Mechanism-based therapy of non-cardiac syncope: a practical guide

The term non-cardiac syncope includes all forms of syncope, in which primary intrinsic cardiac mechanism and non-syncopal transient loss of consciousness can be ruled out. Reflex syncope and orthostatic hypotension are the most frequent aetiologies of non-cardiac syncope. As no specific therapy is effective for all types of non-cardiac syncope, identifying the underlying haemodynamic mechanism is the essential prerequisite for an effective personalized therapy and prevention of syncope recurrences. Indeed, choice of appropriate therapy and its efficacy are largely determined by the syncope mechanism rather than its aetiology and clinical presentation. The two main haemodynamic phenomena leading to non-cardiac syncope include either profound hypotension or extrinsic asystole/pronounced bradycardia, corresponding to two different haemodynamic syncope phenotypes, the hypotensive and bradycardic phenotypes. The choice of therapy-aimed at counteracting hypotension or bradycardia-depends on the given phenotype. Discontinuation of blood pressure-lowering drugs, elastic garments, and blood pressure-elevating agents such as fludrocortisone and midodrine are the most effective therapies in patients with hypotensive phenotype. Cardiac pacing, cardioneuroablation, and drugs preventing bradycardia such as theophylline are the most effective therapies in patients with bradycardic phenotype of extrinsic cause.

Oral midodrine for prophylaxis against post-spinal anesthesia hypotension during hip arthroplasty in elderly population: a randomized controlled trial

BACKGROUND

We aimed to evaluate the efficacy of midodrine as a prophylaxis against post-spinal hypotension in elderly patients undergoing hip arthroplasty.

METHODS

This randomized controlled trial included elderly patients undergoing hip arthroplasty under spinal anesthesia. Ninety minutes before the procedure, patients were randomized to receive either 5-mg midodrine or placebo (metoclopramide). After spinal anesthesia, mean arterial pressure (MAP) and heart rate were monitored every 2 min for 20 min then every 5 min until the end of the procedure. Post-spinal hypotension (MAP < 80% baseline) was treated with 10 mg ephedrine. The primary outcome was intraoperative ephedrine consumption. Secondary outcomes were the incidence of post-spinal hypotension, bradycardia, and hypertension (MAP increased by > 20% of the baseline reading).

RESULTS

We analyzed 29 patients in the midodrine group and 27 in the control group. The intraoperative ephedrine consumption was lower in the midodrine group than in the control group (median [quartiles]: 10 [0, 30] mg versus 30 [20, 43] mg, respectively, P-value: 0.002); and the incidence of intraoperative hypotension was lower in the midodrine group than that in the control group. The incidence of hypertension and bradycardia were comparable between the two groups.

CONCLUSION

The use of 5 mg oral midodrine decreased the vasopressor requirements and incidence of hypotension after spinal anesthesia for hip surgery in elderly patients.

CLINICAL TRIAL REGISTRATION

This study was registered on September 22, 2022 at clinicaltrials.gov registry, NCT05548985, URL: https://classic.

CLINICALTRIALS

gov/ct2/show/NCT05548985 .

Evaluation of Midodrine Utilization in Patients with Cancer and Heart Failure

PURPOSE

The purpose of this study was to evaluate safety and cardiovascular outcomes as well as overall survival of cancer patients with concomitant heart failure (HF) treated with midodrine for hypotension.

METHODS

Adult patients diagnosed with cancer and HF who were treated with midodrine at a tertiary cancer center from 03/2013 to 08/2021 were identified. Demographic and clinical parameters were collected retrospectively.

RESULTS

A total of 85 patients were included with a median age of 68 years (IQR: 60, 74; 33% female and 85% White). Of those, 31% had HFpEF (EF ≥ 50%), 42% HF with mildly reduced EF (HFmrEF; EF 41-49%), and 27% HFrEF (EF ≤ 40%). The most common indication for midodrine use was orthostatic hypotension (49%). Midodrine was continued for at least one month in 57% of the patients. Supine hypertension was the only side effect reported in 6% of patients. No statistically significant changes in NYHA class, guideline-directed medical therapy, cardiac biomarkers (NT-proBNP or troponin T), echocardiographic findings or cardiovascular hospitalizations were observed between patients who continued treatment with midodrine compared to those who stopped using midodrine over a median follow-up of 38 months. In the multivariable cox regression analysis, continuation of midodrine, compared to discontinuation, and use of midodrine for orthostatic hypotension, as opposed to other causes of hypotension, were not associated with an increased risk of mortality (HR 0.41, 95% CI 0.24-0.69, p < .0001; HR 0.34, 95% CI 0.18-0.64, p < .001, respectively). In contrast, elevated creatinine (> 1.3 for males and > 1.1 for females) was associated with an increased risk of mortality (HR 1.83, 95% CI 1.07-3.14). LVEF was not significantly associated with lower or higher risk of mortality.

CONCLUSIONS

In our study, midodrine use in patients with cancer and HF was not associated with significant adverse effects, worse cardiovascular outcomes, or increased risk of mortality. Larger, prospective studies are needed to confirm these findings.

The Use of Midodrine as an Adjunctive Therapy to Liberate Patients from Intravenous Vasopressors: A Systematic Review and Meta-analysis of Randomized Controlled Studies

BACKGROUND

Studies evaluating the role of midodrine as an adjunctive therapy to liberate patients with shock from intravenous (IV) vasopressors have yielded mixed results. The aim of our study was to evaluate the efficacy and safety of midodrine as an adjunctive therapy to liberate patients with shock from IV vasopressors.

METHODS

Electronic searches of the MEDLINE, EMBASE, and Cochrane databases through April 2022 for randomized controlled trials (RCTs) that evaluated the use of midodrine versus control in patients with shock and a low dose of IV vasopressors. The primary outcome was total IV vasopressor time, while the secondary outcomes included time-to-IV vasopressor discontinuation, IV vasopressor restart, intensive care unit (ICU) length of stay (LOS), hospital LOS, and incidence of bradycardia.

RESULTS

The final analysis included four RCTs with a total of 314 patients: 158 in the midodrine group and 156 in the control group, with a weighted mean age of 64 years (54.2% men). There was no significant difference in the total IV vasopressor time between the midodrine and control groups (standardized mean difference [SMD] - 0.53; 95% confidence interval [CI] - 1.38 to 0.32, p = 0.22; I² = 92%). Also, there were no significant differences between the two groups in the time-to-IV vasopressor discontinuation (SMD - 0.05; 95% CI - 0.57 to 0.47, p = 0.09), IV vasopressor restart (19.3 vs. 28.3%; risk ratio [RR] 0.74; 95% 0.25-2.20, p = 0.59), ICU LOS (SMD - 0.49; 95% CI - 1.30 to 0.33, p = 0.24), and hospital LOS (SMD 0.01; 95% CI - 0.27 to 0.29, p = 0.92). However, compared with the control group, the midodrine group had a higher risk of bradycardia (15.3 vs. 2.1% RR 5.56; 95% CI 1.54-20.05, p = 0.01).

