controversial entity currently referred to as a persistent condition without indication of its long-term course and clinical features. On reviewing the published literature on DIP, we have identified two prospective long-term follow-up of elderly patients in which parkinsonism induced by the calcium channel antagonists cinnarizine and flunarizine became permanent and non-progressive following drug discontinuation in a non-negligible proportion of patients, consistent with the clinical concept of a true tardive syndrome, according to currently accepted criteria. The authors hypothesize that the development of tardive parkinsonism might be due to a neurotoxic effect of the pharmacodynamic proprieties of the calcium channel blockers and their metabolites, exerted on post-synaptic striatal neurons and/or a neurotoxic damage on presynaptic DA neurons in patients without an underlying subclinical degenerative parkinsonism, so accounting for the stable and non-progressive course over time.

Mitolysosome exocytosis: a novel mitochondrial quality control pathway linked with parkinsonism-like symptoms

Quality control of mitochondria is essential for their homeostasis and function. Light chain 3 (LC3) associated autophagosomes-mediated mitophagy represents a canonical mitochondrial quality control pathway. Alternative quality control processes, such as mitochondrial-derived vesicles (MDVs), have been discovered, but the intact mitochondrial quality control remains unknown. We recently discovered a novel mitolysosome exocytosis mechanism for mitochondrial quality control in flunarizine (FNZ)-induced mitochondria clearance, where autophagosomes are not required, but rather mitochondria are engulfed directly by lysosomes, mediating mitochondrial secretion. As FNZ results in parkinsonism, we propose that excessive mitolysosome exocytosis is the cause.

Migraine Pharmacological Treatment and Cognitive Impairment: Risks and Benefits

Migraine is a common neurological disorder impairing the quality of life of patients. The condition requires, as an acute or prophylactic line of intervention, the frequent use of drugs acting on the central nervous system (CNS). The long-term impact of these medications on cognition and neurodegeneration has never been consistently assessed. The paper reviews pharmacological migraine treatments and discusses their biological and clinical effects on the CNS. The different anti-migraine drugs show distinct profiles concerning neurodegeneration and the risk of cognitive deficits. These features should be carefully evaluated when prescribing a pharmacological treatment as many migraineurs are of scholar or working age and their performances may be affected by drug misuse. Thus, a reconsideration of therapy guidelines is warranted. Furthermore, since conflicting results have emerged in the relationship between migraine and dementia, future studies must consider present and past pharmacological regimens as potential confounding factors.

Vestibular migraine treatment: a comprehensive practical review

Vestibular migraine is an underdiagnosed but increasingly recognised neurological condition that causes episodic vertigo associated with other features of migraine. It is now thought to be the most common cause of spontaneous (non-positional) episodic vertigo, affecting up to 1% of the population. A meta-analysis of preventative treatments for vestibular migraine was published in 2021 but the authors were unable to establish a preferred treatment strategy due to low quality of evidence and heterogeneity of study design and outcome reporting. There remains therefore a clinical need for pragmatic management guidelines specific to vestibular migraine using the available evidence. Here we provide a practical review utilising a systematic qualitative assessment of the evidence for abortive and preventative interventions in adults. The overall evidence base for vestibular migraine treatment is of low quality. Nevertheless, we provide practical treatment recommendations based on the available evidence and our experience to help guide clinicians treating patients with vestibular migraine. We also discuss how future clinical trials could be designed to improve the quality of evidence in this condition.

Mitolysosome exocytosis, a mitophagy-independent mitochondrial quality control in flunarizine-induced parkinsonism-like symptoms

Mitochondrial quality control plays an important role in maintaining mitochondrial homeostasis and function. Disruption of mitochondrial quality control degrades brain function. We found that flunarizine (FNZ), a drug whose chronic use causes parkinsonism, led to a parkinsonism-like motor dysfunction in mice. FNZ induced mitochondrial dysfunction and decreased mitochondrial mass specifically in the brain. FNZ decreased mitochondrial content in both neurons and astrocytes, without affecting the number of nigral dopaminergic neurons. In human neural progenitor cells, FNZ also induced mitochondrial depletion. Mechanistically, independent of ATG5- or RAB9-mediated mitophagy, mitochondria were engulfed by lysosomes, followed by a vesicle-associated membrane protein 2- and syntaxin-4-dependent extracellular secretion. A genome-wide CRISPR knockout screen identified genes required for FNZ-induced mitochondrial elimination. These results reveal not only a previously unidentified lysosome-associated exocytosis process of mitochondrial quality control that may participate in the FNZ-induced parkinsonism but also a drug-based method for generating mitochondria-depleted mammal cells.

Dopamine transporter (DAT) imaging in Parkinson's disease and related disorders

This review gives an insight into the beginnings of dopamine transporter (DAT) imaging in the early 1990s, focussing on single photon emission tomography (SPECT). The development of the method and its consolidation as a now widely used clinical tool is described. The role of DAT-SPECT in the diagnosis and differential diagnosis of PD, atypical parkinsonian syndromes and several other different neurological disorders is reviewed. Finally the clinical research using DAT-SPECT as a biomarker for the progression of PD, for the detection of a preclinical dopaminergic lesion and its correlation with neuropathological findings is outlined.

(-)-OSU6162 in the treatment of fatigue and other sequelae after aneurysmal subarachnoid hemorrhage: a double-blind, randomized, placebo-controlled study

OBJECTIVE

Fatigue after aneurysmal subarachnoid hemorrhage (aSAH) is common and usually long-lasting, and it has a considerable negative impact on health-related quality of life (HRQOL), social functioning, and the ability to return to work (RTW). No effective treatment exists. The dopaminergic regulator (-)-OSU6162 has shown promising results regarding the mitigation of fatigue in various neurological diseases, and therefore the authors aimed to investigate the efficacy of (-)-OSU6162 in alleviating fatigue and other sequelae after aSAH.

METHODS

A double-blind, randomized, placebo-controlled, single-center trial was performed in which 96 participants with post-aSAH fatigue were administered 30-60 mg/day of (-)-OSU6162 or placebo over a period of 12 weeks. Efficacy was assessed using the Fatigue Severity Scale (FSS), the Mental Fatigue Scale (MFS), the Beck Anxiety Inventory (BAI), the Beck Depression Inventory II (BDI-II), the SF-36 questionnaire, and a neuropsychological test battery. Assessments were performed at baseline, after 1, 4, 8, and 12 weeks of treatment, and at follow-up, 8 weeks after treatment.

RESULTS

The 96 participants with post-aSAH fatigue were randomized to treatment with (-)-OSU6162 (n = 49) or placebo (n = 47). The FSS, MFS, and BDI scores improved significantly in both groups after 12 weeks of treatment, whereas the BAI scores improved in the placebo group only. HRQOL improved significantly in the SF-36 domain "Vitality" in both groups. Neuropsychological test performances were within the normal range at baseline and not affected by treatment. The FSS score was distinctly improved in patients with complete RTW upon treatment with (-)-OSU6162. Concomitant use of antidepressants improved the efficacy of (-)-OSU6162 on the FSS score at week 1 beyond the placebo response, and correspondingly the use of beta- or calcium-channel blockers improved the (-)-OSU6162 efficacy beyond the placebo response in MFS scores at week 4 of treatment. There was a significant correlation between improvement in FSS, BAI, and BDI scores and the plasma concentration of (-)-OSU6162 at the dose of 60 mg/day. No serious adverse events were attributable to the treatment, but dizziness was reported more often in the (-)-OSU6162 group.

