Norepinephrine precursor therapy in neurogenic orthostatic hypotension

Efficacy, safety, and response predictors of Astragalus in patients with mild to moderate Alzheimer's disease: A study protocol of an assessor-blind, statistician-blind open-label randomized controlled trial

Background

This pragmatic clinical trial aims to determine the efficacy and safety of add-on Astragalus membranaceus (AM) for cognition and non-cognition in patients with of mild to moderate Alzheimer's disease complicated with orthostatic hypotension in orthostatic hypotension, elucidate the underlying mechanisms, identify related response predictors, and explore effective drug components.

Methods

This is an add-on, assessor-blinded, parallel, pragmatic, randomized controlled trial. At least 66 adults with mild to moderate Alzheimer's disease (AD) and OH aged 50-85 years will be recruited. Participants will be randomized in a 1:1:1 ratio to receive 24 weeks of routine care or add-on low dose AM or add-on high dose AM group. The primary efficacy outcome will be measured by the Alzheimer's Disease Assessment Scale-Cognitive Subscale, Chinese version. Secondary efficacy outcome assessment will include neuropsychological tests, blood pressure, plasma biomarkers, multimodal electroencephalograms, and neuroimaging. Safety outcome measures will include physical examinations, vital signs, electrocardiography, laboratory tests (such as hematologic and blood chemical tests), and adverse event records.

Ethics and dissemination

This trial was approved and supervised by Fujian Medical University Union Hospital (2021KJCX040). Independent results, findings will be published in peer-reviewed journals and presented at national and international conferences.

Trial registration number

NCT05647473; ClinicalTrials.gov Identifier.

Hypotension with neurovascular changes and cognitive dysfunction: An epidemiological, pathobiological, and treatment review

ABSTRACT

Hypotension is a leading cause of age-related cognitive impairment. The available literature evidences that vascular factors are associated with dementia and that hypotension alters cerebral perfusion flow and can aggravate the neurodegeneration of Alzheimer's disease (AD). Despite the discovery of biomarkers and the recent progress made in neurovascular biology, epidemiology, and brain imaging, some key issues remain largely unresolved: the potential mechanisms underlying the neural deterioration observed in AD, the effect of cerebrovascular alterations on cognitive deficits, and the positive effects of hypotension treatment on cognition. Therefore, further well-designed studies are needed to unravel the potential association between hypotension and cognitive dysfunction and reveal the potential benefits of hypotension treatment for AD patients. Here, we review the current epidemiological, pathobiological, and treatment-related literature on neurovascular changes and hypotension-related cognitive dysfunction and highlight the unsettled but imminent issues that warrant future research endeavors.

Orthostatic hypotension and neurocognitive disorders in older women: Results from the EPIDOS cohort study

BACKGROUND

Although it is well-admitted that cardiovascular health affects cognition, the association between orthostatic hypotension (OH) and cognition remains unclear. The objectives of the present study were i) to determine among the EPIDOS cohort (EPIdémiologie de l'OStéoporose) whether OH was cross-sectionally associated with cognitive impairment at baseline, and ii) whether baseline OH could predict incident cognitive decline after 7 years of follow-up.

METHODS

Systolic and Diastolic Blood Pressure (SBP and DBP) changes while standing (ie, ΔSBP and ΔDBP, in %) were measured at baseline among 2,715 community-dwelling older women aged 75 years and older using no antihypertensive drugs from the French EPIDOS cohort. OH was defined as a decrease in SBP ≥20 mmHg and/or a decrease in DBP ≥10 mmHg within 3 min after standing. Cognitive impairment was defined as a Short Portable Mental Status Questionnaire (SPMSQ) score <8 (/10). Among those without cognitive impairment at baseline, a possible incident onset of cognitive decline was then sought after 7 years of follow-up among 257 participants.

RESULTS

Baseline ΔSBP was associated with baseline cognitive impairment (adjusted OR = 1.01, p = 0.047), but not with incident onset of cognitive decline after 7 years (adjusted OR = 0.98, p = 0.371). Neither baseline OH nor baseline ΔDBP were associated with cognitive impairment neither at baseline (p = 0.426 and p = 0.325 respectively) nor after 7 years (p = 0.180 and p = 0.345 respectively).

CONCLUSIONS

SBP drop while standing, but neither OH per se nor DBP drop while standing, was associated with baseline cognitive impairment in older women. The relationship between OH and cognitive impairment appears more complex than previously expected.

Droxidopa in the Management of Hepatorenal Syndrome

PURPOSE

Hepatorenal syndrome (HRS) is renal dysfunction associated with the hemodynamic consequences of advanced liver disease and cirrhosis. HRS is associated with a high mortality, and there remain high failure rates with first-line therapy aimed at improving perfusion. We report the use of droxidopa, an oral norepinephrine precursor, to aid in the management of HRS-AKI refractory to first-line therapy.

SUMMARY

A 51-year-old Caucasian male with alcohol-related cirrhosis presented with 1-week history of pre-syncope and falls. He was found to have acute kidney injury meeting diagnostic criteria of HRS based on absence of identifiable contributing factors. After no response to volume expansion, medical management was initiated with midodrine and octreotide and eventually escalated to norepinephrine intravenous infusion. The patient's renal function and urine output improved initially on norepinephrine, but worsened when attempting to wean to a suitable outpatient regimen, becoming dependent upon norepinephrine. On day 13 of hospitalization, droxidopa was initiated at a dose of 100 mg three times daily and titrated to a dose of 400 mg three times daily. Norepinephrine infusion was weaned and discontinued on day 16 of hospitalization. The patient remained hemodynamically stable and was able to be discharged on droxidopa 400 mg three times daily, midodrine 20 mg three times day, and octreotide 200 mcg three times daily.

CONCLUSION

Droxidopa, an oral norepinephrine precursor, presents a novel adjunctive agent for management of HRS refractory to first-line medical management.

Orthostatic Hypotension: Management of a Complex, But Common, Medical Problem

Orthostatic hypotension (OH), a common, often overlooked, disorder with many causes, is associated with debilitating symptoms, falls, syncope, cognitive impairment, and risk of death. Chronic OH, a cardinal sign of autonomic dysfunction, increases with advancing age and is commonly associated with neurodegenerative and autoimmune diseases, diabetes, hypertension, heart failure, and kidney failure. Management typically involves a multidisciplinary, patient-centered, approach to arrive at an appropriate underlying diagnosis that is causing OH, treating accompanying conditions, and providing individually tailored pharmacological and nonpharmacological treatment. We propose a novel streamlined pathophysiological classification of OH; review the relationship between the cardiovascular disease continuum and OH; discuss OH-mediated end-organ damage; provide diagnostic and therapeutic algorithms to guide clinical decision making and patient care; identify current gaps in knowledge and try to define future research directions. Using a case-based learning approach, specific clinical scenarios are presented highlighting various presentations of OH to provide a practical guide to evaluate and manage patients who have OH.