CONCLUSIONS

Among patients with vasopressor-dependent shock, midodrine was not associated with early liberation of vasopressor support or shorter ICU or hospital length of stay. Adding midodrine increased the risk of bradycardia. Further large RCTs are needed to better evaluate the efficacy and safety of midodrine in liberating patients from IV vasopressors.

Oral midodrine does not expedite liberation from protracted vasopressor infusions: A case-control study

Vasopressor dependence is a common problem affecting patients in the recovery phase of critical illness, often necessitating intensive care unit (ICU) admission and other interventions which carry associated risks. Midodrine is an orally administered vasopressor which is commonly used off-label to expedite weaning from vasopressor infusions and facilitate discharge from ICU. We performed a single-centre, case-control study to assess whether midodrine accelerated liberation from vasopressor infusions in patients who were vasopressor dependent. Cases were identified at the discretion of treating intensivists and received 20 mg oral midodrine every eight h from enrolment. Controls received placebo. Data on duration and dose of vasopressor infusion, haemodynamics and adverse events were collected. Between 2012 and 2019, 42 controls and 19 cases were recruited. Cases had received vasopressor infusions for a median of 94 h versus 29.3 h for controls, indicating prolonged vasopressor dependence amongst cases. Midodrine use in cases was not associated with faster weaning of intravenous (IV) vasopressors (26 h versus 24 h for controls, P = 0.51), ICU or hospital length of stay after adjustment for confounders. Midodrine did not affect mean heart rate but was associated with bradycardia. This case-control study demonstrates that midodrine has limited efficacy in expediting weaning from vasopressor infusions in patients who have already received relatively prolonged courses of these infusions.

Current approach to the treatment of vasovagal syncope in adults

Vasovagal syncope (VVS) is the most common cause of transient loss of consciousness. Although not associated with mortality, it causes injuries, reduces quality of life, and is associated with anxiety and depression. The European and North American cardiac societies recently published syncope clinical practice guidelines. Most patients with VVS do well after specialist evaluation, reassurance and education. Adequate hydration, increased salt intake when not contraindicated, and careful withdrawal of diuretics and specific hypotension-inducing drugs are a reasonable initial strategy. Physical counterpressure maneuvers might be helpful but can be of limited efficacy in older patients and those with short or no prodromes. Orthostatic training lacks long term efficacy and is troubled by non-compliance. Yoga might be helpful, although the biomedical mechanism is unknown. Almost a third of VVS patients continue to faint despite these conservative measures. Metoprolol was not helpful in a pivotal randomized clinical trial. Fludrocortisone and midodrine significantly reduce syncope recurrences with tolerable side effects, when titrated to target doses. Pacing therapy with specialized sensors appears promising in carefully selected population who have not responded conservative measures. Cardioneuroablation may be helpful but has not been studied in a formal clinical trial.

Stimulation of Alpha-1-Adrenergic Receptor Ameliorates Obesity-Induced Cataracts by Activating Glycolysis and Inhibiting Cataract-Inducing Factors

BACKGROUND

Obesity, the prevalence of which is increasing due to the lack of exercise and increased consumption of Westernized diets, induces various complications, including ophthalmic diseases. For example, obesity is involved in the onset of cataracts.

METHODS

To clarify the effects and mechanisms of midodrine, an α1-adrenergic receptor agonist, in cataracts induced by obesity, we conducted various analytic experiments in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a rat model of obesity.

RESULTS

Midodrine prevented cataract occurrence and improved lens clearance in OLETF rats. In the lenses of OLETF rats treated with midodrine, we observed lower levels of aldose reductase, tumor necrosis factor-α, and sorbitol, but higher levels of hexokinase, 5'-adenosine monophosphate-activated protein kinase-alpha, adenosine 5´-triphosphate, peroxisome proliferator-activated receptordelta, peroxisome proliferator-activated receptor gamma coactivator 1-alpha, superoxide dismutase, and catalase.

CONCLUSION

The ameliorating effects of midodrine on cataracts in the OLETF obesity rat model are exerted via the following three mechanisms: direct inhibition of the biosynthesis of sorbitol, which causes cataracts; reduction of reactive oxygen species and inflammation; and (3) stimulation of normal aerobic glycolysis.

Treatment via oral midodrine in a patient with prolonged hypotension following carotid artery stenting: a case report

Background

Hypotension and bradycardia are common hemodynamic complications following carotid artery stenting in patients with carotid artery stenosis. Intravenous fluid resuscitation and inotropes such as dopamine are conventional treatments for post-carotid artery stenting hypotension. However, in case of resistant hypotension, there is no clear treatment method. In this report, while intravenous fluid and inotropes did not resolve the patient’s hypotension, oral midodrine treated post-carotid artery stenting hypotension.

Case presentation

In this report, we present an 82-year-old Caucasian man complaining of a single episode of unilateral visual loss. The patient had left internal carotid artery stenosis and underwent carotid artery stenting. After the procedure, he developed prolonged post-carotid artery stenting hypotension, which was resistant to intravenous fluids and inotropes but immediately showed a promising response to oral midodrine.

Conclusion

Oral midodrine can be considered in treatment of post-carotid artery stenting hemodynamic complications.

A pilot, feasibility, randomised controlled trial of midodrine as adjunctive vasopressor for low-dose vasopressor-dependent hypotension in intensive care patients: The MAVERIC study

PURPOSE

To assess the feasibility and physiological efficacy of adjunctive midodrine in patients with vasopressor-dependent hypotension.

MATERIALS AND METHODS

This was a pilot, open label, randomised controlled trial. Patients were enrolled from two tertiary intensive care units on low dose intravenous vasopressor therapy for more than 24 h. We randomly assigned patients to receive either adjunctive midodrine (10 mg every 8 h) or usual care. The primary efficacy outcome was time to cessation of intravenous vasopressor therapy. Secondary outcomes included protocol compliance, ICU and hospital length of stay.

RESULTS

We screened 381 patients over 22-months and enrolled 62 (32 in midodrine group, 30 in usual care group). Median time to cessation of vasopressor infusion was 16.5 h for midodrine vs 19 h for usual care (p = 0.22). Time in ICU (50 [25.50, 74.00] hours for midodrine v 59 [38.50, 93.25] hours for usual care, p = 0.14) and hospital length of stay (9 days vs. 7.5 days, p = 0.92) were similar. Protocol compliance was 96.9%. One patient ceased midodrine early due to symptomatic bradycardia.

CONCLUSIONS

Adjunctive midodrine therapy was feasible with acceptable compliance, duration of therapy, and safety profile. However, at the chosen dose, there was no evidence of physiological or clinical efficacy.