CONCLUSIONS

Fatigue and other sequelae after aSAH were similarly alleviated by treatment with (-)-OSU6162 and placebo. (-)-OSU6162 improved fatigue, as measured with the FSS score, significantly in patients with complete RTW. There seemed to be synergetic effects of (-)-OSU6162 and medications interfering with dopaminergic pathways that should be explored further. The strong placebo response may be exploited in developing nonpharmacological treatment programs for post-aSAH fatigue.

Comprehensive management of adults with chronic migraine: Clinical practice guidelines in Mexico

Introduction:

Migraine is a polygenic multifactorial disorder with a neuronal initiation of a cascade of neurochemical processes leading to incapacitating headaches. Headaches are generally unilateral, throbbing, 4–72 h in duration, and associated with nausea, vomiting, photophobia, and sonophobia. Chronic migraine (CM) is the presence of a headache at least 15 days per month for ≥3 months and has a high global impact on health and economy, and therapeutic guidelines are lacking.

Methods:

Using the Grading of Recommendations, Assessment, Development, and Evaluations system, we conducted a search in MEDLINE and Cochrane to investigate the current evidence and generate recommendations of clinical practice on the identification of risk factors and treatment of CM in adults.

Results:

We recommend avoiding overmedication of non-steroidal anti-inflammatory drugs (NSAIDs); ergotamine; caffeine; opioids; barbiturates; and initiating individualized prophylactic treatment with topiramate eptinezumab, galcanezumab, erenumab, fremanezumab, or botulinum toxin. We highlight the necessity of managing comorbidities initially. In the acute management, we recommend NSAIDs, triptans, lasmiditan, and gepants alone or with metoclopramide if nausea or vomiting. Non-pharmacological measures include neurostimulation.

Conclusions:

We have identified the risk factors and treatments available for the management of CM based on a grading system, which facilitates selection for individualized management.

Oral Chinese Herbal Medicine as Prophylactic Treatment for Episodic Migraine in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The prophylactic effects of Chinese herbal medicine (CHM) for migraine were examined in numerous clinical trials. This review aimed to analyze the effectiveness and safety of CHM as prophylactic treatment of migraine compared to flunarizine.

METHODS

Nine databases were searched for randomized controlled trials (RCTs) that evaluated effects of CHM for episodic migraine prophylaxis compared to flunarizine, published before March 2019.

RESULTS

Thirty-five RCTs with 2,840 participants met the inclusion criteria, and 31 of them were included in meta-analyses. The overall meta-analysis indicated that, when compared to flunarizine, CHM reduced the frequency of migraine attacks at the end of treatment (EoT) (21 studies, mean difference (MD) -1.23, 95% confidence interval (CI) (-1.69, -0.76)) and at the end of follow-up (EoFU) (five studies, MD -0.96, 95% CI (-1.70, -0.21)). Subgroup analyses based on the treatment duration, follow-up duration, and the dosage of flunarizine showed that CHM was superior to or comparable with flunarizine in reducing migraine frequency. Similar results were also found for secondary outcomes such as the pain visual analogue scale, migraine duration, responder rate, and acute medication usage. In particular, the studies that used CHM containing herb pairs (Chuan Xiong plus Bai Zhi and Chuan Xiong plus Tian Ma) showed promising results. However, the certainty of this evidence was evaluated as "low" or "very low" using the Grading of Recommendations, Assessment, Development and Evaluations approach.

CONCLUSION

CHM appeared to be comparable with flunarizine in reducing the frequency of episodic migraine attacks in adults at EoT and EoFU and well-tolerated by participants, regardless of the treatment duration, follow-up duration, and dosage of flunarizine. Due to the low certainty of the evidence, the suggested promising prophylactic outcomes require higher quality evidence from further rigorous RCTs.

Cinnarizine- and flunarizine-associated movement disorder: a literature review

Introduction

Cinnarizine (CNZ) and flunarizine (FNZ) belong to the calcium channel blockers class of medication.

Main text

The aim of this literature review is to evaluate the clinical epidemiological profile, pathological mechanisms, and management of CNZ/FNZ-associated movement disorder (MD). Relevant reports in six databases were identified and assessed by two reviewers without language restriction. One hundred and seventeen reports containing 1920 individuals who developed a CNZ/FNZ-associated MD were identified. The MD encountered were 1251 parkinsonism, 23 dyskinesias, 11 akathisia, 16 dystonia, and 5 myoclonus, and in the group not clearly defined, 592 extrapyramidal symptoms, 19 tremors, 2 bradykinesia, and 1 myokymia. The predominant sex was female with a percentage of 72.69% (466/641). The mean age was 74.49 (SD, 7.88) years. The mean CNZ dose was 148.19 mg (SD, 42.51) and for the FNZ dose, 11.22 mg (5.39). The mean MD onset and recovery were 1.83 years (SD, 1.35) and 3.71 months (SD, 1.26). In the subgroup of subjects that had improvement of the symptoms, the complete recovery was achieved within 6 months of the drug withdrawal in almost all subjects (99%). The most common management was drug withdrawal. A complete recovery was observed in 93.77% of the patients (437/466).

Conclusions

CNZ/FNZ-associated MD was extensively reported in the literature. Parkinsonism was the most well described. Myoclonus (MCL) was the poorest described MD with missing data about the neurological examination and electrodiagnostic studies. The knowledge of this disorder probably can contribute to the understanding of the other drug-induced MDs.

Discovery of HIV entry inhibitors via a hybrid CXCR4 and CCR5 receptor pharmacophore-based virtual screening approach

Chemokine receptors are key regulators of cell migration in terms of immunity and inflammation. Among these, CCR5 and CXCR4 play pivotal roles in cancer metastasis and HIV-1 transmission and infection. They act as essential co-receptors for HIV and furnish a route to the cell entry. In particular, inhibition of either CCR5 or CXCR4 leads very often the virus to shift to a more virulent dual-tropic strain. Therefore, dual receptor inhibition might improve the therapeutic strategies against HIV. In this study, we aimed to discover selective CCR5, CXCR4, and dual CCR5/CXCR4 antagonists using both receptor- and ligand-based computational methods. We employed this approach to fully incorporate the interaction attributes of the binding pocket together with molecular dynamics (MD) simulations and binding free energy calculations. The best hits were evaluated for their anti-HIV-1 activity against CXCR4- and CCR5-specific NL4.3 and BaL strains. Moreover, the Ca²⁺ mobilization assay was used to evaluate their antagonistic activity. From the 27 tested compounds, three were identified as inhibitors: compounds 27 (CCR5), 6 (CXCR4) and 3 (dual) with IC₅₀ values ranging from 10.64 to 64.56 μM. The binding mode analysis suggests that the active compounds form a salt bridge with the glutamates and π-stacking interactions with the aromatic side chains binding site residues of the respective co-receptor. The presented hierarchical virtual screening approach provides essential aspects in identifying potential antagonists in terms of selectivity against a specific co-receptor. The compounds having multiple heterocyclic nitrogen atoms proved to be relatively more specific towards CXCR4 inhibition as compared to CCR5. The identified compounds serve as a starting point for further development of HIV entry inhibitors through synthesis and quantitative structure-activity relationship studies.

