Pharmacokinetic and pharmacodynamic effects of midodrine on blood pressure, the autonomic nervous system, and plasma natriuretic peptides: a prospective, randomized, single-blind, two-period, crossover, placebo-controlled study

Adjunctive Midodrine Therapy for Vasopressor-Dependent Shock in the ICU: A Systematic Review and Meta-Analysis

OBJECTIVES

To summarize the efficacy of midodrine as an adjunctive therapy in critically ill patients. Safety of midodrine was assessed as a secondary outcome.

DATA SOURCES

We performed a systematic review and meta-analysis using a peer-reviewed search strategy combining the themes of vasopressor-dependent shock, critical care, and midodrine and including MEDLINE, Ovid Embase, CINAHL, and Cochrane library databases until September 14, 2023.

STUDY SELECTION

We included studies if they: 1) included patients with vasopressor-dependent shock, 2) were performed in the ICU, 3) evaluated oral midodrine therapy compared with placebo or usual care, and 4) evaluated one of the outcomes of interest.

DATA EXTRACTION

We extracted data independently in duplicate using standardized data abstraction forms, which included the following specific variables: patient characteristics, age, sex, type of ICU, etiology of shock, number of patients, study inclusion and exclusion criteria, and geographical location. We also captured the type, dose, and duration of IV vasopressors, any cointervention used, and outcome data.

DATA SYNTHESIS

We identified seven randomized controlled trials (six included in the pooled analysis) and ten observational studies (four included in the pooled analysis) that met eligibility criteria. Adjunctive midodrine may decrease ICU length of stay (LOS) and there is low certainty of effect on hospital LOS. Midodrine may decrease IV vasopressor support duration, ICU mortality, and hospital mortality. Pooled observational data was based on very low certainty data for all outcomes of interest. The trial sequential analysis-informed required sample size was not met for ICU LOS or IV vasopressor duration and this contributed to Grading of Recommendations, Assessment, Development, and Evaluations assessments of imprecision for both outcomes.

CONCLUSIONS

Adjunctive midodrine may decrease ICU LOS, duration of IV vasopressor therapy, and mortality in critically ill patients. However, required sample sizes was not met to determine our outcomes of interest. Midodrine may increase risk of bradycardia. While midodrine may provide benefit for patient-centered outcomes, due to increased risk of adverse events, further large-scale studies are needed to inform and guide its routine use in the ICU.

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 .

Midodrine use in critically ill patients: a narrative review

Midodrine is a peripherally acting, oral α-agonist that is increasingly used in intensive care units despite conflicting evidence for its effectiveness. It has pharmacological effects on blood vessels as well as pupillary, cardiac, renal, gastrointestinal, genitourinary, lymphatic and skin tissue. It has approval for use as a treatment for orthostatic hypotension, but a surge in interest over the past decade has prompted its use for a growing number of off-label indications. In critically ill patients, midodrine has been used as either an adjunctive oral therapy to wean vasoplegic patients off low dose intravenous vasopressor infusions, or as an oral vasopressor agent to prevent or minimise the need for intravenous infusion. Clinical trials have mostly focused on midodrine as an intravenous vasopressor weaning agent. Early retrospective studies supported its use for this indication, but more recent randomised controlled trials have largely refuted this practice. Key questions remain on its role in managing critically ill patients before intensive care admission, during intensive care stay, and following discharge. This narrative review presents a comprehensive overview of midodrine use for the critical care physician and highlights why lingering questions around ideal patient selection, dosing, timing of initiation, and efficacy of midodrine for critically ill patients remain unanswered.

Midodrine therapy for vasopressor dependent shock in the intensive care unit: a protocol for a systematic review and meta-analysis

INTRODUCTION

Intensive care unit (ICU) lengths of stay are modified by ongoing need for haemodynamic support in critically ill patients. This is most commonly provided by intravenous vasopressor therapy. Midodrine has been used as an oral agent for haemodynamic support in patients with orthostatic hypotension or cirrhosis. However, its efficacy in treating shock in the ICU, particularly for patients weaning from intravenous vasopressors, remains uncertain. The objective of this systematic review is to determine the efficacy of midodrine in vasopressor dependent shock.