Midodrine for the prevention of vasovagal syncope: a systematic review and meta-analysis

AIMS

Vasovagal syncope (VVS) is a common clinical condition that lacks effective medical therapies despite being associated with significant morbidity. Current guidelines suggest that midodrine, a prodrug for an α1-adrenergic receptor agonist, might suppress VVS but supporting studies have utilized heterogeneous methods and yielded inconsistent results. To evaluate the efficacy of midodrine to prevent syncope in patients with recurrent VVS by conducting a systematic review and meta-analysis of published studies.

METHODS AND RESULTS

Relevant randomized controlled trials were identified from the MEDLINE, Embase, CENTRAL, and CINAHL databases without language restriction from inception to June 2021. All studies were conducted in clinical syncope populations and compared the benefit of midodrine vs. placebo or non-pharmacological standard care. Weighted relative risks (RRs) were estimated using random effects meta-analysis techniques. Seven studies (n = 315) met inclusion criteria. Patients were 33 ± 17 years of age and 31% male. Midodrine was found to substantially reduce the likelihood of positive head-up-tilt (HUT) test outcomes [RR = 0.37 (0.23-0.59), P < 0.001]. In contrast, the pooled results of single- and double-blind clinical trials (I2 = 54%) suggested a more modest benefit from midodrine for the prevention of clinical syncope [RR = 0.51 (0.33-0.79), P = 0.003]. The two rigorous double-blind, randomized, placebo-controlled clinical trials included 179 VVS patients with minimal between-study heterogeneity (I2 = 0%) and reported a risk reduction with midodrine [RR = 0.71 (0.53-0.95), P = 0.02].

CONCLUSIONS

Midodrine is effective in preventing syncope induced by HUT testing and less, but still significant, RR reduction in randomized, double-blinded clinical trials.

Midodrine improves clinical and economic outcomes in patients with septic shock: a randomized controlled clinical trial

BACKGROUND

Prolonged use of intravenous (IV) vasopressors in patients with septic shock can lead to deleterious effects.

AIMS

This study assessed the impact of midodrine administration on weaning off IV vasopressors and its economic value.

METHODS

It is a prospective randomized controlled study of 60 resuscitated patients with septic shock who demonstrated clinical stability on low-dose IV vasopressors for at least 24 h. Participants were randomized into two groups: norepinephrine (IV norepinephrine) and midodrine (IV norepinephrine + oral midodrine 10 mg thrice a day). A cost comparison was applied based on the outcomes of both groups.

RESULTS

The median duration of norepinephrine administration in the midodrine and norepinephrine groups was 4 and 6 days, respectively (p = 0.001). Norepinephrine weaning time was significantly less in the midodrine versus norepinephrine groups (26 and 78.5 h, respectively; p < 0.001). Mortality was 43.3% versus 73.3% in the midodrine and norepinephrine groups, respectively (p = 0.018). The mean length of stay was comparable in the two groups. The midodrine group showed cost-saving results versus the norepinephrine group.

CONCLUSION

The use of midodrine in septic shock patients significantly reduced IV norepinephrine duration, weaning period during the septic shock recovery phase, and mortality. Thus, the use of midodrine is dominant with less cost, better outcome and a cost-saving option in terms of budget impact analysis. This study was registered at clinicaltrials.gov (NCT 03,911,817) on April 11, 2019.

Management of Orthostatic Hypotension in the Hospitalized Patient: A Narrative Review

Orthostatic hypotension is a frequent cause of falls and syncope, impairing quality of life. It is an independent risk factor of mortality and a common cause of hospitalizations, which exponentially increases in the geriatric population. We present a management plan based on a systematic literature review and understanding of the underlying pathophysiology and relevant clinical pharmacology. Initial treatment measures include removing offending medications and avoiding large meals. Clinical assessment of the patients' residual sympathetic tone can aid in the selection of initial therapy between norepinephrine "enhancers" or "replacers." Role of splanchnic venous pooling is overlooked, and applying abdominal binders to improve venous return may be effective. The treatment goal is not normalizing upright blood pressure but increasing it above the cerebral autoregulation threshold required to improve symptoms. Hypertension is the most common associated comorbidity, and confining patients to bed while using pressor agents only increases supine blood pressure, leading to worsening pressure diuresis and orthostatic hypotension. Avoiding bedrest deconditioning and using pressors as part of an orthostatic rehab program are crucial in reducing hospital stay.

Use of midodrine and fludrocortisone in neurogenic shock: A case report

Our case report includes a 42 year old male who had C6-C7 fracture dislocation with complete spinal cord injury following a motor vehicle accident. The patient underwent combined anterior and posterior fixation of the cervical spine. However, the patient had hypotension as a part of neurogenic shock and required vasopressor to maintain mean arterial pressure. The patient was treated in Intensive Care Unit with noradrenaline infusion to maintain mean arterial pressure but it was really challenging to stop the vasopressor. The patient was started on oral Midodrine and Fludrocortisone; vasopressor dose was tapered and finally stopped.

Midodrine overdose in children: a case report and review of treatment for hypertensive emergencies

Midodrine is an antihypotensive agent used primarily in the adult population for orthostatic hypotension and reflex syncope, postural orthostatic tachycardia syndrome (POTS), and hemodialysis-induced hypotension. Limited information about midodrine ingestion and overdose exists in children with only a single case series reported in the literature. Varying presentations of midodrine ingestion in children have not been shown to be acutely life-threatening in doses up to 50 mg. We present a case of a 12-year-old who intentionally ingested 100 mg of midodrine and presented with a hypertensive emergency and seizure activity. This is the largest reported dose ingested in a child. The patient was observed and treated with a nicardipine infusion in the pediatric intensive care unit (PICU). Prompt identification and treatment of symptoms contributed to a favorable outcome with no neurologic deficits and complete recovery from an intentional ingestion of midodrine. Mechanism, duration of action, and management of midodrine ingestion including treatment for a hypertensive emergency in children are discussed. Commonly used pharmacologic agents to treat hypertension are reviewed. This case report of a significant ingestion of midodrine reviews management of hypertensive emergencies and provides information and guidance to healthcare professionals unfamiliar with this medication and its potentially fatal effects.

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.

Combination therapy of midodrine and droxidopa for refractory hypotension in heart failure with preserved ejection fraction per a pharmacist's proposal: a case report

Background

Patients with chronic heart failure (CHF) are often treated using many diuretics for symptom relief; however, diuretic use may have to continue despite hypotension development in these patients. Here, we present a case of heart failure with preserved ejection fraction (HFpEF), which is defined as ejection fraction ≥50% in CHF, and refractory hypotension, which was treated with midodrine and droxidopa to normalize blood pressure.

Case presentation

The patient was a 62-year-old man with a history of HFpEF due to mitral regurgitation and complaints of dyspnea on exertion. He had been prescribed multiple medications at an outpatient clinic for CHF management, including azosemide 60 mg/day, bisoprolol 2.5 mg/day, enalapril 2.5 mg/day, spironolactone 50 mg/day, and tolvaptan 15 mg/day. The systolic blood pressure (SBP) of the patient remained at 70–80 mmHg because the use of the diuretic could not be reduced or discontinued owing to edema and weight gain. He was hospitalized for the exacerbation of CHF. Although midodrine 8 mg/day was administered to improve hypotension, the SBP of the patient increased only up to 90 mmHg. On the 35th day after hospitalization, the urine volume decreased significantly (< 100 mL/day) due to hypotension. When droxidopa 200 mg/day replaced intravenous noradrenaline on the 47th day, the SBP remained at 100–120 mmHg and the urine volume increased.