Trimetazidine-Induced Parkinsonism: A Systematic Review

Importance: Trimetazidine (TMZ) is a medication given to patients with stable coronary artery disease. While it is reportedly well-tolerated, there are increasing numbers of reports of adverse events such as parkinsonism.

Objectives: The purpose of this study was to systematically review the currently available literature on TMZ-induced parkinsonism.

Evidence Review: A search of Scopus, MEDLINE, EMBASE, the Cochrane Library, the Health Technology Assessment Database, PubMed, Science Direct, and Google Scholar was conducted on or before November 7, 2019. The literature search included cohort studies, prospective and/or retrospective studies, meta-analysis, and other systematic reviews published as an original article, including abstracts and full texts. We included patients taking TMZ who developed one or more of the parkinsonian symptoms of bradykinesia, tremors, rigidity, and postural instability, where these symptoms improved after withdrawal of the said medication.

Findings: There are currently five studies on TMZ use and associated parkinsonism. The literature included two case reports, one case series, and one retrospective and one prospective study. We found no results from randomized clinical trials. Overall, 88 patients developed TMZ-induced parkinsonism. Regression of parkinsonism was reported in all of the participants after withdrawal of TMZ. A total of 49 patients (55.7%) had complete regression of symptoms, while 39 patients (44.3%) had significant reduction of symptoms. The duration between TMZ (dose, 60–80 mg/day) intake and onset of symptoms ranged from 4 months to 20 years. The most commonly reported extrapyramidal symptoms were akinesia, rigidity, postural disturbances, and gait disorders, which were usually mild and symmetric.

Conclusions and Relevance: The current literature suggests that TMZ can induce parkinsonism that is reversible with drug withdrawal. It is warranted to examine patients, especially the elderly, on TMZ for parkinsonian symptoms and those with pre-existing neurodegenerative diseases. Further studies are needed to assess the risk-benefit ratio of this drug, especially in the elderly age group.

Flunarizine Induced Parkinsonism in Migraine Group: A Nationwide Population-Based Study

Background: Flunarizine (Fz) is a first-line prophylactic medication that is widely used in migraine. However, Fz has been recognized as a potential cause of drug-induced parkinsonism for a long time. However, to our knowledge, there has been no population-based subgroup analyses for Fz-induced parkinsonism (FIP) in migraine patients. Methods: Data were obtained from the Taiwan's National Health Insurance Research Database. The study comprised 6,470 migraine patients who were divided into two groups, based on their exposure or non-exposure to Fz. Results: During the study period (2000-2012), the incidence rate of parkinsonism was 1.92 and 8.72 per 1,000 person-years in the control and Fz -treated groups, respectively. In the study population, the adjusted hazard ratio was 4.07 (95% confidence interval CI: 2.84-5.85). In 45-64-year old subjects and ≥ 65-year old subjects, the risk of FIP was 3.18 times (95% CI = 1.63-6.20) and 4.89 times (95% CI = 3.09-7.72) more than that in the controls. The Fz-treated subjects with comorbidities also had a higher risk (4.54, 95% CI: 3.14-6.57). An average annual cumulative Fz dose > 445 mg was accompanied by the greatest risk of FIP; Fz use for >60 days is a cut-off point for predicting future FIP. Conclusion: At the population level, this study showed a complete picture of FIP in migraine patients. FIP is associated with older age, history of comorbidities, exposure to high-dose of Fz, and longer duration of exposure to Fz.

Flunarizine related movement disorders: a nationwide population-based study

Flunarizine (fz) causes side effects such as movement disorders (MDs). We investigated risk factors associated with fz-related MDs. Participants were recruited from the longitudinal health insurance databases and included patients who took fz for more than 1 month. Patients with one of the underlying diseases, or with concomitant drug use (antipsychotics, metoclopramide or reserpine), and those diagnosed with MDs before fz use were excluded. Fz-related MD was defined as a new diagnosis of parkinsonism or hyperkinetic syndrome including dyskinesia or secondary dystonia during fz use or within 3 months after drug discontinuation. After exposure, 288 individuals had fz-related MDs (parkinsonism, n = 240; hyperkinesia, n = 48). Risk factors associated with these disorders were higher-dose exposure (cumulative defined daily dose [cDDD] ≥87.75, odds ratio [OR]: 3.80; 95% CI: 2.61–5.52), older age (OR: 1.07; 95% CI: 1.06–1.09), history of essential tremor (OR: 6.39; 95% CI: 2.29–17.78) and cardiovascular disease (CVD) (OR: 1.47; 95% CI: 1.14–1.9). The optimal value of cDDD to predict MDs was 58.5 (sensitivity: 0.67, specificity: 0.60), indicating an overall exposure of 585 mg. Higher exposure dose and duration, older age, history of essential tremor, and CVD were associated with fz-associated MDs. Clinicians ought to watch for extrapyramidal side effects when prescribing fz.

Trimetazidine and parkinsonism: A prospective study

BACKGROUND

Although trimetazidine may induce parkinsonian symptoms in some patients, no systematic characterization has been reported on parkinsonism occurring during trimetazidine treatment since the first case reports.

OBJECTIVE

To systematically investigate parkinsonism occurring during trimetazidine use.

METHODS

Thirty-three consecutive patients on trimetazidine treatment with previously unrecognized parkinsonian symptoms were enrolled. Detailed neurological and neuropsychological examinations were performed at baseline and 1 and 12 months after trimetazidine withdrawal. In cases with persisting parkinsonian symptoms and suspected de novo Parkinson's disease, antiparkinsonian treatment was initiated. Twenty of the 33 patients underwent DaTSCAN imaging.

RESULTS

After trimetazidine withdrawal, parkinsonism was completely resolved in 11 cases. The comparison of baseline data of patients with reversible and persisting parkinsonism showed that trimetazidine-induced reversible parkinsonism was mainly characterized by akinesia, rigidity, postural instability and gait disturbances (PIGD; PIGD scores: 5.3 ± 3.8 vs. 2.0 ± 1.6 points, p = 0.006) rather than tremors (tremor scores: 1.5 ± 2.2 vs. 7.7 ± 4.6 points, p = 0.000). Trimetazidine-induced reversible parkinsonism was also more symmetrical (asymmetry index: 3.1 ± 3.6 vs. 40.1 ± 22.2, p = 0.000) and milder in severity (MDS-UPDRS Part III. scores: 10.5 ± 19. vs. 30.5 ± 11.3, p = 0.040) than nonreversible parkinsonism. DaTSCAN images were normal in all trimetazidine-induced reversible parkinsonism patients, while these images were abnormal in every patient with nonreversible parkinsonism. In cases of nonreversible parkinsonism, preexisting, incipient Parkinson's disease was suspected by clinical appearance and a good response to antiparkinsonian medication.