Management of Orthostatic Hypotension in Parkinson's Disease

Orthostatic hypotension (OH) is a common non-motor feature of Parkinson's disease that may cause unexplained falls, syncope, lightheadedness, cognitive impairment, dyspnea, fatigue, blurred vision, shoulder, neck, or low-back pain upon standing. Blood pressure (BP) measurements supine and after 3 minutes upon standing screen for OH at bedside. The medical history and cardiovascular autonomic function tests ultimately distinguish neurogenic OH, which is due to impaired sympathetic nerve activity, from non-neurogenic causes of OH, such as hypovolemia and BP lowering drugs. The correction of non-neurogenic causes and exacerbating factors, lifestyle changes and non-pharmacological measures are the cornerstone of OH treatment. If these measures fail, pharmacological interventions (sympathomimetic agents and/or fludrocortisone) should be introduced stepwise depending on the severity of symptoms. About 50% of patients with neurogenic OH also suffer from supine and nocturnal hypertension, which should be monitored for with in-office, home and 24 h-ambulatory BP measurements. Behavioral measures help prevent supine hypertension, which is eventually treated with non-pharmacological measures and bedtime administration of short-acting anti-hypertensive drugs in severe cases. If left untreated, OH impacts on activity of daily living and increases the risk of syncope and falls. Supine hypertension is asymptomatic, but often limits an effective treatment of OH, increases the risk of hypertensive emergencies and, combined with OH, facilitates end-organ damage. A timely management of both OH and supine hypertension ameliorates quality of life and prevents short and long-term complications in patients with Parkinson's disease.

Droxidopa Persistence in Neurogenic Orthostatic Hypotension May Be Affected by Titration Approach

Droxidopa is approved for the treatment of neurogenic orthostatic hypotension (nOH) symptoms and requires patients to be titrated to individualized effective doses (100–600 mg, three times daily) based on symptomatic response. As per the product label, droxidopa should be titrated every 24–48 hours to an optimum maintenance dose (maximum daily dosage 1,800 mg). In an examination of patients with nOH treated in clinical practice settings (n=4,506) using data from the central Northera specialty-pharmacy hub, titration schedules, daily titration dosage (ie, dosage during first dispensation, the assumed titration period), and daily maintenance dosage (dosage during subsequent dispensations) were characterized. It was found that customized titration schedules (ie, different from the product-label recommendation) had been used in 53% of patients, and these patients had had an average daily titration dosage of 567 mg. In contrast, patients who were titrated as per the label schedule (48 hours, 37%; 24 hours, 10%) had daily titration dosages of 1,500–1,650 mg. A relationship between treatment persistence (measured by number of refills) and maintenance dosage was identified. Average daily maintenance doses in patients who received 2, 3–6, 7–24, and >25 dispensations were 938, 969, 1,069, and 1,167 mg, respectively (P<0.0001). In summary, our data suggest that more than half the patients treated with droxidopa in clinical practice settings are not titrated using the schedule recommended on the product label (ie, not 24–48 hours), and as a result receive lower daily dosages of droxidopa than those treated using the recommended titration schedules. Lower daily maintenance dosages of droxidopa were associated with shorter treatment persistence (ie, fewer dispensations). Reasons for discontinuation could not be examined in this study, but further investigation of these persistence data is warranted.

Management Strategies for Comorbid Supine Hypertension in Patients with Neurogenic Orthostatic Hypotension

PURPOSE OF REVIEW

In autonomic failure, neurogenic orthostatic hypotension (nOH) and neurogenic supine hypertension (nSH) are interrelated conditions characterized by postural blood pressure (BP) dysregulation. nOH results in a sustained BP drop upon standing, which can lead to symptoms that include lightheadedness, orthostatic dizziness, presyncope, and syncope. nSH is characterized by elevated BP when supine and, although often asymptomatic, may increase long-term cardiovascular and cerebrovascular risk. This article reviews the pathophysiology and clinical characteristics of nOH and nSH, and describes the management of patients with both nOH and nSH.

RECENT FINDINGS

Pressor medications required to treat the symptoms of nOH also increase the risk of nSH. Because nOH and nSH are hemodynamically opposed, therapies to treat one condition may exacerbate the other. The management of patients with nOH who also have nSH can be challenging and requires an individualized approach to balance the short- and long-term risks associated with these conditions. Approaches to manage neurogenic BP dysregulation include nonpharmacologic approaches and pharmacologic treatments. A stepwise treatment approach is presented to help guide neurologists in managing patients with both nOH and nSH.

Chemotherapy and Radiation-Associated Cardiac Autonomic Dysfunction

PURPOSE OF REVIEW

Cardiovascular autonomic dysfunction (AD) among cancer survivors is increasingly being recognized. However, the mechanisms and incidence are poorly understood. In this review, the clinical features, diagnostic modalities, proposed mechanisms, and currently available treatments of cardiovascular AD in cancer survivors are described.

RECENT FINDINGS

Much of our current understanding of cardiovascular AD is based on disease states such as diabetes, multisystem atrophy, and Parkinson's disease. Several non-invasive tests, measurements, and scoring systems have been developed as surrogates for autonomic function, with some even demonstrating associations with all-cause mortality. The mechanism of cardiovascular AD specifically in the cancer population, however, has not been directly studied. The etiology of cardiovascular AD in cancer survivors is likely multifactorial, and proposed mechanisms include direct nerve damage by chemoradiation, the pro-inflammatory state associated with malignancy, and paraneoplastic syndromes. It may also be that cardiovascular AD is an early marker of global cardiomyopathy rather than its own condition. Current pharmacologic options for cardiovascular AD are extrapolated from how it has been treated in other disease processes, and these agents have not been studied in the cancer population or compared head-to-head. Cardiovascular AD in cancer survivors can cause significant debilitation and may be associated with all-cause mortality. Current diagnostic modalities have several limitations, such as standardization and validity. However, given the nonspecific nature of cardiovascular AD, these tools provide an objective marker for diagnosis and tracking treatment response. While the mechanism of cardiovascular AD in cancer survivors has not been directly studied, it may be useful to evoke mechanisms of cardiovascular AD in other disease states such as diabetes, Parkinson's disease, and multisystem atrophy in addition to identifying unique conditions associated with malignancy like a pro-inflammatory state. Until further studies are performed, management of cardiovascular AD as seen in other disease states may serve as a guide for symptom management in cancer survivors.