Conclusions

Oral combination treatment with midodrine and droxidopa might contribute to the maintenance of blood pressure and diuretic activity in HFpEF patients with refractory hypotension. However, further long-term studies evaluating the safety and efficacy of this combination therapy for patients with HFpEF are needed.

Potential risks in using midodrine for persistent hypotension after cardiac surgery: a comparative cohort study

Background

Persistent hypotension is a frequent complication after cardiac surgery with cardiopulmonary bypass (CPB). Midodrine, an orally administered alpha agonist, could potentially reduce intravenous vasopressor use and accelerate ICU discharge of otherwise stable patients. The main objective of this study was to explore the clinical impacts of administering midodrine in patients with persistent hypotension after CPB. Our hypothesis was that midodrine would safely accelerate ICU discharge and be associated with more days free from ICU at 30 days.

Results

We performed a retrospective cohort study that included all consecutive patients having received midodrine while being on vasopressor support in the ICU within the first week after cardiac surgery with CPB, between January 2014 and January 2018 at the Montreal Heart Institute. A contemporary propensity score matched control group that included patients who presented similarly prolonged hypotension after cardiac surgery was formed.

After matching, 74 pairs of patients (1:1) fulfilled inclusion criteria for the study and control groups. Midodrine use was associated with fewer days free from ICU (25.8 [23.7–27.1] vs 27.2 [25.9–28] days, p = 0.002), higher mortality (10 (13.5%) vs 1 (1.4%), p = 0.036) and longer ICU length of stay (99 [68–146] vs 68 [48–99] hours, p = 0.001). There was no difference in length of intravenous vasopressors (63 [40–87] vs 44 [26–66] hours, p = 0.052), rate of ICU readmission (6 (8.1%) vs 2 (2.7%), p = 0.092) and occurrence of severe kidney injury (11 (14.9%) vs 10 (13.5%) patients, p = 0.462) between groups.

Conclusion

The administration of midodrine for sustained hypotension after cardiac surgery with CPB was associated with fewer days free from ICU and higher mortality. Routine prescription of midodrine to hasten ICU discharge after cardiac surgery should be used with caution until further prospective studies are conducted.

Effect of midodrine versus placebo on time to vasopressor discontinuation in patients with persistent hypotension in the intensive care unit (MIDAS): an international randomised clinical trial

PURPOSE

ICU discharge is often delayed by a requirement for intravenous vasopressor medications to maintain normotension. We hypothesised that the administration of midodrine, an oral α₁-adrenergic agonist, as adjunct to standard treatment shortens the duration of intravenous vasopressor requirement.

METHODS

In this multicentre, randomised, controlled trial including three tertiary referral hospitals in the US and Australia, we enrolled adult patients with hypotension requiring a single-agent intravenous vasopressor for ≥ 24 h. Subjects received oral midodrine (20 mg) or placebo every 8 h in addition to standard care until cessation of intravenous vasopressors, ICU discharge, or occurrence of adverse events. The primary outcome was time to vasopressor discontinuation. Secondary outcomes included time to ICU discharge readiness, ICU and hospital lengths of stay, and ICU readmission rates.

RESULTS

Between October 2012 and June 2019, 136 participants were randomised, of whom 132 received the allocated intervention and were included in the analysis (modified intention-to-treat approach). Time to vasopressor discontinuation was not different between midodrine and placebo groups (median [IQR], 23.5 [10-54] vs 22.5 [10.4-40] h; difference, 1 h; 95% CI - 10.4 to 12.3 h; p = 0.62). No differences in secondary endpoints were observed. Bradycardia occurred more often after midodrine administration (5 [7.6%] vs 0 [0%], p = 0.02).

CONCLUSION

Midodrine did not accelerate liberation from intravenous vasopressors and was not effective for the treatment of hypotension in critically ill patients.

Real-world droxidopa or midodrine treatment persistence in patients with neurogenic orthostatic hypotension or orthostatic hypotension

BACKGROUND

Neurogenic orthostatic hypotension (nOH) is a subtype of orthostatic hypotension (OH) observed in the presence of neuropathy and is associated with increased risk of falling, impaired function, and poor quality of life. Droxidopa and midodrine are approved in the United States to treat symptomatic nOH and OH in adults, respectively. In this study, we compared the treatment persistence of droxidopa and midodrine.

METHODS

A retrospective analysis of patients prescribed either droxidopa or midodrine was conducted using the Symphony Health Solutions database (Symphony Health Solutions, Phoenix, AZ, USA). Inclusion criteria were (1) a pharmacy insurance claim in at least 16 consecutive quarters from mid-2014 to 2018 and (2) an active prescription for droxidopa or midodrine of ≥30 days' duration during that period. Treatment persistence was defined as the time to the first break in drug coverage of ≥45 days and was capped at 365 days.

RESULTS

Data from 2305 patients who received droxidopa and 117,243 patients who received midodrine were included in this analysis. Median (95% CI) treatment persistence was significantly longer in the droxidopa cohort versus the midodrine cohort (303 [274-325] vs 172 [169-176] days; P < 0.001). After adjustment for confounding factors, patients using droxidopa monotherapy (i.e., without any concomitant midodrine and/or fludrocortisone use) were 16% more likely to be persistent at any time point than patients using midodrine (P < 0.001).

CONCLUSIONS

In this real-world data analysis, patients using droxidopa without concomitant medications for OH were more likely to remain on treatment than patients on midodrine.

Vasoconstrictors in hepatorenal syndrome - A critical review

Hepatorenal syndrome has the worst prognosis among causes of acute kidney injury in cirrhotic patients. Its definitive treatment is liver transplantation. Nevertheless, considering its high short-term mortality rate and the shortage of liver grafts, a pharmacological treatment is of utmost importance, serving as a bridge to liver transplant. The clinical management of hepatorenal syndrome is currently based on the use of a vasoconstrictor in association with albumin. Terlipressin, noradrenaline and the combination of midodrine and octreotide could be used to treat hepatorenal syndrome. Among these options, terlipressin seems to gather the strongest body of evidence regarding efficacy and should be considered the first line of treatment whenever available and in the absence of contraindications. Treatment with a vasoconstrictor and albumin should be promptly initiated after the diagnosis of hepatorenal syndrome in order for patients to have higher chances of recovery.