METHODS AND ANALYSIS

We will search Ovid MEDLINE, Ovid Embase, CINAHL and Cochrane Library for observational trials and randomised controlled trials evaluating midodrine in critically ill patients from inception to 21 April 2022. We will also review unpublished data and relevant conference abstracts. Outcomes will include ICU length of stay, duration of intravenous vasopressor support, ICU mortality, hospital mortality, hospital length of stay and rates of ICU readmission. Data will be analysed in aggregate, where appropriate. We will evaluate risk of bias using the modified Cochrane tool and certainty of evidence using Grading of Recommendations, Assessment, Development and Evaluations methodology. We will perform trial sequential analysis for the outcome of ICU length of stay.

ETHICS AND DISSEMINATION

Ethics approval is not required as primary data will not be collected. Findings of this review will be disseminated through peer-related publication and will inform future clinical trials.

PROSPERO REGISTRATION NUMBER

CRD42021260375.

Biomarkers and Hemodynamic Parameters in the Diagnosis and Treatment of Children with Postural Tachycardia Syndrome and Vasovagal Syncope

In children, vasovagal syncope and postural tachycardia syndrome constitute the major types of orthostatic intolerance. The clinical characteristics of postural tachycardia syndrome and vasovagal syncope are similar but their treatments differ. Therefore, their differential diagnosis is important to guide the correct treatment. Therapeutic methods vary in patients with the same diagnosis because of different pathomechanisms. Hence, in patients with vasovagal syncope or postural tachycardia syndrome, routine treatments have an unsatisfactory efficacy. However, biomarkers could increase the therapeutic efficacy significantly, allowing for an accurate and detailed assessment of patients and leading to improved therapeutic effects. In the present review, we aimed to summarize the current state of research into biomarkers for distinguishing the diagnosis of pediatric vasovagal syncope from that of postural tachycardia syndrome. We also discuss the biomarkers that predict treatment outcomes during personalized therapy for each subtype.

LIBERATE: a study protocol for midodrine for the early liberation from vasopressor support in the intensive care unit (LIBERATE): protocol for a randomized controlled trial

Background

Intravenous (IV) vasopressors to support hemodynamics are a primary indication for intensive care unit (ICU) admission. Utilization of oral vasopressor therapy may offer an alternative to IV vasopressor therapy in the ICU, thus decreasing the need for ICU admission. Oral vasopressors, such as midodrine, have been used for hemodynamic support in non-critically ill patients, but their evaluation in critically ill patients to potentially spare IV vasopressor therapy has been limited.

Methods

The LIBERATE study will be a multicenter, parallel-group, blinded, randomized placebo-controlled trial. It will recruit adult (i.e., age ≥ 18 years) critically ill patients receiving stable or decreasing doses of IV vasopressors. Eligible patients will be randomized to receive either midodrine 10 mg administered enterally every 8 h or placebo until 24 h post-discontinuation of IV vasopressors. The primary outcome will be ICU length of stay. Secondary outcomes include all-cause mortality at 90 days, hospital length of stay, length of IV vasopressor support, re-initiation of IV vasopressors, rates of ICU readmission, and occurrence of AEs. Health economic outcomes including ICU, hospital and healthcare costs, and cost-effectiveness will be evaluated. Pre-planned subgroup analyses include age, sex, frailty, severity of illness, etiology of shock, and comorbid conditions.

Discussion

LIBERATE will rigorously evaluate the effect of oral midodrine on duration of ICU stay and IV vasopressor support in critically ill patients.

Trial registration

ClinicalTrials.gov NCT05058612. Registered on September 28, 2021

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06115-0.

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.

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.

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.