Management of Orthostatic Hypotension

PURPOSE OF REVIEW

This article reviews the management of orthostatic hypotension with emphasis on neurogenic orthostatic hypotension.

RECENT FINDINGS

Establishing whether the cause of orthostatic hypotension is a pathologic lesion in sympathetic neurons (ie, neurogenic orthostatic hypotension) or secondary to other medical causes (ie, non-neurogenic orthostatic hypotension) can be achieved by measuring blood pressure and heart rate at the bedside. Whereas fludrocortisone has been extensively used as first-line treatment in the past, it is associated with adverse events including renal and cardiac failure and increased risk of all-cause hospitalization. Distinguishing whether neurogenic orthostatic hypotension is caused by central or peripheral dysfunction has therapeutic implications. Patients with peripheral sympathetic denervation respond better to norepinephrine agonists/precursors such as droxidopa, whereas patients with central autonomic dysfunction respond better to norepinephrine reuptake inhibitors.

SUMMARY

Management of orthostatic hypotension is aimed at improving quality of life and reducing symptoms rather than at normalizing blood pressure. Nonpharmacologic measures are the key to success. Pharmacologic options include volume expansion with fludrocortisone and sympathetic enhancement with midodrine, droxidopa, and norepinephrine reuptake inhibitors. Neurogenic supine hypertension complicates management of orthostatic hypotension and is primarily ameliorated by avoiding the supine position and sleeping with the head of the bed elevated.

Drug-Related Orthostatic Hypotension: Beyond Anti-Hypertensive Medications

Orthostatic hypotension (OH) is an abnormal blood pressure response to standing, which is associated with an increased risk of adverse outcomes such as syncope, falls, cognitive impairment, and mortality. Medical therapy is one the most common causes of OH, since numerous cardiovascular and psychoactive medications may interfere with the blood pressure response to standing, leading to drug-related OH. Additionally, hypotensive medications frequently overlap with other OH risk factors (e.g., advanced age, neurogenic autonomic dysfunction, and comorbidities), thus increasing the risk of symptoms and complications. Consequently, a medication review is recommended as a first-line approach in the diagnostic and therapeutic work-up of OH, with a view to minimizing the risk of drug-related orthostatic blood pressure impairment. If symptoms persist after the review of hypotensive medications, despite adherence to non-pharmacological interventions, specific drug treatment for OH can be considered. In this narrative review we present an overview of drugs acting on the cardiovascular and central nervous system that may potentially impair the orthostatic blood pressure response and we provide practical suggestions that may be helpful to guide medical therapy optimization in patients with OH. In addition, we summarize the available strategies for drug treatment of OH in patients with persistent symptoms despite non-pharmacological interventions.

Clinical Trials for Neurogenic Orthostatic Hypotension: A Comprehensive Review of Endpoints, Pitfalls, and Challenges

Neurogenic orthostatic hypotension (nOH) is among the most debilitating nonmotor features of patients with Parkinson's disease (PD) and other synucleinopathies. Patients with PD and nOH generate more hospitalizations, make more emergency room visits, create more telephone calls/mails to doctors, and have earlier mortality than those with PD but without nOH. Overall, the health-related cost in patients with PD and OH is 2.5-fold higher compared with patients with PD without OH. Hence, developing effective therapies for nOH should be a research priority. In the last few decades, improved understanding of the pathophysiology of nOH has led to the identification of therapeutic targets and the development and approval of two drugs, midodrine and droxidopa. More effective and safer therapies, however, are still needed, particularly agents that could selectively increase blood pressure only in the standing position because supine hypertension is the main limitation of available drugs. Here we review the design and conduct of nOH clinical trials in patients with PD and other synucleinopathies, summarize the results of the most recently completed and ongoing trials, and discuss challenges, bottlenecks, and potential remedies.

Neurogenic Orthostatic Hypotension: State of the Art and Therapeutic Strategies

Neurogenic orthostatic hypotension (nOH) is a subtype of orthostatic hypotension in which patients have impaired regulation of standing blood pressure due to autonomic dysfunction. Several primary and secondary causes of this disease exist. Patients may present with an array of symptoms making diagnosis difficult. This review article addresses the epidemiology, pathophysiology, causes, clinical features, and management of nOH. We highlight various pharmacological and non-pharmacological approaches to treatment, and review the recent guidelines and our approach to nOH.

Pharmacologic treatment of orthostatic hypotension

Neurogenic orthostatic hypotension (OH) is a disabling disorder caused by impairment of the normal autonomic compensatory mechanisms that maintain upright blood pressure. Nonpharmacologic treatment is always the first step in the management of this condition, but a considerable number of patients will require pharmacologic therapies. Denervation hypersensitivity and impairment of baroreflex buffering makes these patients sensitive to small doses of pressor agents. Understanding the underlying pathophysiology can help in selecting between treatment options. In general, patients with low "sympathetic reserve", i.e., those with peripheral noradrenergic degeneration (pure autonomic failure, Parkinson's disease) and low plasma norepinephrine, tend to respond better to "norepinephrine replacers" (midodrine and droxidopa). On the other hand, patients with relatively preserved "sympathetic reserve", i.e., those with impaired central autonomic pathways but spared peripheral noradrenergic fibers (multiple system atrophy) and normal or slightly reduced plasma norepinephrine, tend to respond better to "norepinephrine enhancers" (pyridostigmine, atomoxetine, and yohimbine). There is, however, a spectrum of responses within these extremes, and treatment should be individualized. Other nonspecific treatments include fludrocortisone and octreotide. The presence of associated clinical conditions, such as supine hypertension, heart failure, postprandial hypotension, PD, MSA, and diabetes need to be considered in the pharmacologic management of these patients.

Addressing Orthostatic Hypotension in Heart Failure: Pathophysiology, Clinical Implications and Perspectives

Heart failure (HF)is a condition at high risk for orthostatic hypotension (OH)given the large proportion of patients at an advanced age and high burden of comorbidities contributing to OH, as well as a high prevalence of medications with neurovascular and volume modulating properties. Early identification of OH in HF seems to be crucial as OH can have an impact on patient symptoms, activity level and independence, be a marker of specific pathophysiological changes or be an indicator of need for personalized treatment. OH might contribute significantly to bad enough prognosis in HF, as, besides a risk of falls and cognitive decline, it was found to be associated with cardiovascular morbidity and mortality. In this review, we aimed to incentivize the routine use of orthostatic testing in HF, as well as stimulate future research in this field, which could lead to significant advances in the treatment and outcomes.