Clinical utility of midodrine and methylene blue as catecholamine-sparing agents in intensive care unit patients with shock

Shock is common in the intensive care unit, affecting up to one third of patients. Treatment of shock is centered upon managing hypotension and ensuring adequate perfusion via administration of fluids and catecholamine vasopressors. Due to the risks associated with catecholamine vasopressors, interest has grown in using catecholamine-sparing agents such as midodrine and methylene blue. Midodrine is an orally administered alpha-1 adrenergic agonist while methylene blue is an intravenously administered blue dye used to restore vascular tone and increase blood pressure. Separate MEDLINE, Scopus, and Embase database searches were conducted to assess literature revolving around these agents. Examples of search terms included "midodrine", "methylene blue", "critically ill", "shock", and "catecholamine-sparing." Several studies have evaluated their use in patients with shock and found potential benefits in terms of causing significant elevations in blood pressure and hastening catecholamine vasopressor discontinuation with few adverse effects; however, robust evidence is lacking for these off-label indications. Because of the variety of dosing strategies used and the incongruences between patient populations, it is also challenging to define finite recommendations. This review aims to summarize current evidence for the use of midodrine and methylene blue as catecholamine-sparing agents in critically ill patients with resolving or refractory shock.

News in pathophysiology, definition and classification of hepatorenal syndrome: A step beyond the International Club of Ascites (ICA) consensus document

Renal dysfunction is a common, life-threatening complication occurring in patients with liver disease. Hepatorenal syndrome (HRS) has been defined as a purely "functional" type of renal failure that often occurs in patients with cirrhosis in the setting of marked abnormalities in arterial circulation, as well as overactivity of the endogenous vasoactive systems.^4,5 In 2007, the International Club of Ascites (ICA) classified HRS into types 1 and 2 (HRS-1 and HRS-2).⁵ HRS-1 is characterised by a rapid deterioration of renal function that often occurs because of a precipitating event, while HRS-2 is a moderate and stable or slowly progressive renal dysfunction that often occurs without an obvious precipitant. Clinically, HRS-1 is characterised by acute renal failure while HRS-2 is mainly characterised by refractory ascites. Nevertheless, after these two entities were first described, new concepts, definitions, and diagnostic criteria have been developed by nephrologists for renal dysfunction in the general population and hospitalised patients. In particular, the definitions and characterisation of acute kidney injury (AKI), acute kidney disease and chronic kidney disease have been introduced/refined.⁶ Accordingly, a debate among hepatologists of the ICA led to a complete revision of the nomenclature and diagnosistic criteria for HRS-1, which was renamed HRS-AKI.⁷ Additionally, over recent years, greater granularity has been gained regarding the pathogenesis of HRS; it is now increasingly recognised that it is not a purely "functional" entity with haemodynamic derangements, but that systemic inflammation, oxidative stress and bile salt-related tubular damage may contribute significantly to its development. That is, HRS has an additional structural component that would not only make traditional diagnostic criteria less reliable, but would explain the lack of response to pharmacological treatment with vasoconstrictors plus albumin that correlates with a progressive increase in inflammation. Because classification, nomenclature, diagnostic criteria and pathogenic theories have evolved over the years since the traditional classification of HRS-1 and HRS-2 was first described, it was considered that all these novel aspects be reviewed and summarised in a position paper. The aim of this position paper authored by two hepatologists (members of ICA) and two nephrologists involved in the study of renal dysfunction in cirrhosis, is to complete the re-classification of HRS initiated by the ICA in 2012 and to provide an update on the definition, classification, diagnosis, pathophysiology and treatment of HRS.

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.

Pediatric intradialytic hypotension: recommendations from the Pediatric Continuous Renal Replacement Therapy (PCRRT) Workgroup

Intradialytic hypotension (IDH) is a common adverse event resulting in premature interruption of hemodialysis, and consequently, inadequate fluid and solute removal. IDH occurs in response to the reduction in blood volume during ultrafiltration and subsequent poor compensatory mechanisms due to abnormal cardiac function or autonomic or baroreceptor failure. Pediatric patients are inherently at risk for IDH due to the added difficulty of determining and attaining an accurate dry weight. While frequent blood pressure monitoring, dialysate sodium profiling, ultrafiltration-guided blood volume monitoring, dialysate cooling, hemodiafiltration, and intradialytic mannitol and midodrine have been used to prevent IDH, they have not been extensively studied in pediatric population. Lack of large-scale studies on IDH in children makes it difficult to develop evidence-based management guidelines. Here, we aim to review IDH preventative strategies in the pediatric population and outlay recommendations from the Pediatric Continuous Renal Replacement Therapy (PCRRT) Workgroup. Without strong evidence in the literature, our recommendations from the expert panel reflect expert opinion and serve as a valuable guide.

A randomized placebo-controlled trial

BACKGROUND & AIMS

Patients with decompensated cirrhosis on the waiting list for liver transplantation (LT) commonly develop complications that may preclude them from reaching LT. Circulatory dysfunction leading to effective arterial hypovolemia and activation of vasoconstrictor systems is a key factor in the pathophysiology of complications of cirrhosis. The aim of this study was to investigate whether treatment with midodrine, an alpha-adrenergic vasoconstrictor, together with intravenous albumin improves circulatory dysfunction and prevents complications of cirrhosis in patients awaiting LT.

METHODS

A multicenter, randomized, double-blind, placebo-controlled trial (NCT00839358) was conducted, including 196 consecutive patients with cirrhosis and ascites awaiting LT. Patients were randomly assigned to receive midodrine (15-30 mg/day) and albumin (40 g/15 days) or matching placebos for one year, until LT or drop-off from inclusion on the waiting list. The primary endpoint was incidence of any complication (renal failure, hyponatremia, infections, hepatic encephalopathy or gastrointestinal bleeding). Secondary endpoints were mortality, activity of endogenous vasoconstrictor systems and plasma cytokine levels.

RESULTS

There were no significant differences between both groups in the probability of developing complications of cirrhosis during follow-up (p = 0.402) or one-year mortality (p = 0.527). Treatment with midodrine and albumin was associated with a slight but significant decrease in plasma renin activity and aldosterone compared to placebo (renin -4.3 vs. 0.1 ng/ml.h, p < 0.001; aldosterone -38 vs. 6 ng/dl, p = 0.02, at week 48 vs. baseline). Plasma norepinephrine only decreased slightly at week 4. Neither arterial pressure nor plasma cytokine levels changed significantly.

CONCLUSIONS

In patients with cirrhosis awaiting LT, treatment with midodrine and albumin, at the doses used in this study, slightly suppressed the activity of vasoconstrictor systems, but did not prevent complications of cirrhosis or improve survival.

LAY SUMMARY

Patients with cirrhosis who are on the liver transplant waiting list often develop complications which prevent them from receiving a transplant. Circulatory dysfunction is a key factor behind a number of complications. This study was aimed at investigating whether treating patients with midodrine (a vasoconstrictor) and albumin would improve circulatory dysfunction and prevent complications. This combined treatment, at least at the doses administered in this study, did not prevent the complications of cirrhosis or improve the survival of these patients.