Oral Midodrine Hydrochloride for Prevention of Orthostatic Hypotension during Early Mobilization after Hip Arthroplasty

Background

Early postoperative mobilization is essential for rapid recovery but may be impaired by orthostatic intolerance (OI) and orthostatic hypotension (OH), which are highly prevalent after major surgery. Pathogenic mechanisms include an insufficient postoperative vasopressor response. The oral α-1 agonist midodrine hydrochloride increases vascular resistance, and the authors hypothesized that midodrine would reduce the prevalence of OH during mobilization 6 h after total hip arthroplasty relative to placebo.

Methods

This double-blind, randomized trial allocated 120 patients 18 yr or older and scheduled for total hip arthroplasty under spinal anesthesia to either 5 mg midodrine hydrochloride or placebo orally 1 h before mobilization at 6 and 24 h postoperatively. The primary outcome was the prevalence of OH (decrease in systolic or diastolic arterial pressures of &gt; 20 or 10 mmHg, respectively) during mobilization 6 h after surgery. Secondary outcomes were OI and hemodynamic responses to mobilization at 6 and 24 h.

Results

At 6 h, 14 (25%; 95% CI, 14 to 38%) versus 23 (39.7%; 95% CI, 27 to 53%) patients had OH in the midodrine and placebo group, respectively, relative risk 0.63 (0.36 to 1.10; P = 0.095), whereas OI was present in 15 (25.0%; 15 to 38%) versus 22 (37.3%; 25 to 51%) patients, relative risk 0.68 (0.39 to 1.18; P = 0.165). At 24 h, OI and OH prevalence did not differ between groups.

Conclusions

Preemptive use of oral 5 mg midodrine did not significantly reduce the prevalence of OH during early postoperative mobilization compared with placebo. However, further studies on dose and timing are warranted since midodrine is effective in chronic OH conditions.

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.

Plasma copeptin and therapeutic effectiveness of midodrine hydrochloride on postural tachycardia syndrome in children

OBJECTIVES

Midodrine hydrochloride is used clinically to treat children with postural tachycardia syndrome (POTS), but it is not effective in all patients. This study was designed to explore the changes in plasma copeptin and its predictive value in assessing the therapeutic efficacy of midodrine hydrochloride in children with POTS.

STUDY DESIGN

The study included 33 children with POTS and 26 healthy children. The group with POTS received midodrine hydrochloride treatment for 1.5-3 months. The plasma copeptin was measured using a sandwich immunoluminometric assay. A receiver operating characteristic curve was used to explore the predictive value of plasma copeptin.

RESULTS

The plasma copeptin in the group with POTS was significantly higher than that of the control group (10.827±2.459 pmol/L vs 8.845±1.471 pmol/L, P<.001). The plasma copeptin in responders to midodrine hydrochloride was significantly higher than that of nonresponders (12.082±1.998 pmol/L vs 9.646±2.301 pmol/L, P=.003). Receiver operating characteristic analysis on the predictive value of plasma copeptin showed that the area under the curve was 0.800 with a 95% CI of 0.640-0.959. Using a plasma copeptin level of 10.482 pmol/L as the cutoff point produced both favorite sensitivity (81.3%) and specificity (76.5%) in predicting the efficacy of midodrine hydrochloride therapy in children with POTS.

CONCLUSIONS

Plasma copeptin may be considered as a predictive biomarker for the likelihood of successful treatment of children with POTS with midodrine hydrochloride.

Therapy for diabetic neuropathy: an overview

Neuropathy is a highly prevalent complication of diabetes that is only likely to increase as the diabetic epidemic continues. Unfortunately, the only disease-modifying treatment is to address the underlying diabetes with enhanced glucose control. In patients with type 1 diabetes, improved glycemic control dramatically reduces the incidence of neuropathy. In contrast, in patients with type 2 diabetes, better glucose control has only a marginal effect on the prevention of neuropathy. However, recognition and treatment of neuropathic pain is also important. An ever expanding number of randomized, controlled clinical trials support multiple medications for the reduction of pain. This includes medications such as calcium channel agonists, tricyclic antidepressants, and selective serotonin/norepinephrine reuptake inhibitors. However, the precise order and combination of these medications remains unclear. Furthermore, several new promising medications are being developed. Overall, the cornerstones of the treatment of diabetic neuropathy are improved glycemic control and initiation of a neuropathic pain medication with high levels of evidence to support its use when pain is present.