CONCLUSIONS

Mild and symmetrical appearance of parkinsonism with normal DaTSCAN results can indicate drug-induced parkinsonism. Trimetazidine discontinuation generally results in permanent remission in such cases.

Flunarizine and the risk of parkinsonism in a newly diagnosed type 2 diabetic population in Taiwan: A nested case-control study

Previous studies demonstrated that both diabetes and flunarizine use can increase the risk of parkinsonism. The aim of the current study was to investigate the risk of developing parkinsonism after flunarizine treatment, in a cohort of patients newly diagnosed with type 2 diabetes. We conducted a nested case-control study of a type 2 diabetic cohort from the Taiwan Longitudinal Health Insurance Database 2005 (LHID 2005). Each incident case of parkinsonism, during the period from 2001 to 2013, was randomly matched with 3-10 controls, according to age, sex, calendar year of cohort entry, and the duration of follow-up. Conditional logistic regression was used to estimate the odds ratio (OR) of parkinsonism associated with flunarizine use. The cohort consisted of 44,644 patients with newly diagnosed type 2 diabetes from 2001 to 2013, of whom 464 patients had a parkinsonism event during the follow-up period. The adjusted OR of parkinsonism with relation to flunarizine use was 2.75 (95% confidence interval: 2.26-3.36). There were also duration- and dose-response effects. Compared to those who had not used it, the OR for developing parkinsonism was 1.77 for patients who used flunarizine for less than 1 month. When the exposure period expanded over 3 months, the OR increased to 7.03. Our findings suggested that flunarizine use is a potential risk factor for parkinsonism in patients with newly diagnosed type 2 diabetes, especially when the drug is persistently used for over 3 months.

Cerebral dopamine deficiency, plasma monoamine alterations and neurocognitive deficits in adults with phenylketonuria

BACKGROUND

Phenylketonuria (PKU), a genetic metabolic disorder that is characterized by the inability to convert phenylalanine to tyrosine, leads to severe intellectual disability and other cerebral complications if left untreated. Dietary treatment, initiated soon after birth, prevents most brain-related complications. A leading hypothesis postulates that a shortage of brain monoamines may be associated with neurocognitive deficits that are observable even in early-treated PKU. However, there is a paucity of evidence as yet for this hypothesis.

METHODS

We therefore assessed in vivo striatal dopamine D2/3 receptor (D2/3R) availability and plasma monoamine metabolite levels together with measures of impulsivity and executive functioning in 18 adults with PKU and average intellect (31.2 ± 7.4 years, nine females), most of whom were early and continuously treated. Comparison data from 12 healthy controls that did not differ in gender and age were available.

RESULTS

Mean D2/3R availability was significantly higher (13%; p = 0.032) in the PKU group (n = 15) than in the controls, which may reflect reduced synaptic brain dopamine levels in PKU. The PKU group had lower plasma levels of homovanillic acid (p < 0.001) and 3-methoxy-4-hydroxy-phenylglycol (p < 0.0001), the predominant metabolites of dopamine and norepinephrine, respectively. Self-reported impulsivity levels were significantly higher in the PKU group compared with healthy controls (p = 0.033). Within the PKU group, D2/3R availability showed a positive correlation with both impulsivity (r = 0.72, p = 0.003) and the error rate during a cognitive flexibility task (r = 0.59, p = 0.020).

CONCLUSIONS

These findings provide further support for the hypothesis that executive functioning deficits in treated adult PKU may be associated with cerebral dopamine deficiency.

Extrapyramidal symptoms after exposure to calcium channel blocker-flunarizine or cinnarizine

Purpose

Flunarizine (fz) and cinnarizine (cz) have well-known extrapyramidal side effects (EPSEs). The aim of this study was to evaluate the incidence and occurrence time of cz- and fz-related EPSEs.

Method

Patients who took fz or cz for more than 1 month were identified from the longitudinal health insurance database 2005 and 2010. Excluded were patients with any of the underlying diseases that may cause parkinsonism. Drug-induced EPSEs were defined as the new diagnosis of parkinsonism, dyskinesia, or secondary dystonia during drug use or within 3 months after discontinuing the medication. Age- and sex-matched controls were included in this study.

Results

Recruited for analysis were individuals who took fz (n = 26,133) and cz (n = 7186). The incidence rates of fz- and cz-induced EPSEs were 21.03 and 10.3 per 10,000 person-months, respectively. The hazard ratios (HRs) of EPSEs among fz and cz subjects were 8.03 (95% CI 6.55–9.84) and 3.41 (95% CI 2.50–4.63) when compared with the control individuals. Both fz and cz patients had a higher cumulative incidence of EPSEs than their control individuals (p < 0.001). Among subjects who took fz, the incidence of EPSEs was higher in the second than first year of drug exposure (45.59 vs 21.03 per 10,000 person-months).

Conclusions

Fz and cz significantly increased the risk of parkinsonism, dyskinesia, and dystonia. Potential benefits and risks should be weighed when considering long-term use of these drugs especially fz.

Electronic supplementary material

The online version of this article (doi:10.1007/s00228-017-2247-x) contains supplementary material, which is available to authorized users.

Anxiolytic Properties of Trimetazidine in Experimental Models of Increased Anxiety

Effect of trimetazidine (20 and 30 mg/kg) on elevated plus maze behavior of rodents was assessed in the genetic and pharmacological anxiety models. Single intraperitoneal injection of trimetazidine in a dose of 20 mg/kg prevented anxiety development in highly emotional male BALB/c mice and increased the time spent in open arms of the maze. In outbred male rats receiving 10% ethanol solution for 20 weeks, trimetazidine administered intraperitoneally in a dose of 20 mg/kg for 28 days abolished ethanol withdrawal-induced anxiogenesis developed against the background of 4-week alcohol deprivation: it increased the time spent in open arms, the number of entries into open arms, and total locomotor activity in the maze. Anxiolytic properties of trimetazidine were not inferior to those of the non-benzodiazepine anxiolytic Afobazole (fabomotizole) in acute and chronic administration.

A Comparative Effectiveness Meta-Analysis of Drugs for the Prophylaxis of Migraine Headache

Objective

To compare the effectiveness and side effects of migraine prophylactic medications.

Design

We performed a network meta-analysis. Data were extracted independently in duplicate and quality was assessed using both the JADAD and Cochrane Risk of Bias instruments. Data were pooled and network meta-analysis performed using random effects models.

Data Sources

PUBMED, EMBASE, Cochrane Trial Registry, bibliography of retrieved articles through 18 May 2014.

Eligibility Criteria for Selecting Studies

We included randomized controlled trials of adults with migraine headaches of at least 4 weeks in duration.