Delayed orthostatic hypotension: Severity of clinical symptoms and response to medical treatment

INTRODUCTION

Severity of orthostatic intolerance and the benefit of medical treatment in patients with delayed OH have not been elucidated. This study aimed to compare the symptom severity between classic and delayed OH and evaluate the efficacy of midodrine or pyridostigmine in patients with delayed OH.

METHODS

This was an adjunctive study of previously reported randomized, open-label clinical trials evaluating the efficacy and safety of midodrine or pyridostigmine for classic OH. Seventeen patients with delayed OH were enrolled and also received midodrine (2.5 mg twice a day) or pyridostigmine (30 mg twice a day) alone or combined. Result of initial orthostatic vital sign and questionnaires were compared between the patients with delayed OH and previously reported 87 patients with classic OH. Delayed OH patients were followed up at 1 and 3 months post-treatment and the vital sign measurements and questionnaires were repeated during the follow-up period.

RESULTS

Questionnaire scores regarding OH-related symptoms, depression and health-related quality of life (HRQOL) were comparable between the classic and delayed OH patients at baseline. OH-related symptoms and depression were significantly improved after 3 months of medical treatment.

CONCLUSION

Patients with delayed OH exhibited orthostatic intolerance similar to that of classic OH. This study shows that these patients may benefit from medical treatment with either midodrine or pyridostigmine.

[Syncope in children and adolescents]

Syncope is common in children and adolescents. Neurally mediated syncope including pallid and cyanotic breath holding spells, vagovasal syncope and neurocardiogenic syncope is based on a common pathomechanism and accounts for approximately 75% of cases. A potentially life-threatening cardiac cause of syncope may be present in up to 6%. Detailed history, physical examination and 12-lead electrocardiogram (ECG) allow discrimination between benign and serious syncope in the majority of pediatric patients. Tilt-testing can be useful when diagnosis is unclear. In neurally mediated syncope, education on awareness of prodromes, modification of life-style and reassurance of the family on benign character of the disease is sufficient for preventing further syncopal episodes in the majority of cases. In pediatric patients unresponsive to these measures midodrine is often effective. Fludrocortisone and cardiac pacing may be considered in selected patients. β‑Blockers are not beneficial in pediatric neurally mediated syncope. Cardiac causes need specific disease-targeted therapy.

Use of fludrocortisone for intradialytic hypotension

Intradialytic hypotension during dialysis adversely affects a patient’s prognosis and increases mortality. We report a case in which intradialytic hypotension that persisted after the administration of midodrine was relieved after the use of fludrocortisone. Administration of 0.2 mg of fludrocortisone occurred 30 minutes before dialysis. We compared 45 sessions of dialysis without fludrocortisone administration and 45 sessions of dialysis with fludrocortisone administration in one patient. The number of times in which systolic blood pressure became lower than 80 mmHg and the number of early terminations of dialysis due to a decrease in systolic blood pressure were higher in the sessions without fludrocortisone administration than in the sessions with fludrocortisone administration (P < 0.05). Fludrocortisone may be helpful for the treatment of intradialytic hypotension that does not respond to midodrine administration.

Midodrine as adjunctive support for treatment of refractory hypotension in the intensive care unit: a multicenter, randomized, placebo controlled trial (the MIDAS trial)

BACKGROUND

Patients admitted to intensive care units (ICU) are often treated with intravenous (IV) vasopressors. Persistent hypotension and dependence on IV vasopressors in otherwise resuscitated patients lead to delay in discharge from ICU. Midodrine is an oral alpha-1 adrenergic agonist approved for treatment of symptomatic orthostatic hypotension. This trial aims to evaluate whether oral administration of midodrine is an effective adjunct to standard therapy to reduce the duration of IV vasopressor treatment, and allow earlier discharge from ICU and hospital.

METHODS

The MIDAS trial is an international, multicenter, randomized, double-blind, placebo-controlled clinical trial being conducted in the USA and Australia. We are targeting 120 patients. Adult patients admitted to the ICU who are resuscitated and otherwise stable on low dose IV vasopressors for at least 24 h will be considered for recruitment. Participants will be randomized to receive midodrine (20 mg) or placebo three times a day, in addition to standard care. The primary outcome is time (hours) from initiation of midodrine or placebo to discontinuation of IV vasopressors. Secondary outcomes include time (hours) from ICU admission to discharge readiness, ICU length of stay (LOS) (days), hospital LOS (days), rates of ICU readmission, and rates of adverse events related to midodrine administration.

DISCUSSION

Midodrine is approved by the Food and Drug Administration (FDA) for the treatment of symptomatic orthostatic hypotension. In August 2010, FDA proposed to withdraw approval of midodrine because of lack of studies that verify the clinical benefit of the drug. We obtained Investigational New Drug (IND 113,330) approval to study its effects in critically ill patients who require IV vasopressors but are otherwise ready for discharge from the ICU. A pilot observational study in a cohort of surgical ICU patients showed that the rate of decline in vasopressor requirements increased after initiation of midodrine treatment. We hypothesize that midodrine administration is effective to wean IV vasopressors and shorten ICU and hospital LOS. This trial may have significant implications on lowering costs of hospital care and obtaining FDA approval for new indications for midodrine.

TRIAL REGISTRATION

This study has been registered at clinicaltrials.gov on 02/09/2012 (NCT01531959).

The recommendations of a consensus panel for the screening, diagnosis, and treatment of neurogenic orthostatic hypotension and associated supine hypertension

Neurogenic orthostatic hypotension (nOH) is common in patients with neurodegenerative disorders such as Parkinson’s disease, multiple system atrophy, pure autonomic failure, dementia with Lewy bodies, and peripheral neuropathies including amyloid or diabetic neuropathy. Due to the frequency of nOH in the aging population, clinicians need to be well informed about its diagnosis and management. To date, studies of nOH have used different outcome measures and various methods of diagnosis, thereby preventing the generation of evidence-based guidelines to direct clinicians towards ‘best practices’ when treating patients with nOH and associated supine hypertension. To address these issues, the American Autonomic Society and the National Parkinson Foundation initiated a project to develop a statement of recommendations beginning with a consensus panel meeting in Boston on November 7, 2015, with continued communications and contributions to the recommendations through October of 2016. This paper summarizes the panel members’ discussions held during the initial meeting along with continued deliberations among the panel members and provides essential recommendations based upon best available evidence as well as expert opinion for the (1) screening, (2) diagnosis, (3) treatment of nOH, and (4) diagnosis and treatment of associated supine hypertension.