Carbidopa for Afferent Baroreflex Failure in Familial Dysautonomia: A Double-Blind Randomized Crossover Clinical Trial

Afferent lesions of the arterial baroreflex occur in familial dysautonomia. This leads to excessive blood pressure variability with falls and frequent surges that damage the organs. These hypertensive surges are the result of excess peripheral catecholamine release and have no adequate treatment. Carbidopa is a selective DOPA-decarboxylase inhibitor that suppresses catecholamines production outside the brain. To learn whether carbidopa can inhibit catecholamine-induced hypertensive surges in patients with severe afferent baroreflex failure, we conducted a double-blind randomized crossover trial in which patients with familial dysautonomia received high dose carbidopa (600 mg/day), low-dose carbidopa (300 mg/day), or matching placebo in 3 4-week treatment periods. Among the 22 patients enrolled (13 females/8 males), the median age was 26 (range, 12-59 years). At enrollment, patients had hypertensive peaks to 164/116 (range, 144/92 to 213/150 mm Hg). Twenty-four hour urinary norepinephrine excretion, a marker of peripheral catecholamine release, was significantly suppressed on both high dose and low dose carbidopa, compared with placebo (P=0.0075). The 2 co-primary end points of the trial were met. The SD of systolic BP variability was reduced at both carbidopa doses (low dose: 17±4; high dose: 18±5 mm Hg) compared with placebo (23±7 mm Hg; P=0.0013), and there was a significant reduction in the systolic BP peaks on active treatment (P=0.0015). High- and low-dose carbidopa were similarly effective and well tolerated. This study provides class Ib evidence that carbidopa can reduce blood pressure variability in patients with congenital afferent baroreflex failure. Similar beneficial effects are observed in patients with acquired baroreflex lesions.

Cardiovascular Safety Considerations in the Treatment of Neurogenic Orthostatic Hypotension

Neurogenic orthostatic hypotension (nOH), a drop in blood pressure upon standing resulting from autonomic malfunction, may cause debilitating symptoms that can affect independence in daily activities and quality-of-life. nOH may also be associated with cardiovascular comorbidities (e.g., supine hypertension, heart failure, diabetes, and arrhythmias), making treatment decisions complicated and requiring management that should be based on a patient's cardiovascular profile. Additionally, drugs used to treat the cardiovascular disorders (e.g., vasodilators, β-blockers) can exacerbate nOH and concomitant symptoms. When orthostatic symptoms are severe and not effectively managed with nonpharmacologic strategies (e.g., water ingestion, abdominal compression), droxidopa or midodrine may be effective. Droxidopa may be less likely than midodrine to exacerbate supine hypertension, based on conclusions of a limited meta-analysis. In conclusion, treating nOH in patients with cardiovascular conditions requires a balance between symptom relief and minimizing adverse outcomes.

Multiple system atrophy

Multiple system atrophy (MSA) is a sporadic, adult-onset, relentlessly progressive neurodegenerative disorder, clinically characterized by various combinations of autonomic failure, parkinsonism and ataxia. The neuropathological hallmark of MSA are glial cytoplasmic inclusions consisting of misfolded α-synuclein. Selective atrophy and neuronal loss in striatonigral and olivopontocerebellar systems underlie the division into two main motor phenotypes of MSA-parkinsonian type and MSA-cerebellar type. Isolated autonomic failure and REM sleep behavior disorder are common premotor features of MSA. Beyond the core clinical symptoms, MSA manifests with a number of non-motor and motor features. Red flags highly specific for MSA may provide clues for a correct diagnosis, but in general the diagnostic accuracy of the second consensus criteria is suboptimal, particularly in early disease stages. In this chapter, the authors discuss the historical milestones, etiopathogenesis, neuropathological findings, clinical features, red flags, differential diagnosis, diagnostic criteria, imaging and other biomarkers, current treatment, unmet needs and future treatments for MSA.

Orthostatic Hypotension in Parkinson Disease

Orthostatic hypotension (OH) is a sustained fall in blood pressure on standing that can cause symptoms of organ hypoperfusion. OH is associated with increased morbidity and mortality and leads to a significant number of hospital admissions. OH can be caused by volume depletion, blood loss, cardiac pump failure, large varicose veins, medications, or defective activation of sympathetic nerves and reduced norepinephrine release upon standing. Neurogenic OH is a frequent and disabling problem in patients with synucleinopathies such as Parkinson disease, multiple system atrophy, and pure autonomic failure, and it is commonly associated with supine hypertension. Several therapeutic options are available.

Alpha-Synuclein Deposition Within Sympathetic Noradrenergic Neurons Is Associated With Myocardial Noradrenergic Deficiency in Neurogenic Orthostatic Hypotension

Lewy body diseases involve neurogenic orthostatic hypotension (nOH), cardiac noradrenergic deficiency, and deposition of the protein AS (alpha-synuclein) in sympathetic ganglion tissue. Mechanisms linking these abnormalities are poorly understood. One link may be AS deposition within sympathetic neurons. We validated methodology to quantify AS colocalization with TH (tyrosine hydroxylase), a marker of sympathetic noradrenergic innervation, and assessed associations of AS/TH colocalization with myocardial norepinephrine content and cardiac sympathetic neuroimaging data in nOH. Postmortem sympathetic ganglionic AS/TH colocalization indices and myocardial norepinephrine contents were measured in 4 Lewy body and 3 rare non-Lewy body nOH patients. Sixteen Lewy body and 11 non-Lewy body nOH patients underwent in vivo skin biopsies and thoracic 18F-dopamine positron emission tomographic scanning, with cutaneous colocalization indices expressed versus cardiac 18F-dopamine-derived radioactivity. Ganglionic AS/TH colocalization indices were higher and myocardial norepinephrine lower in Lewy body than non-Lewy body nOH ( P=0.0020, P=0.014). The Lewy body nOH group had higher AS/TH colocalization indices in skin biopsies and lower myocardial 18F-dopamine-derived radioactivity than did the non-Lewy body nOH group ( P<0.0001 each). All Lewy body nOH patients had colocalization indices >1.5 in skin biopsies and 18F-dopamine-derived radioactivity <6000 nCi-kg/cc-mCi, a combination not seen in non-Lewy body nOH patients ( P<0.0001). In Lewy body nOH, AS deposition in sympathetic noradrenergic nerves is related to postmortem neurochemical and in vivo neuroimaging evidence of myocardial noradrenergic deficiency. These associations raise the possibility that intraneuronal AS deposition plays a pathophysiological role in the myocardial sympathetic neurodegeneration attending Lewy body nOH.