Results

Placebo controlled trials included alpha blockers (n = 9), angiotensin converting enzyme inhibitors (n = 3), angiotensin receptor blockers (n = 3), anticonvulsants (n = 32), beta-blockers (n = 39), calcium channel blockers (n = 12), flunarizine (n = 7), serotonin reuptake inhibitors (n = 6), serotonin norepinephrine reuptake inhibitors (n = 1) serotonin agonists (n = 9) and tricyclic antidepressants (n = 11). In addition there were 53 trials comparing different drugs. Drugs with at least 3 trials that were more effective than placebo for episodic migraines included amitriptyline (SMD: -1.2, 95% CI: -1.7 to -0.82), -flunarizine (-1.1 headaches/month (ha/month), 95% CI: -1.6 to -0.67), fluoxetine (SMD: -0.57, 95% CI: -0.97 to -0.17), metoprolol (-0.94 ha/month, 95% CI: -1.4 to -0.46), pizotifen (-0.43 ha/month, 95% CI: -0.6 to -0.21), propranolol (-1.3 ha/month, 95% CI: -2.0 to -0.62), topiramate (-1.1 ha/month, 95% CI: -1.9 to -0.73) and valproate (-1.5 ha/month, 95% CI: -2.1 to -0.8). Several effective drugs with less than 3 trials included: 3 ace inhibitors (enalapril, lisinopril, captopril), two angiotensin receptor blockers (candesartan, telmisartan), two anticonvulsants (lamotrigine, levetiracetam), and several beta-blockers (atenolol, bisoprolol, timolol). Network meta-analysis found amitriptyline to be better than several other medications including candesartan, fluoxetine, propranolol, topiramate and valproate and no different than atenolol, flunarizine, clomipramine or metoprolol.

Conclusion

Several drugs good evidence supporting efficacy. There is weak evidence supporting amitriptyline’s superiority over some drugs. Selection of prophylactic medication should be tailored according to patient preferences, characteristics and side effect profiles.

Parkinsonism in phenylketonuria: a consequence of dopamine depletion?

Phenylketonuria (PKU) is caused by a deficiency or inactivity of the enzyme phenylalanine hydroxylase that converts phenylalanine (Phe) to tyrosine (Tyr). It has been proposed that a reduction of brain Tyr levels, as well as reduced activity of the key regulatory enzyme of dopamine (DA) synthesis tyrosine hydroxylase, leads to a depletion in DA activity in patients with PKU. We report a case of a 56-year-old woman with an intellectual disability due to late diagnosis of PKU and parkinsonism, with a modest clinical response to levodopa therapy.We hypothesize that the signs of parkinsonism might be caused by the depletion of DA activity in the brain. Clinicians should be alert on parkinsonian symptoms in patients with PKU, particularly in those treated with agents that negatively influence DA transmission.

Efficacy and safety of cinnarizine in the prophylaxis of migraine in children: a double-blind placebo-controlled randomized trial

BACKGROUND

In spite of the high occurrence of migraine headaches in school-age children, there are currently no approved and widely accepted pharmacologic agents for migraine prophylaxis in children. Our previous open-label study in children revealed the efficacy of cinnarizine, a calcium channel blocker, in migraine prophylaxis. A placebo-controlled trial was conducted to demonstrate the efficacy and safety of cinnarizine in the prophylaxis of migraine in children.

TRIAL DESIGN

A double-blind, placebo-controlled, parallel-group study conducted in a tertiary medical center in Tehran, Iran.

METHODS

Children (5-17 years) who experienced migraines with and without aura, as defined on the basis of 2004 International Headache Society criteria, were recruited into the study. Children were excluded if they had complicated migraine, epilepsy, or a history of use of migraine prophylactic agents. Each participant was randomly assigned to receive cinnarizine (a single 1.5 mg/kg/day dose in children weighing less than 30 kg and a single 50 mg dose in children weighing more than 30 kg, administered at bedtime) or placebo. The frequency, severity, and duration of headaches over the trial period were assessed and adverse effects were monitored.

RESULTS

A total of 68 children (34 in each group) with migraine were enrolled and 62 participants completed the study. After 3 months of taking cinnarizine or placebo, children in both groups experienced significantly reduced frequency, severity, and duration of headaches compared with baseline measurements (P < 0.001). However, compared with 31.3% of children in the placebo group, 60% of children in the cinnarizine group reported more than 50% reduction in monthly headache frequency (P = 0.023), suggesting that cinnarizine was significantly more effective than placebo in reducing the frequency of headaches. No serious adverse effects of the medications were observed in the treated children, including no abnormal weight gain or extrapyramidal signs.

CONCLUSION

Our results indicate that the use of cinnarizine at doses administered in this study is effective and safe for prophylaxis of migraine headaches in children.

Antipsychotic-like effect of trimetazidine in a rodent model

Trimetazidine (TMZ) has been used as an anti-ischemic agent for angina pectoris, chorioretinal disturbances, and vertigo. Also, it can induce extrapyramidal type adverse reaction such as parkinsonism, gait disorder, and tremor via blockade of D2 receptors. In the present study, we evaluated the effect of TMZ on novelty-induced rearing behavior and apomorphine-induced stereotypy behavior in male rats. Four groups of rat (n = 7) were administrated with TMZ (10 and 20 mg/kg, i.p.), chlorpromazine (1 mg/kg, i.p.), or isotonic saline. One hour later, apomorphine (2 mg/kg, s.c.) was administrated to each rat. Our results showed that both doses of TMZ significantly decreased the rearing behavior in rats, whereas the decrease with chlorpromazine was higher. TMZ also decreased the stereotypy scores in a dose-dependent manner. We concluded that TMZ has beneficial effects on rearing behavior and stereotypy, which are accepted to be indicators of antipsychotic effect. Taken together, with its antioxidative and cytoprotective properties, TMZ is worthy of being investigated for its anti-psychotic effects as a primary or an adjunctive drug.

Nonmotor symptoms in drug-induced parkinsonism and drug-naïve Parkinson disease

BACKGROUND

The clinical manifestations of drug-induced parkinsonism (DIP) and Parkinson disease (PD) are nearly indistinguishable, making it difficult to differentiate DIP from PD, especially in the early stages. We compared non-motor symptoms between patients with DIP and those with drug-naïve PD in the early stages using the Non Motor Symptoms Scale (NMSS).

METHODS

We prospectively enrolled 28 patients with DIP, 35 patients with drug-naïve PD, and 32 controls with no history of neurological diseases or related medical problems. We investigated demographic characteristics, medical and drug history, parkinsonian motor symptoms, and non-motor symptoms. We used the NMSS to evaluate non-motor symptoms in all patients.

RESULTS

The total NMSS scores were higher in patients with PD than those with DIP, as were the scores for certain domains, including the cardiovascular, sleep/fatigue, urinary, sexual, and miscellaneous domains. When controlling for age and gender, the correlation analysis revealed that scores for urinary symptoms (urgency, frequency and nocturia), sleep disturbances (daytime sleep, restless legs), concentration, taste or smell were significantly associated with PD.

CONCLUSIONS

Our data suggest that non-motor symptoms, particularly urinary symptoms, excessive daytime sleepiness, restless leg syndrome, attention deficit and hyposmia may be helpful to differentiate between DIP and PD in the early stages.