A novel, sensitive and selective method of UPLC/MS-MS for rapid simultaneous determination of midodrine and its active metabolite desglymidodrine in human plasma: Application to support bioequivalence study in healthy human volunteers

A specific, rapid, sensitive and selective ultra-performance liquid chromatography - tandem mass spectrometry has been developed for the simultaneous determination of midodrine and desglymidodrine in human plasma. The analytes and its deuterated analogs were quantitatively extracted from 100μL of human plasma by solid phase extraction technique. Separation of analytes was achieved on the Waters Acquity UPLC BEH C18 (50×2.1mm, 1.7μm) column using acetonitrile-4.0mM ammonium formate, pH 2.5(90:10, v/v) as mobile phase. The protonated analytes were quantified by selected reaction monitoring in the positive ionization mode by triple quadrupole mass spectrometer. The calibration plots were linear over the concentration range of 0.050-50.0ng/mL. The intra-batch and inter-batch precision (%CV) across quality control levels was <4.0 and the% mean relative recovery was ≥96%. Various other parameters like stability in different conditions; matrix effect and reproducibility of the method were performed in accordance with the guidelines specified by the USFDA for bioanalytical method development and validation. The developed method was successfully administered to the pharmacokinetics study of 5 mg midodrine tablet in 12 healthy subjects. Reproducibility of assay was proved by reanalysis of 48 incurred samples.

Effects of midodrine and L-NAME on systemic and cerebral hemodynamics during cognitive activation in spinal cord injury and intact controls

We previously showed that increases in mean arterial pressure (MAP) following administration of midodrine hydrochloride (MH) and nitro‐L‐arginine methyl ester (L‐NAME) resulted in increased mean cerebral blood flow velocity (MFV) during head‐up tilt in hypotensive individuals with spinal cord injury (SCI) and question if this same association was evident during cognitive activation. Herein, we report MAP and MFV during two serial subtraction tasks (SSt) given before (predrug) and after (postdrug) administration of MH; (10 mg), L‐NAME (1 mg/kg) or no drug (ND) in 15 subjects with SCI compared to nine able‐bodied (AB) controls. Three‐way factorial analysis of variance (ANOVA) models were used to determine significant main and interaction effects for group (SCI, AB), visit (MH, L‐NAME, ND), and time (predrug, postdrug) for MAP and MFV during the two SSt. The three‐way interaction was significant for MAP (F = 4.262; P = 0.020); both MH (30 ± 26 mmHg; P < 0.05) and L‐NAME (27 ± 22 mmHg; P < 0.01) significantly increased MAP in the SCI group, but not in the AB group. There was a significant visit by time interaction for MFV suggesting an increase from predrug to postdrug following L‐NAME (6 ± 8 cm/sec; P < 0.05) and MH (4 ± 7 cm/sec; P < 0.05), regardless of study group, with little change following ND (3 ± 3 cm/sec). The relationship between change in MAP and MFV was significant in the SCI group following administration of MH (r² = 0.38; P < 0.05) and L‐NAME (r² = 0.32; P < 0.05). These antihypotensive agents, at the doses tested, raised MAP, which was associated with an increase MFV during cognitive activation in hypotensive subjects with SCI.

Clinical benefit of midodrine hydrochloride in symptomatic orthostatic hypotension: a phase 4, double-blind, placebo-controlled, randomized, tilt-table study

Objective

Midodrine hydrochloride is a short-acting pressor agent that raises blood pressure in the upright position in patients with orthostatic hypotension. The US Food and Drug Administration’s Subpart H approval, under which midodrine was initially approved, requires post-marketing studies to confirm midodrine’s clinical benefit in this indication. The purpose of this study was to evaluate the clinical benefit of midodrine with regard to symptom response.

Methods

This was a double-blind, placebo-controlled, randomized, crossover, multicenter study (NCT01518946). Following screening, patients aged ≥18 years with severe symptomatic orthostatic hypotension and on a stable dose of midodrine for at least 3 months were randomized to treatment with either their previous midodrine dose or placebo on day 1 and the respective alternate treatment on day 2. The primary endpoint measured time to syncopal symptoms or near-syncope using a 45-min tilt-table test at 1 h post-dose.

Results

Thirty-three patients were screened for inclusion: 19 received at least one dose of midodrine and had at least one post-dose measurement of the primary endpoint. The least-squares mean time to syncopal symptoms or near-syncope after tilt-table initiation (mean ± standard error) was 1626.6 ± 186.8 s for midodrine and 1105.6 ± 186.8 s for placebo (difference, 521.0 s; 95 % confidence interval 124.2–971.7 s; p = 0.0131). There were 15 adverse events in 10 patients; all of these were mild or moderate in severity, with none considered by the investigators to be related to midodrine.

Interpretation

Midodrine is a well-tolerated and clinically effective treatment for symptomatic orthostatic hypotension.

Neurogenic orthostatic hypotension: roles of norepinephrine deficiency in its causes, its treatment, and future research directions

BACKGROUND

Although a diversity of neurotransmitters and hormones participate in controlling blood pressure, norepinephrine released from postganglionic sympathetic nerve terminals is an important mediator of the rapid regulation of cardiovascular function required for homeostasis of cerebral perfusion. Hence, neurogenic orthostatic hypotension (NOH) often represents a deficiency of noradrenergic responsiveness to postural change.

RESEARCH DESIGN AND METHODS

PubMed searches with 'orthostatic hypotension' and 'norepinephrine' as conjoint search terms and no restriction on language or date, so as to survey the pathophysiologic and clinical relevance of norepinephrine deficiency for current NOH interventions and for future directions in treatment and research.

RESULTS

Norepinephrine deficiency in NOH can arise peripherally, due to cardiovascular sympathetic denervation (as in pure autonomic failure, Parkinson's disease, and a variety of neuropathies), or centrally, due to a failure of viscerosensory signals to generate adequate sympathetic traffic to intact sympathetic nerve endings (as in multiple system atrophy). Nonpharmacologic countermeasures such as pre-emptive water intake may yield blood-pressure increases exceeding those achieved pharmacologically. For patients with symptomatic NOH unresponsive to such strategies, a variety of pharmacologic interventions have been administered off-label on the basis of drug mechanisms expected to increase blood pressure via blood-volume expansion or vasoconstriction. Two pressor agents have received FDA approval: the sympathomimetic midodrine and more recently the norepinephrine prodrug droxidopa.

CONCLUSIONS

Pressor agents are important for treating symptomatic NOH in patients unresponsive to lifestyle changes alone. However, the dysautonomia underlying NOH often permits blood-pressure excursions toward both hypotension and hypertension. Future research should aim to shed light on the resulting management issues, and should also explore the possibility of pharmacotherapy selectively targeting orthostatic blood-pressure decreases.

Effect of Alpha-1-Adrenergic Agonist, Midodrine for the Management of Long-Standing Neurogenic Shock in Patient with Cervical Spinal Cord Injury: A Case Report

We report a rare case of a 71-year-old male patient who had suffered from long-lasting neurogenic shock for 13 weeks after cervical spinal cord injury (SCI) caused by a bicycle accident. The neurogenic shock was resolved dramatically 2 weeks after the administration of alpha-1-adrenergic agonist, midodrine hydrochloride. In usual cases, neurogenic shock tends to improve between 2 and 6 weeks after SCI; however, in a few cases, the shock lasts for several months. In our case, spinal shock lasted for 13 weeks and exhibited very sensitive decline of blood pressure for even a slight decrease of dopamine despite recovered bulbospongiosus reflex. Three days after midodrine hydrochloride was added, hypotension improved dramatically. We discuss our rare case with pertinent literatures.