Flow-mediated vasodilation as a predictor of therapeutic response to midodrine hydrochloride in children with postural orthostatic tachycardia syndrome

This study was designed to explore the value of flow-mediated vasodilation (FMD) as a predictor of therapeutic response to midodrine hydrochloride (MD) in children with postural orthostatic tachycardia syndrome (POTS). One hundred and eight children diagnosed with POTS and 20 healthy control children were enrolled. All children with POTS received MD and were followed up for 3 months. FMD of brachial artery for each participant was measured by vascular ultrasound. Symptom scores, FMD values, and head-up test (HUT)/head-up tilt test (HUTT) outcomes were investigated before and after treatment. A receiver operating characteristic curve was used to explore the value of FMD as a predictor. Baseline FMD (%) and increased heart rate (beats per minute) during HUT/HUTT were significantly greater in children with POTS compared with control children (FMD: 11 ± 3% vs 6 ± 2%, p <0.001; increased heart rate: 38 ± 9 vs 7 ± 7 beats/min, p <0.001, respectively). Before treatment, MD responders had greater FMD values than MD nonresponders (p <0.05). Symptom scores, excessive increases in heart rate during HUT, and increased FMD values were all reduced significantly after treatment (all p <0.05). The receiver operating characteristic curve for the predictive value of FMD showed the area under the curve to be 0.790 (95% confidence interval: 0.679 to 0.902; p <0.001) at 1-month and 0.803 (95% confidence interval: 0.669 to 0.936; p <0.01) at 3-month therapy. FMD of 9.85% had a high sensitivity (1-month therapy: 71.6%; 3-month therapy: 74.4%) and specificity (1-month therapy 77.8%; 3-month therapy: 80%). In conclusion, FMD is a predictor of the efficacy of MD for treating children with POTS.

Rationale for the prevention of syncope trial IV: assessment of midodrine

BACKGROUND

Vasovagal syncope is a common problem associated with a poor quality of life, which improves when the frequency of syncope is reduced. Effective pharmacological therapies for vasovagal syncope have been elusive. Midodrine is a pro-drug whose primary metabolite is an alpha-1 adrenoreceptor agonist. A few studies have suggested that it may be beneficial in syncope, but all have had significant methodological limitations. A placebo-controlled clinical trial of midodrine for the prevention of vasovagal syncope is needed.

STRUCTURE OF STUDY

The prevention of syncope trial IV (POST 4) is a multicenter, international, randomized, placebo-controlled study of midodrine in the prevention of vasovagal syncope. The primary end point is the time to first recurrence of syncope. Patients will be randomized 1:1 to receive midodrine 10-30 mg/day or matching placebo, and followed for 1 year. Secondary end points include syncope frequency, presyncope, and quality of life. Primary analysis will be performed with an intention-to-treat approach, with a secondary on-treatment analysis.

POWER CALCULATIONS

A total sample size of 112, split equally between the two groups, achieves 85 % power to detect a 50 % relative risk reduction when the event rates are 55 and 27.5 % in the placebo and midodrine arms. Allowing for 20 % dropout, we propose to enroll 140 patients.

REGISTRATION

POST 4 is registered with http://www.clinicaltrials.gov (NCT01456481).

IMPLICATIONS

This study will be the first adequately powered trial to determine whether midodrine is effective in preventing vasovagal syncope. If it is effective, then midodrine may become the first-line pharmacological therapy for this condition.