Droxidopa for Hypotension of Different Etiologies: Two Case Reports

Orthostatic hypotension is defined as a decrease in systolic blood pressure of at least 20 mmHg or a decrease in diastolic blood pressure of at least 10 mmHg (or both), within three minutes of moving from a supine to an upright or standing position. Droxidopa is a synthetic amino acid analog that is directly metabolized to norepinephrine by dopa-decarboxylase, subsequently providing alpha and beta-agonist effects to increase blood pressure. It is indicated in the treatment of neurogenic orthostatic hypotension caused by primary autonomic failure that is associated with Parkinson disease, multi-system atrophy, pure autonomic failure, dopamine beta-hydroxylase deficiency, and/or non-diabetic autonomic neuropathy. In addition, it has been studied in other disease states, such as diabetic autonomic neuropathy-associated orthostatic hypotension and supine hypotension. We report on two cases of off-label droxidopa use. The first case was for diabetic autonomic neuropathy-associated orthostatic hypotension, and the second case was for hypotension due to autonomic dysfunction associated with rheumatoid arthritis. Although the outcomes differed in each case, this article contributes to the literature demonstrating that droxidopa may have varying effects in treating orthostatic hypotension of non-neurogenic etiology.

Droxidopa for the treatment of neurogenic orthostatic hypotension in neurodegenerative diseases

INTRODUCTION

L-threo-3,4-dihydroxyphenylserine (droxidopa), a pro-drug metabolized to norepinephrine in nerve endings and other tissues, has been commercially available in Japan since 1989 for treating orthostatic hypotension symptoms in Parkinson's disease (PD) patients with a Hoehn & Yahr stage III rating, as well as patients with Multiple System Atrophy (MSA), familial amyloid polyneuropathy, and hemodialysis. Recently, the FDA has approved its use in symptomatic neurogenic orthostatic hypotension (NOH). Areas covered: The authors review the effects of droxidopa in NOH with a focus on the neurodegenerative diseases PD, MSA, and pure autonomic failure (PAF). Expert opinion: A few small and short placebo-controlled clinical trials in NOH showed significant reductions in the manometric drop in blood pressure (BP) after posture changes or meals. Larger Phase III studies showed conflicting results, with two out of four trials meeting their primary outcome and thus suggesting a positive yet short-lasting effect of the drug on OH Questionnaire composite score, light-headedness/dizziness score, and standing BP during the first two treatment-weeks. Results appear essentially similar in PD, MSA, and PAF. The FDA granted droxidopa approval in the frame of an 'accelerated approval program' provided further studies are conducted to assess its long-term effects on OH symptoms.

Integrated Analysis of Droxidopa for the Treatment of Neurogenic Orthostatic Hypotension in Patients with Parkinson Disease

Introduction

Neurogenic orthostatic hypotension (nOH) is associated with neurodegenerative conditions, may cause symptoms of end-organ hypoperfusion, increases fall risk, and can negatively impact quality of life. Droxidopa is approved for the treatment of symptomatic nOH in adults. As the largest subpopulation of patients with nOH has a diagnosis of Parkinson disease (PD), the efficacy and tolerability of droxidopa in patients with PD and nOH were examined using integrated clinical trial data.

Methods

Post hoc analyses included data from the phase 3, randomized, placebo-controlled clinical trials of droxidopa (two short-term [1-2 weeks] trials and one medium-term [8-10 weeks] trial) in the subset of participants with PD and symptomatic nOH. Efficacy was assessed using standing blood pressure (BP) measurements and the Orthostatic Hypotension Questionnaire (OHQ), a patient-reported evaluation of nOH symptoms (Orthostatic Hypotension Symptom Assessment [OHSA]), and their impact (Orthostatic Hypotension Daily Activity Scale [OHDAS]).

Results

The analysis included 307 patients with PD (droxidopa, n = 150; placebo, n = 157). Compared with placebo, droxidopa significantly improved the OHQ composite score (P = 0.014), the OHSA composite score (P = 0.022), and the OHDAS composite score (P = 0.029) from baseline to end of study/week one. We found significant increases in standing mean systolic/diastolic BP for droxidopa versus placebo (P = 0.003/0.002). Adverse event (AE) rates were qualitatively similar between groups; the most frequently reported AEs in the droxidopa groups included headache, dizziness, nausea, and hypertension.

Conclusions

These post hoc analyses suggest that droxidopa provides meaningful clinical benefits and is well tolerated in the treatment of symptomatic nOH in patients with PD.

Supine plasma NE predicts the pressor response to droxidopa in neurogenic orthostatic hypotension

OBJECTIVE

To test whether the plasma levels of norepinephrine (NE) in patients with neurogenic orthostatic hypotension (nOH) predict their pressor response to droxidopa.

METHODS

This was an observational study, which included patients with nOH. All patients had standardized autonomic function testing including determination of venous plasma catecholamine levels drawn through an indwelling catheter while resting supine. This was followed by a droxidopa titration with 100 mg increments in successive days until relief of symptoms, side effects, or the maximum dose of 600 mg was reached. No response was defined as an increase of <10 mm Hg in systolic blood pressure (BP) after 3-minute standing 1 hour after droxidopa administration. Nonlinear regression models were used to determine the relationship between BP response and plasma NE levels.

RESULTS

We studied 20 patients with nOH due to Parkinson disease, pure autonomic failure, multiple system atrophy, or autoimmune autonomic neuropathies. Their supine plasma NE levels ranged from 44 to 850 pg/mL. Lower supine plasma NE levels were associated with greater pressor effect 1 hour after dose (R² = 0.49) and higher standing BP (R² = 0.45). Patients with no pressor response to droxidopa had higher NE levels (382 ± 100 vs 115 ± 20 pg/mL, p = 0.0014). A supine NE level of <219.5 pg/mL had 83% sensitivity and 93% specificity to predict a pressor response (area under the curve = 0.95, p = 0.0023).

CONCLUSIONS

In patients with nOH, lower supine resting plasma NE levels are associated with a greater pressor effect of droxidopa treatment. This finding should help identify patients with nOH most likely to respond to standard doses of droxidopa.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that lower supine plasma NE levels accurately identify patients with nOH more likely to have a greater pressor effect from droxidopa.

Substantial renal conversion of L-threo-3,4-dihydroxyphenylserine (droxidopa) to norepinephrine in patients with neurogenic orthostatic hypotension

BACKGROUND

The pressor effect of L-threo-3,4-dihydroxyphenylserine (L-DOPS, droxidopa, Northera™) results from conversion of L-DOPS to norepinephrine (NE) in cells expressing L-aromatic-amino-acid decarboxylase (LAAAD). After L-DOPS administration the increase in systemic plasma NE is too small to explain the increase in blood pressure. Renal proximal tubular cells abundantly express LAAAD. Since NE generated locally in the kidneys could contribute to the pressor effect of L-DOPS, in this study we assessed renal conversion of L-DOPS to NE.