A molecular basis for the increased vulnerability of substantia nigra dopamine neurons in aging and Parkinson's disease

Parkinson's disease (PD) is a common neurodegenerative disorder of unknown etiology. There is no cure or proven strategy for slowing the progression of the disease. Although there are signs of pathology in many brain regions, the core symptoms of PD are attributable to the selective degeneration of dopaminergic neurons in the substantia nigra pars compacta. A potential clue to the vulnerability of these neurons is an increasing reliance with age upon L-type Ca(2+) channels with a pore-forming Cav1.3 subunit to support autonomous activity. This reliance could pose a sustained stress on mitochondrial ATP generating oxidative phosphorylation, accelerating cellular aging and death. Systemic administration of isradipine, a dihydropyridine blocker of these channels, forces dopaminergic neurons in rodents to revert to a juvenile, L-type Ca(2+) channel independent mechanism to generate autonomous activity. This "rejuvenation" confers protection against toxins that produce experimental Parkinsonism, pointing to a potential neuroprotective strategy for PD. Their decades-long track record of safe use in the treatment of hypertension makes dihydropyridines particularly attractive as a therapeutic tool in PD.

Calcium, ageing, and neuronal vulnerability in Parkinson's disease

Parkinson's disease is a common neurodegenerative disorder of unknown cause. There is no cure or proven strategy for slowing the progression of the disease. Although there are signs of pathology in many brain regions, the core symptoms of Parkinson's disease are attributable to the selective degeneration of dopaminergic neurons in the substantia nigra pars compacta. A potential clue to the vulnerability of these neurons is their increasing reliance on Ca(2+) channels to maintain autonomous activity with age. This reliance could pose a sustained metabolic stress on mitochondria, accelerating cellular ageing and death. The Ca(2+) channels underlying autonomous activity in dopaminergic neurons are closely related to the L-type channels found in the heart and smooth muscle. Systemic administration of isradipine, a dihydropyridine blocker of L-type channels, forces dopaminergic neurons in rodents to revert to a juvenile, Ca(2+)-independent mechanism to generate autonomous activity. More importantly, reversion confers protection against toxins that produce experimental parkinsonism, pointing to a potential neuroprotective strategy for Parkinson's disease with a drug class that has been used safely in human beings for decades. These studies also suggest that, although genetic and environmental factors can hasten its onset, Parkinson's disease stems from a distinctive neuronal design common to all human beings, making its appearance simply a matter of time.

Drug-induced parkinsonism in the elderly

Drug-induced parkinsonism is primarily caused by drugs that interfere with dopamine stimulation. Antipsychotic drugs are the most common offenders, but drug-induced parkinsonism may be seen with many other drugs, such as antiemetics and certain calcium-channel blockers. These medications are widely used in the elderly. Unlike the first generation of antipsychotic drugs, all of which cause parkinsonism and other extrapyramidal side effects, atypical antipsychotics have motor side effects that are not uniform. Among the atypicals, only quetiapine and clozapine are not associated with drug-induced parkinsonism. Since drug-induced parkinsonism is frequently under-recognized, it may be devastating in an elderly person with already compromised gait.

IBZM tool: a fully automated expert system for the evaluation of IBZM SPECT studies

PURPOSE

Visual reading of [(123)I]IBZM SPECT scans depends on the experience of the interpreter. Therefore, semi-quantification of striatal IBZM uptake is commonly considered mandatory. However, semi-quantification is time consuming and prone to error, particularly if the volumes of interest (VOIs) are positioned manually. Therefore, the present paper proposes a new software tool ("IBZM tool") for fully automated and standardised processing, evaluation and documentation of [(123)I]IBZM SPECT scans.

METHODS

The IBZM tool is an easy-to-use SPM toolbox. It includes automated procedures for realignment and summation of multiple frames (motion correction), stereotactic normalisation, scaling, VOI analysis of striatum-to-reference ratio R, classification of R and standardised display. In order to evaluate the tool, which was developed at the University of Hamburg, the tool was transferred to the University of Hannover. There it was applied to 27 well-documented subjects: eight patients with multi-system atrophy (MSA), 12 patients with Parkinson's disease (PD) and seven controls. The IBZM tool was compared with manual VOI analysis.

RESULTS

The sensitivity and specificity of the IBZM tool for the differentiation of the MSA subjects from the controls were 100% and 86%, respectively. The IBZM tool provided improved statistical power compared with manual VOI analysis.

CONCLUSION

The IBZM tool is an expert system for the detection of reduced striatal D(2) availability on [(123)I]IBZM SPECT scans. The standardised documentation supports visual and semi-quantitative evaluation, and it is useful for presenting the findings to the referring physician. The IBZM tool has the potential for widespread use, since it appears to be fairly independent of the performance characteristics of the particular SPECT system used. The tool is available free of charge.

[SPECT with 123I-IBZM: utility in differential diagnosis of degenerative Parkinsonisms and establishment of quantification method]

OBJECTIVES

To assess utility of SPECT with 123I-Iolopride ( 123I-IBZM) in the differential diagnosis of patients with Parkinsonian symptoms and try to establish an adequate quantification method.

MATERIAL AND METHOD

We analyzed a total of 34 patients who underwent a study with 123I-IBZM SPECT. Studies were analyzed qualitatively (visually) and quantitatively, using different quantification methods. We used different sums of slices (2, 3, 4, and 7 slices) with different cortical regions as a reference (frontal and occipital regions). Results were analyzed statistically. The final diagnosis of patients was established by two neurologists, specialized in movement disorders.

RESULTS

Studies were visually assessed as normal in 24 cases and as pathologic in the other 10 cases. Scintigraphic studies had an adequate diagnostic correlation in 33 of the 34 patients. Four of the 8 methods used in the quantification were statistically significant in the differentation between normal and pathological. The use of different cortical brain regions as reference did not improve differentation between normal and pathologic studies. Global quantitative assessment of the studies showed that normal studies had higher values than pathological ones, with important overlapping between both categories.

CONCLUSIONS

123I-IBZM SPECT is an effective diagnostic tool in the establishment of the differential diagnosis in patients with Parkinson's disease and Parkinson-Plus. Quantification of these studies had limited utility since the overlapping of index values between normal and pathological restricts their use in individual cases.

Cinnarizine has an atypical antipsychotic profile in animal models of psychosis

Cinnarizine, a drug known as a calcium channel blocker, is currently used for the treatment of migraine and vertigo. Induction of extrapyramidal signs by cinnarizine has been reported in the elderly, which is related to its moderate antagonistic properties at dopamine D2 receptors, resembling the mechanism of action of most antipsychotic drugs. Despite this effect, cinnarizine has never been tested as a putative antipsychotic drug. Here we evaluate the potential effect of cinnarizine in two pharmacological models of psychosis, namely amphetamine- and MK-801-induced hyperlocomotion, as well as its ability to induce catalepsy. Cinnarizine significantly counteracted MK-801 (0.25 mg/kg) and amphetamine (5mg/kg) locomotor effects at doses as low as 20mg/kg, having no incremental effect at 60 or 180 mg/kg. Regarding side-effects, cinnarizine induced no catalepsy in mice at the effective dose of 20 mg/kg, inducing only mild catalepsy at the doses of 60 and 180 mg/kg. Based on these results and on the antagonist effect of cinnarizine on dopamine D2 receptors, we suggest that it has a potential antipsychotic effect with an atypical profile that should be evaluated clinically.

