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

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.

Midodrine initiation criteria, dose titration, and adverse effects when administered to treat shock: A systematic review and semi-quantitative analysis

Objective

Systematically examine the literature describing midodrine to treat shock and to summarize current administration and dosing strategies.

Data sources

Structured literature search conducted in MEDLINE (PubMed) from inception through May 10, 2023.

Study Selection and Data Extraction

Abstracts and full texts were assessed for inclusion by two blinded, independent reviewers. English-language publications describing use of midodrine in adult patients with shock were included. Data were extracted by two blinded, independent abstractors using a standardized extraction tool. Quality assessments were completed by paired reviewers using JBI methodology.

Data Synthesis

Fifteen of 698 (2%) screened manuscripts were included with 1,714 patients with a variety of shock types. Seven studies (47%) were retrospective, two (13%) prospective observational, and six (40%) randomized controlled studies. Midodrine was initiated to facilitate intravenous vasopressor (IVP) weaning in most (11, 73%) studies; only two (13%) reported IVP weaning protocol use. Starting doses were 10 mg every 8 hours (4, 27%) or three times a day (3, 20%), 20 mg every 8 hours (2, 13%); six studies (40%) did not report initial midodrine dosing. A midodrine titration protocol was reported in 6 (40%) studies. Thirteen (87%) studies evaluated for bradycardia, identified in 6 (46%) studies among 204 patients; only one (0.5%) patient required midodrine discontinuation. Three (20%) studies reported on hypertension with an incidence of 7-11%. Four (27%) studies assessed for ischemia; 5/1128 (0.4%) patients experienced mesenteric ischemia requiring midodrine discontinuation.

Relevance to Patient care and Clinical Practice

This review explores the pragmatic details involved in initiating, titrating, and weaning midodrine for the bedside clinician and identifies rates of adverse events and complications.

Conclusions

Published literature describing midodrine use for shock is heterogeneous and comprised primarily of low or very low quality data. Future controlled trials addressing the shortcomings identified in this systematic review are warranted.

Oral blood pressure augmenting agents for intravenous vasopressor weaning

Intravenous (IV) vasopressors are essential in the management of hypotension and shock. Initiation of oral vasoactive agents to facilitate weaning of IV vasopressors to liberate patients from the intensive care unit is common despite conflicting evidence regarding the benefits of this practice. While midodrine appears to be the most frequently studied oral vasoactive agent for this purpose, its adverse effect profile may preclude its use in certain populations. In addition, some patients may require persistent use of IV vasopressors for hypotension refractory to midodrine. The use of additional and alternative oral vasoactive agents bearing different mechanisms of action is emerging. This article provides a comprehensive review of the pharmacology, clinical uses, dosing strategies, and safety considerations of oral vasoactive agents and their application in the intensive care setting.

Evaluation of Oral Vasoactive Medications to Maintain Mean Arterial Pressure in Spinal Cord Injury

INTRODUCTION

An acute spinal cord injury (SCI) results in significant morbidity worldwide. Guidelines recommend mean arterial pressure (MAP) augmentation to prevent hypoperfusion. Although there is no consensus on a single vasoactive agent for MAP augmentation, intravenous vasopressors are commonly utilized, requiring an intensive care unit (ICU). Beyond the financial burden for patients, ICU stays require significant hospital system resource utilization. Oral vasoactive agents, such as pseudoephedrine and midodrine, are also utilized for MAP augmentation, but little data on their efficacy are available. This study investigates the use and dosing of oral vasoactive agents as an alternative in MAP augmentation in SCI.

MATERIALS AND METHODS

Adult SCI patients were retrospectively investigated. Total daily vasoactive dose, treatment efficacy, and ICU length of stay were evaluated.

RESULTS

141 patients were evaluated, with 7.1% receiving oral agents alone, and 80.9% receiving vasopressors who either transitioned to pseudoephedrine, pseudoephedrine plus midodrine, or no oral agent. Patients receiving oral agents trended toward decreased ICU stay, but there was no difference in vasopressor duration. Similar MAP goal success rates were found between groups. A variety of initial and maximum daily doses of PO agents were used. Median doses were 120 mg pseudoephedrine and 30 mg midodrine. Early initiation of pseudoephedrine resulted in shorter ICU stays.

CONCLUSIONS

This study demonstrated shorter ICU length of stay and similar MAP goal success with PO agents as compared to vasopressors. This may indicate these medications could be utilized to decrease the financial burden placed on patients and the health care system from lengthy ICU courses. This study is limited by a small sample size and variable agent dosing.

The Impact of Midodrine Tapering Versus Nontapering Regimens on the Clinical Outcomes of Critically Ill Patients: A Retrospective Cohort Study

BACKGROUND

Midodrine has been used in the intensive care unit (ICU) setting to reduce the time to vasopressor discontinuation. The limited data supporting midodrine use have led to variability in the pattern of initiation and discontinuation of midodrine.

OBJECTIVES

To compare the effectiveness and safety of 2 midodrine discontinuation regimens during weaning vasopressors in critically ill patients.

METHODS

A retrospective cohort study was conducted at King Abdulaziz Medical City. Included patients were adults admitted to ICU who received midodrine after being unable to be weaned from intravenous vasopressors for more than 24 hours. Patients were categorized into two subgroups depending on the pattern of midodrine discontinuation (tapered dosing regimen vs. nontapered regimen). The primary endpoint was the incidence of inotropes and vasopressors re-initiation after midodrine discontinuation.

RESULTS

The incidence of inotropes or vasopressors' re-initiation after discontinuation of midodrine was lower in the tapering group (15.4%) compared with the non-tapering group (40.7%) in the crude analysis as well as regression analysis (odd ratio [OR] = 0.15; 95% CI = 0.03, 0.73, P = 0.02). The time required for the antihypertensive medication(s) initiation after midodrine discontinuation was longer in patients who had dose tapering (beta coefficient (95% CI): 3.11 (0.95, 5.28), P = 0.005). Moreover, inotrope or vasopressor requirement was lower 24 hours post midodrine initiation. In contrast, the two groups had no statistically significant differences in 30-day mortality, in-hospital mortality, or ICU length of stay.

CONCLUSION AND RELEVANCE

These real-life data showed that tapering midodrine dosage before discontinuation in critically ill patients during weaning from vasopressor aids in reducing the frequency of inotrope or vasopressor re-initiation. Application of such a strategy might be a reasonable approach among ICU patients unless contraindicated.

Exploring the Efficacy of Midodrine for Tapering Off Vasopressors

Sepsis and septic shock represent critical conditions, often necessitating vasopressor support in the intensive care unit (ICU). Midodrine, an oral vasopressor, has gathered attention as a potential adjunct to vasopressor therapy, aiming to facilitate weaning and improve clinical outcomes. However, the efficacy of midodrine remains questionable, with conflicting evidence from clinical trials and meta-analyses. This article provides a comprehensive review of the literature on midodrine's role in ICU settings by gathering evidence from multicenter trials, retrospective studies, and meta-analyses. While some studies suggest a limited benefit of midodrine in expediting vasopressor weaning and reducing ICU/hospital stays, others report potential advantages, particularly in reducing mortality rates among septic shock patients. Ongoing efforts aim to address knowledge gaps surrounding midodrine's efficacy and safety.