Treatment of dysautonomia in extrapyramidal disorders

Although extrapyramidal diseases are commonly thought to solely affect the extrapyramidal motor system, nonmotor symptoms such as behavioural abnormalities, dysautonomia, sleep disturbances and sensory dysfunctions are also frequently observed. Autonomic dysfunction as an important clinical component of extrapyramidal disease (idiopathic Parkinson's disease, multiple system atrophy, progressive supranuclear palsy, dementia with Lewy bodies) is often not formally assessed and thus frequently misdiagnosed. Symptoms of autonomic dysfunction in general impact more on quality of life than motor symptoms. Appropriate symptom-oriented diagnosis and symptomatic treatment as part of an interdisciplinary approach can greatly benefit the patient. Unfortunately, double-blind, randomized, controlled studies are scarce with the consequence that most recommendations are not based on the highest level of evidence. This review elaborates a limited overview on the treatment of cardiovascular, gastrointestinal, urogenital and sudomotor autonomic dysfunction in various extrapyramidal syndromes.

Midodrine for the treatment of organic anejaculation but not spinal cord injury: a prospective randomized placebo-controlled double-blind clinical study

Anejaculation is a rare cause of infertility and adversely affects the general sense of well-being and perception of sexual life satisfaction. Evidence to support effective and noninvasive treatment for this ejaculatory disorder is lacking. This study aimed to evaluate the efficacy and safety of midodrine (alpha(1)-adrenergic receptor agonist) for the treatment of organic anejaculation but not spinal cord injury (SCI). A total of 128 patients were randomly assigned to oral midodrine 7.5-15 mg per day in a stepwise approach (group 1, n=64), or a similar regimen of placebo (group 2, n=64). They underwent a complete physical examination, echocardiography, 12-lead electrocardiogram, transrectal ultrasonography, complete blood count and blood chemistry. Hormonal assays included serum levels of luteinizing hormone, follicle-stimulating hormone, prolactin and testosterone. To rule out other sexual dysfunction, patients also completed the International Index of Erectile Function questionnaire. Psychiatric disorders were excluded by appropriate tests. Outcome measure was reversal of the anejaculation. None of the patients in the placebo group achieved antegrade or retrograde ejaculation. At the end of study, antegrade, retrograde and antegrade+retrograde ejaculation occurred in 18 (29.5%), 8 (13.1%) and 9 (14.8%) patients in midodrine group, respectively (all P=0.01). The most and least favorable responses were among patients with multiple sclerosis and bilateral sympathectomy, respectively. Midodrine improved ejaculation function in a dose-dependent manner. Four participants (6.3%) in midodrine group discontinued this study for reasons of adverse events. In patients with organic anejaculation but without SCI midodrine can reverse anejaculation in more than 50% of patients. Further studies are needed, however, for the evaluation of different treatment regimens in anejaculation therapy.

alpha-Adrenoceptor agonists for the treatment of vasovagal syncope: a meta-analysis of worldwide published data

AIM

The present study was aimed at evaluating present randomized controlled trials (RCTs) regarding the effect of alpha-adrenoceptor agonists on vasovagal syncope (VVS).

METHODS

According to inclusion and exclusion criteria, articles were selected from medical electronic databases. RCTs were then assessed based on the Juni assessment, and meta-analysis was completed using the Review Manager 4.2 software. Indication to further evaluate effects was the recurrence of syncope during follow-up treatment or a response in the head-up tilt test (HUT) after treatment. The results were stated as odd ratio (OR), with a 95% confidence interval (CI) and a p < 0.05 significant level.

RESULTS

In total, six RCTs were selected. Funnel plot analysis showed possible publication bias. Meta-analysis of the six RCTs, including all 165 patients in the treatment group and 164 patients in the control group, indicated that alpha-adrenoceptor agonists were more effective than placebos in treating VVS (OR = 0.21, 95% CI: 0.06-0.77, p = 0.02). The further, weighted independent t-test disclosed that the weighted mean percentage of responders for midodrine (76.3%+/- 7.7%) was significantly higher than that for etilefrine (65.5%+/- 15.4%) (t = 5.863, p < 0.001).

CONCLUSION

The currently published RCTs support that alpha-adrenoceptor agonists might be effective for VVS. Midodrine can be regarded as a better choice compared with etilefrine.