METHODS

Ten patients who were taking L-DOPS for symptomatic orthostatic hypotension had blood and urine sampled about 2 h after the last L-DOPS dose. L-DOPS and NE were assayed by alumina extraction followed by liquid chromatography with electrochemical detection. Data were compared in patients off vs. on levodopa/carbidopa.

RESULTS

In patients off levodopa/carbidopa the ratio of NE/L-DOPS in urine averaged 63 times that in plasma (p = 0.0009 by t test applied to log-transformed data). In marked contrast, in the three patients on levodopa/carbidopa the ratio of NE/L-DOPS in urine did not differ from that in plasma.

CONCLUSION

There is extensive renal production of NE from L-DOPS. Carbidopa seems to attenuate the conversion of L-DOPS to NE in the kidneys. Further research is needed to assess whether the proposed paracrine effect of L-DOPS in the kidneys contributes to the systemic pressor response.

Comparison of the Pharmacokinetics of Droxidopa After Dosing in the Fed Versus Fasted State and with 3-Times-Daily Dosing in Healthy Elderly Subjects

Background

Droxidopa is an oral prodrug of norepinephrine approved for the treatment of symptomatic neurogenic orthostatic hypotension. This two-part, randomized, crossover study evaluated the 24-h pharmacokinetic profile of droxidopa in 24 healthy elderly subjects.

Methods

Noncompartmental analysis was used to calculate the area under the plasma concentration–time curve (AUC), maximum plasma concentration (C_max), time of C_max (t_max), and elimination half-life (t_½e) of droxidopa and metabolites. Droxidopa was administered in the fed (high-fat/high-calorie meal) or fasted state either as a single 300-mg dose (three 100-mg capsules) or 3 times/day (TID) (three 100-mg capsules) at 4-h intervals.

Results

Administration of a single droxidopa dose in the fed versus fasted state decreased mean C_max (2057 vs 3160 ng/mL) and mean AUC (10,927 vs 13,857 h × ng/mL) and increased median t_max twofold (4.00 vs 2.00 h). Differences between the fed and fasted state for mean t_½e (2.58 vs 2.68 h) were not observed. Fed versus fasted geometric mean ratios for C_max and AUC were 66% [90% confidence interval (CI) 60.7–71.7] and 80% (90% CI 72.6–88.1), respectively. With TID dosing, similar values for C_max were observed after each dose (range 2789–3389 ng/mL) with no return to baseline between doses. Norepinephrine C_max was 895 pg/mL following dose 1, with no further increases upon subsequent doses; norepinephrine levels remained above baseline for 12–16 h after dose 1.

Conclusions

Absorption of a single dose of droxidopa is slowed after a high-fat/high-calorie meal; for consistent effect, administer droxidopa in the same manner (with or without food). Pharmacokinetic parameters of droxidopa are similar after single and TID dosing.

ClinicalTrials.gov Identifier: NCT01149629.

Roles of catechol neurochemistry in autonomic function testing

Catechols are a class of compounds that contain adjacent hydroxyl groups on a benzene ring. Endogenous catechols in human plasma include the catecholamines norepinephrine, epinephrine (adrenaline), and dopamine; the catecholamine precursor DOPA, 3,4-dihydroxyphenylglycol (DHPG), which is the main neuronal metabolite of norepinephrine; and 3,4-dihydroxyphenylacetic acid (DOPAC), which is the main neuronal metabolite of dopamine. In the diagnostic evaluation of patients with known or suspected dysautonomias, measurement of plasma catechols is rarely diagnostic but often is informative. This review summarizes the roles of clinical catechol neurochemistry in autonomic function testing.

Treatment of autonomic dysfunction in Parkinson disease and other synucleinopathies

Dysfunction of the autonomic nervous system afflicts most patients with Parkinson disease and other synucleinopathies such as dementia with Lewy bodies, multiple system atrophy, and pure autonomic failure, reducing quality of life and increasing mortality. For example, gastrointestinal dysfunction can lead to impaired drug pharmacodynamics causing a worsening in motor symptoms, and neurogenic orthostatic hypotension can cause syncope, falls, and fractures. When recognized, autonomic problems can be treated, sometimes successfully. Discontinuation of potentially causative/aggravating drugs, patient education, and nonpharmacological approaches are useful and should be tried first. Pathophysiology-based pharmacological treatments that have shown efficacy in controlled trials of patients with synucleinopathies have been approved in many countries and are key to an effective management. Here, we review the treatment of autonomic dysfunction in patients with Parkinson disease and other synucleinopathies, summarize the nonpharmacological and current pharmacological therapeutic strategies including recently approved drugs, and provide practical advice and management algorithms for clinicians, with focus on neurogenic orthostatic hypotension, supine hypertension, dysphagia, sialorrhea, gastroparesis, constipation, neurogenic overactive bladder, underactive bladder, and sexual dysfunction. © 2018 International Parkinson and Movement Disorder Society.

Refractory orthostatic hypotension in a patient with a spinal cord injury: Treatment with droxidopa

CONTEXT

Orthostatic hypotension (OH) is a common complication in patients with a spinal cord injury, mainly affecting complete injuries above neurological level T6. It is generally more severe during the acute phase but can remain symptomatic for several years.

FINDINGS

A 65-year-old male with a grade ASIA A post-traumatic cervical spinal cord injury, at neurological level C4, presenting with symptomatic refractory OH. Increased blood pressure (BP) levels and an overall clinical improvement was observed after administering an increasing dose of droxidopa. Treatment was started at a dose of 100 mg twice daily (bid), one to be taken upon rising in the morning and another one in the afternoon, at least three hours before bedtime. According to the patient's symptomatic response, each individual dose was increased by 100 mg at 48-hour intervals. Both increased mean BP levels and a subjective symptomatic improvement were evidenced at a dose of 300 mg bid.

CLINICAL RELEVANCE

Treatment with droxidopa increases BP levels and improves symptoms related to refractory OH using all physical and pharmacological measures available. It could therefore constitute an effective alternative treatment for OH in patients with a spinal cord injury.