Atypical antipsychotic profile of flunarizine in animal models

RATIONALE

Flunarizine is known as a calcium channel blocker commonly used in many countries to treat migraine and vertigo. Parkinsonism has been described as one of its side-effects in the elderly, which is in agreement with its recently characterized moderate D2 receptor antagonism.

OBJECTIVES

To perform a pre-clinical evaluation of flunarizine as a potential antipsychotic.

METHODS

We evaluated the action of orally administered flunarizine in mice against hyperlocomotion induced by amphetamine and dizocilpine (MK-801) as pharmacological models of schizophrenia, induction of catalepsy as a measure for extrapyramidal symptoms and impairment induced by dizocilpine on the delayed alternation task for working memory.

RESULTS

Flunarizine robustly inhibited hyperlocomotion induced by both amphetamine and dizocilpine at doses that do not reduce spontaneous locomotion (3-30 mg/kg). Mild catalepsy was observed at 30 mg/kg, being more pronounced at 50 mg/kg and 100 mg/kg. Flunarizine (30 mg/kg) improved dizocilpine-induced impairment on the delayed alternation test.

CONCLUSIONS

These results suggest a profile comparable to atypical antipsychotics. The low cost, good tolerability and long half-life (over 2 weeks) of flunarizine are possible advantages for its use as an atypical antipsychotic. These results warrant clinical trials with flunarizine for the treatment of schizophrenia.

Parkinsonism and other movement disorders in outpatients in chronic use of cinnarizine and flunarizine

The purpose of this study is to determine the prevalence and the patterns of movement disorders (MD) in outpatients submitted to the chronic use of cinnarizine (cz) or flunarizine (fz), and to establish the main risk factors for MD development. Over a period of 3 months, data were collected from outpatients who were chronic users of cz or fz in a municipal health institute. A total of 26 outpatients were included and all of them were submitted to a protocol that included DSM-4 diagnosis criteria for drug-induced movement disorders, parkinsonism (PK) and depression. Parkinsonism was diagnosed in 34% of the patients, PK plus akathisia, PK plus akathisia and bucco-linguo-masticatory syndrome (BLMS), isolated BLMS and dystonia were found in 4% patients each. Patients with BLMS had the highest median age and the longest average period in which they used the drugs. The affected group, when compared to the non-affected one, presented with higher rates of depression. This study demonstrates the existence of a direct relationship between the time of use of cz and fz, the age and the prevalence of PK and other MD. It also suggests that these drugs increase the incidence of depression.

Differential inhibition of T-type calcium channels by neuroleptics

T-type calcium channels play critical roles in cellular excitability and have been implicated in the pathogenesis of a variety of neurological disorders including epilepsy. Although there have been reports that certain neuroleptics that primarily target D2 dopamine receptors and are used to treat psychoses may also interact with T-type Ca channels, there has been no systematic examination of this phenomenon. In the present paper we provide a detailed analysis of the effects of several widely used neuroleptic agents on a family of exogenously expressed neuronal T-type Ca channels (alpha1G, alpha1H, and alpha1I subtypes). Among the neuroleptics tested, the diphenylbutylpiperidines pimozide and penfluridol were the most potent T-type channel blockers with Kd values (approximately 30-50 nm and approximately 70-100 nm, respectively), in the range of their antagonism of the D2 dopamine receptor. In contrast, the butyrophenone haloperidol was approximately 12- to 20-fold less potent at blocking the various T-type Ca channels. The diphenyldiperazine flunarizine was also less potent compared with the diphenylbutylpiperadines and preferentially blocked alpha1G and alpha1I T-type channels compared with alpha1H. The various neuroleptics did not significantly affect T-type channel activation or kinetic properties, although they shifted steady-state inactivation profiles to more negative values, indicating that these agents preferentially bind to channel inactivated states. Overall, our findings indicate that T-type Ca channels are potently blocked by a subset of neuroleptic agents and suggest that the action of these drugs on T-type Ca channels may significantly contribute to their therapeutic efficacy.

Contributions of PET and SPECT to the understanding of the pathophysiology of Parkinson's disease

Positron emission tomography (PET) and single photon emission computed tomography (SPECT) provide the means to studying in vivo the neurochemical, hemodynamic or metabolic consequences of the degeneration of the nigrostriatal dopaminergic system in Parkinson's disease (PD). The extent of striatal dopaminergic denervation can be quantified with radiotracers as [18F]FDopa for PET and [123I]tropanes for SPECT. There are other radiotracers such as [11C]Dopa and meta-tyrosines as well as PET tracers for uptake sites. Striatal uptake of [18F]FDopa and [123I]tropanes is markedly decreased in PD, more in the putamen than in the caudate nucleus, and inversely correlates with the severity of motor signs and with duration of disease. PET and SPECT make possible the assessment by noninvasive means of the changes in dopamine receptor density, the effect of neuronal transplants or neuroprotective treatments in PD patients, or the nigrostriatal dopaminergic function in at-risk subjects. Activation studies using cerebral blood flow and metabolism measurements during a motor task reveal an impaired ability to activate the supplementary motor area and dorsolateral prefrontal cortex in PD. This functional disability is reversed by the use of dopaminergic medication or by surgical treatment by pallidotomy or deep brain stimulation. The differential diagnosis between PD and multiple system atrophy, progressive supranuclear palsy or corticobasal degeneration is not yet clearly established by PET and SPECT, even though these syndromes have some particular neurochemical and metabolic profiles. On the other hand, PET and SPECT are useful for distinguishing PD from Dopa-responsive dystonia, or for assessing the integrity of the nigrostriatal dopaminergic pathway in atypical cases of postural tremor or iatrogenic parkinsonian syndromes.

The Role of Neuroimaging in Development of and Treatment With Antipsychotics

This article addresses how neuroimaging can impact the development of and therapy with antipsychotics. The article explains how drug development, disease pathophysiology and neuroimaging approaches can be understood within a single neurobiological framework. It then highlights the relative strengths and applicability of the two streams of neuroimaging: neurochemical neuroimaging that reveals regional concentrations of particular neurochemical species (receptors, transporters or enzymes) and functional neuroimaging that reveals the effects of drug or disease on regional indices of neuronal function such as blood flow and oxygen and glucose metabolism. The application of these techniques is exemplified with recent examples from development and therapeutic use of antipsychotics. To assist decision making in the context of these imaging possibilities, the article presents an algorithm that can be used to guide decisions regarding the application of neuroimaging in the development of and treatment with antipsychotics.

Imaging of the dopaminergic system in parkinsonism with SPET

Parkinsonism is a feature of various neurodegenerative diseases. Since it is well known that the dopaminergic system plays a major role in parkinsonism, numerous reports have focused on the assessment of the dopaminergic system in vivo. While the use of positron emission tomography (PET) for routine application is still hampered by its limited availability, single photon emission tomography (SPET) has been shown to deliver comparable results to PET in clinical settings. In recent years SPET investigations of the dopamine transporter and of the dopamine D2-like receptors have provided valuable information about the pre- and postsynaptic dopaminergic system in parkinsonism. This article briefly reviews the literature dealing with SPET imaging in parkinsonism and specifically addresses the ligands used, the methodology applied, and the current major clinical applications.