Midodrine in patients with spinal cord injury and anejaculation: A double-blind randomized placebo-controlled pilot study

OBJECTIVE

The objective of this study is to evaluate the efficacy of midodrine in the treatment of anejaculation in men with spinal cord injury (SCI).

STUDY DESIGN

Prospective, double-blind, randomized, placebo-controlled pilot study.

METHOD

Men with anejaculation associated with SCI (level of injury above T10) of more than 1 year in duration were approached. Those with no ejaculatory response to one penile vibratory stimulation (PVS) trial were assigned in a double-blind manner to one of the two following interventions once a week for a maximum of 3 weeks or until ejaculation occurred: oral administration of flexible midodrine (7.5-22.5 mg max) followed by PVS (group M), or oral administration of flexible sham-midodrine (placebo) followed by PVS (group P). Sociodemographic data, medical characteristics, and plasma desglymidodrine concentration were collected for all participants.

OUTCOME MEASURE

Ejaculation success rate in each group.

RESULTS

Among the 78 men approached, 23 participants (level of SCI: C4-T9) were randomized. Three participants abandoned the study and 20 completed the study; 10 were assigned to group M, 10 to group P. Ejaculation was reached for one participant of group M and for two participants of group P. Autonomic dysreflexia associated to PVS occurred in three patients.

CONCLUSION

In this small sample study, treatment of anejaculation after SCI with midodrine and PVS did not result in a better rate of antegrade ejaculation in 10 men than in 10 men treated with a placebo and PVS.

Early discontinuation of treatment in patients with orthostatic hypotension

BACKGROUND

Midodrine and fludrocortisone are considered the first-line pharmacologic treatments for orthostatic hypotension (OH). Although OH is thought to require long-term therapy, it is unknown how long patients remain on treatment ("persistence").

METHODS

We assembled a retrospective cohort of patients with OH aged ≥ 50 years enrolled in Tennessee Medicaid (1996-2008), and identified new episodes of midodrine and fludrocortisone use. Follow-up continued from the first medication fill through treatment discontinuation (90 days without medication), change in treatment, death, hospitalization, and loss of enrollment or study end. We compared persistence on treatment using Cox regression models and fludrocortisone as reference. Covariates included demographics, healthcare utilization measurements and co-morbidities.

RESULTS

We identified 1704 OH patients, who initiated 1767 episodes of fludrocortisone (1103) or midodrine (664) use. The median age was 69 years, 53% were female and 80% were white. During 738 person years of follow-up, episodes of use ended because of treatment discontinuation in 467 (27% fludrocortisone, 25% midodrine); treatment change in 72 (3% fludrocortisone, 6% midodrine) and death in 53 (3% fludrocortisone, 2% midodrine). Overall median persistence on fludrocortisone and midodrine was 254 (IQR: 119-783) and 259 (IQR: 119-807) days, respectively. The adjusted hazard ratio (aHR) for overall non-persistence on midodrine compared to fludrocortisone was 1.07 (95% CI: 0.90-1.28).

CONCLUSIONS

Overall duration of OH treatment with first-line medications was short, and similar for fludrocortisone and midodrine. Further research is warranted to determine the causes of this low persistence. (Words#234).

Oral midodrine treatment accelerates the liberation of intensive care unit patients from intravenous vasopressor infusions

PURPOSE

Persistent low-level hypotension represents a barrier to discharging patients from the intensive care unit (ICU). Midodrine may be an effective adjunct to wean intravenous (IV) vasopressors and permit ICU discharge. We tested the hypothesis that midodrine, given to patients on IV vasopressors who otherwise met ICU discharge criteria, increased the magnitude of change in IV vasopressor rate.

MATERIALS AND METHODS

This was a prospective, observational study in 20 adult surgical ICU patients who met ICU discharge criteria except for an IV vasopressor requirement. We compared the change in phenylephrine equivalent rates during the day before midodrine to the change in phenylephrine equivalent rates after midodrine initiation and analyzed changes in total body fluid balance, heart rate, mean arterial pressure, and white blood cell count during this period.

RESULTS

Patients received 41.0±33.4 μg/min of phenylephrine equivalents and the change in IV vasopressor rate (slope) decreased significantly from -0.62 μg/min per hour of phenylephrine equivalents before midodrine to -2.20 μg/min per hour following the initiation of midodrine treatment (P=.012). Change in total body fluid balance, heart rate, mean arterial pressure, and white blood cell count did not correlate with change in IV vasopressor rate.

CONCLUSION

Midodrine treatment was associated with an increase in the magnitude of decline of the IV vasopressor rate. Oral midodrine may facilitate liberation of surgical ICU patients from an IV vasopressor infusion, and this may affect discharge readiness of patients from the ICU.

Comparison of the effect of midodrine versus octreotide on hemodynamic status in cirrhotic patients with ascites

BACKGROUND

In cirrhotic patients peripheral vasodilatation may decrease renal blood flow and subsequently raises plasma renin activity. Octreotide with several mechanisms causes peripheral arterial vasoconstriction. Midodrine is an alpha agonist and acts as a peripheral vasoconstrictor; therefore it may reduce plasma renin activity and improve renal function. In this study the effects of these two agents were compared on cirrhotic patients to determine their ability to reduce plasma renin activity and increase GFR.

METHODS

This study was a randomized clinical trial and was performed in Al-Zahra hospital in 2008-2009; 34 patients with CHILD C cirrhosis enrolled in this study. They were randomly divided into two groups. First group were treated by 3 days of subcutaneous octreotide 50 μg tid (n = 17). For the second group oral midodrine 7.5 mg tid was administrated for 3 days. Plasma renin activity, blood pressure, glomerular filtration rate, and body weight were measured and compared before and after therapy in both groups.

RESULTS

In both groups, plasma rennin activity decreased significantly after treatment. The present study showed that both midodrine and octreotide can reduce plasma renin activity but midodrine can reduce PRA and increase GFR more potently than octreotide.

CONCLUSIONS

Midodrine has a favorable hemodynamic effect in nonazotemic cirrhotic patients by decreasing plasma renin activity and increasing GFR.

Management and therapy of vasovagal syncope: A review

Vasovagal syncope is a common cause of recurrent syncope. Clinically, these episodes may present as an isolated event with an identifiable trigger, or manifest as a cluster of recurrent episodes warranting intensive evaluation. The mechanism of vasovagal syncope is incompletely understood. Diagnostic tools such as implantable loop recorders may facilitate the identification of patients with arrhythmia mimicking benign vasovagal syncope. This review focuses on the management of vasovagal syncope and discusses the non-pharmacological and pharmacological treatment options, especially the use of midodrine and selective serotonin reuptake inhibitors. The role of cardiac pacing may be meaningful for a subgroup of patients who manifest severe bradycardia or asystole but this still remains controversial.