Evidence-based treatment of neurogenic orthostatic hypotension and related symptoms

Neurogenic orthostatic hypotension, postprandial hypotension and exercise-induced hypotension are common features of cardiovascular autonomic failure. Despite the serious impact on patient’s quality of life, evidence-based guidelines for non-pharmacological and pharmacological management are lacking at present. Here, we provide a systematic review of the literature on therapeutic options for neurogenic orthostatic hypotension and related symptoms with evidence-based recommendations according to the Grading of Recommendations Assessment, Development and Evaluation (GRADE). Patient’s education and non-pharmacological measures remain essential, with strong recommendation for use of abdominal binders. Based on quality of evidence and safety issues, midodrine and droxidopa reach a strong recommendation level for pharmacological treatment of neurogenic orthostatic hypotension. In selected cases, a range of alternative agents can be considered (fludrocortisone, pyridostigmine, yohimbine, atomoxetine, fluoxetine, ergot alkaloids, ephedrine, phenylpropanolamine, octreotide, indomethacin, ibuprofen, caffeine, methylphenidate and desmopressin), though recommendation strength is weak and quality of evidence is low (atomoxetine, octreotide) or very low (fludrocortisone, pyridostigmine, yohimbine, fluoxetine, ergot alkaloids, ephedrine, phenylpropanolamine, indomethacin, ibuprofen, caffeine, methylphenidate and desmopressin). In case of severe postprandial hypotension, acarbose and octreotide are recommended (strong recommendation, moderate level of evidence). Alternatively, voglibose or caffeine, for which a weak recommendation is available, may be useful.

Impact of the Norepinephrine Prodrug Droxidopa on the QTc Interval in Healthy Individuals

A double‐blind, 4‐period crossover study (NCT01327066) was conducted to assess the effect of the novel norepinephrine prodrug droxidopa on the QT interval in in healthy subjects. Subjects were randomized to receive a single dose of droxidopa 600 mg (maximal dose) and 2000 mg (supratherapeutic dose) compared with the positive control, moxifloxacin 400 mg, and placebo, each separated by a 3‐day washout period. Patients were monitored by continuous Holter monitoring, and electrocardiograms (ECGs) were extracted 0.5–23 hours after dosing. Blood samples for pharmacokinetic analysis were collected before dosing and after ECG data collection. The primary end point was the time‐matched placebo‐adjusted change from baseline in the individually corrected QT (QTcI). The time‐averaged QTcI mean placebo‐corrected changes from baseline for droxidopa 600 and 2000 mg were 0.1 milliseconds (90%CI, ‐0.9 to 1.0 milliseconds) and 0.3 milliseconds (90%CI, ‐0.6 to 1.3 milliseconds), respectively, and 9 milliseconds (90%CI, 8.4–10.3 milliseconds) for moxifloxacin. This study found no effect of either dose of droxidopa on cardiac repolarization using QTcI. Analysis of the pharmacokinetic/pharmacodynamic relationship and cardiac repolarization showed no association with droxidopa exposure. There were no clinically relevant effects of droxidopa on heart rate, atrioventricular conduction, or cardiac depolarization identified. No morphologic ECG changes were observed.

Pure Autonomic Failure

Pure autonomic failure (PAF) is a rare sporadic neurodegenerative autonomic disorder characterized by slowly progressive pan autonomic failure without other features of neurologic dysfunctions. The main clinical symptoms result from neurogenic orthostatic hypotension and urinary and gastrointestinal autonomic dysfunctions. Autonomic failure in PAF is caused by neuronal degeneration of pre- and postganglionic sympathetic and parasympathetic neurons in the thoracic spinal cord and paravertebral autonomic ganglia. The presence of Lewy bodies and α-synuclein deposits in these neural structures suggests that PAF is one of Lewy body synucleinopathies, examples of which include multiple system atrophy, Parkinson disease, and Lewy body disease. There is currently no specific treatment to stop progression in PAF. Management of autonomic symptoms is the mainstay of treatment and includes management of orthostatic hypotension and supine hypertension. The prognosis for survival of PAF is better than for the other synucleinopathies.

Critical appraisal of clinical trials in multiple system atrophy: Toward better quality

Multiple system atrophy (MSA) is a rare neurodegenerative disease of undetermined cause. Although many clinical trials have been conducted, there is still no treatment that cures the disease or slows its progression. We sought to assess the clinical trials, methodology, and quality of reporting of clinical trails conducted in MSA patients. We conducted a systematic review of all trials with at least 1 MSA patient subject to any pharmacological/nonpharmacological interventions. Two independent reviewers evaluated the methodological characteristics and quality of reporting of trials. A total of 60 clinical trials were identified, including 1375 MSA patients. Of the trials, 51% (n = 31) were single-arm studies. A total of 28% (n = 17) had a parallel design, half of which (n = 13) were placebo controlled. Of the studies, 8 (13.3%) were conducted in a multicenter setting, 3 of which were responsible for 49.3% (n = 678) of the total included MSA patients. The description of primary outcomes was unclear in 60% (n = 40) of trials. Only 10 (16.7%) clinical trials clearly described the randomization process. Blinding of the participants, personnel, and outcome assessments were at high risk of bias in the majority of studies. The number of dropouts/withdrawals was high (n = 326, 23.4% among the included patients). Overall, the design and quality of reporting of the reviewed studies is unsatisfactory. The most frequent clinical trials were small and single centered. Inadequate reporting was related to the information on the randomization process, sequence generation, allocation concealment, blinding of participants, and sample size calculations. Although improved during the recent years, methodological quality and trial design need to be optimized to generate more informative results. © 2017 International Parkinson and Movement Disorder Society.

Management of Supine Hypertension Complicating Neurogenic Orthostatic Hypotension

Neurogenic orthostatic hypotension (NOH) can be present in a number of disorders, including synucleinopathies, autoimmune disorders, and various genetic disorders. All are characterized by defective norepinephrine release from sympathetic terminals upon standing, resulting in impaired vasoconstriction. NOH is defined as a drop in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg, or both, within 3 minutes of standing or head up-tilt at a minimum of 60°. However, approximately 50% of patients have associated supine hypertension, which greatly complicates treatment. Supine hypertension not only is a common side effect of many anti-hypotensive agents but is also present in untreated patients, suggesting it is, in part, innate to the pathophysiology of autonomic dysfunction. Pathological mechanisms differ depending on the underlying autonomic disorder. In central neurodegenerative disorders, residual post-ganglionic sympathetic activity is likely the primary mechanism, whereas plasma angiotensin, aldosterone, and inappropriate mineralocorticoid receptor activity may contribute in peripheral autonomic lesions. Baroreflex failure/loss of baroreflex buffering is common to both. More work is required. Clinically, there is much dispute regarding the treatment of supine hypertension when there is a risk of exacerbating orthostatic hypotension. However, given the similar levels of end-organ damage (i.e., heart attack and stroke) seen with transient hypertension, it seems clear that treatment is important. Current therapies for both NOH and supine hypertension include a combination of pharmacological and conservative measures. However, in addition to the current standard of care, protocols may consider 24-h blood pressure monitoring and potential future examination of the peripheral post-ganglionic sympathetic nerves in order to apply individualized adjunct therapies. Finally, no anti-hypertensive agents are currently approved for use in this patient population, and development of novel therapies should focus on short-acting agents, selective to the supine position, that act primarily at night when hypertension is most severe/prolonged.