Drug-induced parkinsonism: cinnarizine and flunarizine are potent uncouplers of the vacuolar H+-ATPase in catecholamine storage vesicles

Cinnarizine (1-diphenylmethyl-4-(3-phenyl-2-propenyl)piperazine) and its di-fluorinated derivative flunarizine inhibit the MgATP-dependent generation of a transmembrane proton electrochemical gradient in chromaffin granule ghosts. The concentrations giving 50% inhibition (IC50) of the MgATP-dependent generation of the pH-gradient were 5.9+/-0.6 microM (n = 6) and 3.0+/-0.3 microM (n = 5) for cinnarizine and flunarizine, respectively. The IC50 values for inhibiting the generation of the membrane potential were even lower, i.e. 0.19+/-0.06 microM (n = 6) and 0.15+/-0.01 microM (n = 4) for cinnarizine and flunarizine, respectively. Cinnarizine (10 microM) also inhibited the energy-dependent vesicular uptake of [14C]-dopamine (50 microM) by 76%, i.e. from 2.1+/-0.9 to 0.5+/-0.6 nmol/mg protein/min (n = 5, P < 0.002). Cinnarizine (10 microM) increased the MgATPase activity of the granule ghosts by 47+/-26% (n = 4) compatible with an uncoupling of the vacuolar H+-ATPase activity. The IC50-values observed for the two compounds are in the same range as their reported therapeutic plasma concentrations in vivo, suggesting that cinnarizine and flunarizine may well inhibit proton pumping and catecholamine uptake in storage vesicles also in vivo. This mechanism of action may contribute to the drug-induced parkinsonism seen as a side-effect of the two drugs.

Effects of dotarizine and flunarizine on chromaffin cell viability and cytosolic Ca2+

Dotarizine (a novel piperazine derivative with antimigraine properties) and flunarizine (a Ca2+ channel antagonist) were compared concerning: first, their ability to cause chromaffin cell damage in vitro; second, the possible correlation of their octanol/water partition coefficients and those of another 28 compounds (i.e., Ca2+ channel antagonists, blockers of histamine H1 receptors, antimycotics, beta-adrenoceptor antagonists, neuroleptics), with their ability to cause cell damage; third, their capacity to protect the cells against the damaging effects of veratridine; and fourth, their capabilities to enhance the basal cytosolic Ca2+ concentration in fura-2-loaded single chromaffin cells, or to modify the pattern of [Ca2+]i oscillations elicited by veratridine. After 24-h exposure to 1-30 microM dotarizine, the viability of bovine adrenal chromaffin cells (measured under phase contrast or as lactate dehydrogenase, released into the medium) was similar to that of control, untreated cells; at 100 microM, 80% lactate dehydrogenase release was produced. At 1-3 microM flunarizine caused no cell damage; however 10 microM caused 20% lactate dehydrogenase release and 30 and 100 microM over 90% lactate dehydrogenase release. The time course of cell damage was considerably faster for flunarizine, in comparison to dotarizine. Out of 30 molecules tested (at 10 microM), having different octanol/water partition coefficients (log P), dotarizine was among the molecules causing no cell damage; flunarizine caused 20% cell loss, lidoflazine and verapamil over 50% cell loss, and penfluridol, draflazine, astemizole or nifedipine over 80% cell loss. No correlation was found between log P and cytotoxicity. Both dotarizine (10-30 microM) and flunarizine (3-10 microM) provided protection against veratridine-induced cell death; however, at 30 microM dotarizine afforded a pronounced protection while flunarizine enhanced the cytotoxic effects of veratridine. Dotarizine (30 microM) (but not flunarizine) caused a prompt transient elevation of the basal [Ca2+]i. Both compounds abolished the K+-induced increases of [Ca2+]i as well as the oscillations of [Ca2+]i induced by veratridine. The blocking effects of dotarizine were readily reversed after washout, while those of flunarizine were long-lasting. These differences might be relevant to the clinical use of dotarizine as an antimigraine drug.

Does the antimigraine action of flunarizine involve the dopaminergic system? A clinical-neuroendocrinological study

We have investigated the prolactin response to bromocriptine (BRC), a D2 dopamine receptor agonist in migrainous women before and after treatment with flunarizine. We evaluated whether this test was predictive of therapeutic efficacy of flunarizine treatment and whether the therapeutic response to flunarizine treatment was related to its effect on dopaminergic system at tuberoinfundibular level. Ten migrainous women underwent a BRC test in the late follicular phase before and after 1 and 3 months of treatment with flunarizine 10 mg at bedtime. Blood samples of prolactin (PRL), growth hormone, follicle-stimulating hormone, luteinizing hormone, estradiol and progesterone were taken at basal condition. PRL was also evaluated 1 and 2 h after BRC (2.5 mg) administration. Each patient kept a daily headache diary for 1 month prior to the test and throughout the study. The level of PRL inhibition after BRC administration, observed before flunarizine treatment, was not predictive of the therapeutic response observed after 1 and 3 months of treatment. The effect of flunarizine on PRL level was not related to the therapeutic efficacy of the drug. These data suggest that flunarizine does not attenuate the activity of dopaminergic neurons in migrainous patients, and that the antimigraine effect of flunarizine does not seem related to its action on dopaminergic system at least at tuberoinfundibular level.

Long-term effect of a single dose of flunarizine in Huntington's disease

We report a preliminary pilot study on the clinical efficacy of flunarizine (FNZ), a calcium-entry blocker that causes extrapyramidal side-effects, in 10 patients with Huntington's disease (HD). FNZ (20 mg) administered by the sublingual route resulted in a decrease in choreic movements and improved dexterity in performing several tests. These effects lasted for at least 7 days after a single dose. Therefore, FNZ seems to exert the same effect as a long-acting neuroleptic agent in our HD patients.Copyright Lippincott-Raven Publishers

Verapamil for severe hyperkinetic movement disorders

The use of verapamil in three cases of severe hyperkinetic movement disorders resulted in dramatic improvement in patients who had been refractory to many other treatments over a prolonged period. A videotape illustration of one of the patients is provided. The mechanism of action and evidence of efficacy of calcium-channel blockers for abnormal movements are discussed.

Imaging the pre- and postsynaptic side of striatal dopaminergic synapses in idiopathic cervical dystonia: a SPECT study using [123I] epidepride and [123I] beta-CIT

There is increasing evidence that a dysfunction of the dopaminergic system may be involved in the pathogenesis of idiopathic dystonia. To visualize possible alterations of the pre- and postsynaptic side of striatal dopaminergic synapses, SPECT studies using the radiotracers [123I] epidepride and [123I] beta-CIT were performed in 10 patients with idiopathic cervical dystonia. Eleven age- and sex-matched subjects served as controls. [123I] Epidepride is a new highly affine marker of D2 receptors, and [123I] beta-CIT binds to dopamine transporters on dopaminergic nerve endings. [123I] Epidepride binding was significantly reduced in both striata of dystonia patients compared with controls (p < 0.05). In contrast, striatal [123I beta-CIT uptake did not differ from controls. We conclude that dopaminergic dysfunction in idiopathic focal dystonia mainly involves postsynaptic mechanisms and suggest a disturbance of the indirect pathway of the motor circuit resulting in a disinhibited thalamocortical stimulation.