The Pharmacology of Autonomic Failure: From Hypotension to Hypertension

Primary neurodegenerative autonomic disorders are characterized clinically by loss of autonomic regulation of blood pressure. The clinical picture is dominated by orthostatic hypotension, but supine hypertension is also a significant problem. Autonomic failure can result from impairment of central autonomic pathways (multiple system atrophy) or neurodegeneration of peripheral postganglionic autonomic fibers (pure autonomic failure, Parkinson's disease). Pharmacologic probes such as the ganglionic blocker trimethaphan can help us in the understanding of the underlying pathophysiology and diagnosis of these disorders. Conversely, understanding the pathophysiology is crucial in the development of effective pharmacotherapy for these patients. Autonomic failure patients provide us with an unfortunate but unique research model characterized by loss of baroreflex buffering. This greatly magnifies the effect of stimuli that would not be apparent in normal subjects. An example of this is the discovery of the osmopressor reflex: ingestion of water increases blood pressure by 30-40 mm Hg in autonomic failure patients. Animal studies indicate that the trigger of this reflex is related to hypo-osmolality in the portal circulation involving transient receptor potential vanilloid 4 receptors. Studies in autonomic failure patients have also revealed that angiotensin II can be generated through noncanonical pathways independent of plasma renin activity to contribute to hypertension. Similarly, the mineralocorticoid receptor antagonist eplerenone produces acute hypotensive effects, highlighting the presence of non-nuclear mineralocorticoid receptor pathways. These are examples of careful clinical research that integrates pathophysiology and pharmacology to advance our knowledge of human disease.

Integrated analysis of droxidopa trials for neurogenic orthostatic hypotension

Background

Droxidopa, a prodrug of norepinephrine, was approved for treatment of neurogenic orthostatic hypotension (nOH) due to primary autonomic disorders based on 3 randomized double-blind studies. We performed safety and efficacy analyses of this pooled dataset (n = 460).

Methods

Efficacy was assessed using Orthostatic Hypotension Questionnaire (OHQ) scores (composite and individual items). Safety and tolerability were also examined.

Results

Droxidopa improved virtually all nOH symptom scores compared with placebo, significantly reducing OHQ composite score (−2.68 ± 2.20 vs −1.82 ± 2.34 units; P < 0.001), dizziness/lightheadedness score (−3.0 ± 2.9 vs −1.8 ± 3.1 units; P < 0.001), and 3 of 5 other symptom assessments (visual disturbances, weakness, and fatigue [P ≤ 0.010]). Droxidopa significantly improved 3 of 4 measures of activities of daily living (standing a long time, walking a short time, and walking a long time [P ≤ 0.003]) and significantly increased upright systolic blood pressure (11.5 ± 20.5 vs 4.8 ± 21.0 mmHg for placebo; P < 0.001). Droxidopa was effective in patients using inhibitors of dopa decarboxylase (DDCI; the enzyme that converts droxidopa to norepinephrine), but its efficacy was numerically greater in non-DDCI users. Droxidopa was well-tolerated. Rates of most adverse events were similar between groups. Supine hypertension rates were low, but slightly higher in patients receiving droxidopa (≤7.9% vs ≤4.6% for placebo); patients with severe hypertension at screening were excluded from these studies.

Conclusions

Droxidopa is effective for the treatment of nOH in patients with primary autonomic disorders and is generally well-tolerated. A longer trial is underway to confirm efficacy beyond the ≤2 to 10 - week period assessed in the current trials.

Trial registration

ClinicalTrials.gov identifiers: NCT00782340, first received October 29, 2008; NCT00633880, first received March 5, 2008; and NCT01176240, first received July 30, 2010.

Epidemiology, Diagnosis, and Management of Neurogenic Orthostatic Hypotension

BACKGROUND

Orthostatic hypotension (OH) is a sustained fall in blood pressure on standing which can cause symptoms of organ hypoperfusion. OH is associated with increased morbidity and mortality and leads to a significant number of hospital admissions particularly in the elderly (233 per 100,000 patients over 75 years of age in the US). OH can be due to volume depletion, blood loss, large varicose veins, medications, or due to defective activation of sympathetic nerves and reduced norepinephrine release upon standing (i.e., neurogenic OH).

METHODS AND FINDINGS

Literature review. Neurogenic OH is a frequent and disabling problem in patients with synucleinopathies such as Parkinson disease, multiple system atrophy, and pure autonomic failure, and is commonly associated with supine hypertension. Several pharmacological and non-pharmacological therapeutic options are available.

CONCLUSIONS

Here we review the epidemiology, diagnosis, and management of neurogenic OH, and provide an algorithm for its treatment emphasizing the importance of removing aggravating factors, implementing non-pharmacologic measures, and selecting appropriate pharmacological treatments.

Droxidopa in the Treatment of Postural Orthostatic Tachycardia Syndrome

BACKGROUND

Postural orthostatic tachycardia syndrome (POTS) is a constellation of signs and symptoms that occur when a patient is upright and relieved by recumbence. Currently, no drugs are labeled for the treatment for POTS. Droxidopa is an orally administered amino acid that is converted to norepinephrine and thought to improve both blood pressure and symptoms in patients with orthostatic intolerance.

STUDY QUESTION

To appraise the effect of Droxidopa in a clinical setting in patients with POTS refractory to other forms of treatment.

STUDY DESIGN

A retrospective study of patients with POTS at our Syncope and Autonomic Disorders Center. Three hundred fifty-two patients were screened, 54 of them were prescribed Droxidopa and found to be eligible to include in our study.

MEASURES AND OUTCOME

Symptoms of orthostatic intolerance, side effects of therapy and response to treatment. Statistical analyses were done using SPSS software. Thirty-seven patients were included in data analysis. Patients who failed to follow up, didn't obtain Droxidopa due to insurance and cost concerns, had hypertensive response to therapy or had allergic reaction were excluded from data analysis.

RESULTS

The most frequently reported symptom was dizziness in 91.9% of patients, followed by syncope and fatigue in 70.3% and 67.6% of patients, respectively. Symptoms of dizziness, syncope and fatigue were reported less after treatment; 75.7%, 51.4% and 40.5%, respectively. There was no statistically significant difference in standing or sitting blood pressure before and after treatment. Despite the improvement in some symptoms. Only 27% of patients reported improved quality of life after treatment. Of total, 40.5% of patients stopped the treatment either due to side effects or ineffectiveness.

CONCLUSION

Droxidopa appears to improve some symptoms of orthostatic intolerance in patients with POTS but has diminutive impact on quality of life and blood pressure. Further assessment in large clinical trials is needed to evaluate its efficacy.