A review on the clinical pharmacokinetics of hydralazine

Vasoplegic syndrome during heart transplantation: A systematic review and meta-analysis

BACKGROUND

Vasoplegic syndrome (VS) is a common occurrence during heart transplantation (HT). It currently lacks a uniform definition between transplant centers, and its pathophysiology and treatment remain enigmatic. This systematic review summarizes the available published clinical data regarding VS during HT.

METHODS

We searched databases for all published reports on VS during HT. Data collected included the incidence of VS in the HT population, patient and intraoperative characteristics, and postoperative outcomes.

RESULTS

Twenty-two publications were included in this review. The prevalence of VS during HT was 28.72% (95% confidence interval: 27.37%, 30.10%). Factors associated with VS included male sex, higher body mass index, hypothyroidism, pre-HT left ventricular assist device or venoarterial extracorporeal membrane oxygenation (VA-ECMO), pre-HT calcium channel blocker or amiodarone usage, longer cardiopulmonary bypass time, and higher blood product transfusion requirement. Patients who developed VS were more likely to require postoperative VA-ECMO support, renal replacement therapy, reoperation for bleeding, longer mechanical ventilation, and a greater 30-day and 1-year mortality.

CONCLUSIONS

The results of our systematic review are an initial step for providing clinicians with data that can help identify high-risk patients and avenues for potential risk mitigation. Establishing guidelines that officially define VS will aid in the precise diagnosis of these patients during HT and guide treatment. Future studies of treatment strategies for refractory VS are needed in this high-risk patient population.

Physiologic Treatment of Severe Hypertension in Pregnancy and Postpartum

We aimed to evaluate physiologic treatment of severe hypertension. This was a retrospective cohort study of pregnant and postpartum patients with severe hypertension (systolic blood pressure [BP] 160 mm Hg or higher or diastolic BP 110 mm Hg or higher) treated with intravenous labetalol or hydralazine at a single tertiary care center between 2013 and 2018. Patients were classified as having physiologic treatment if they had hyperdynamic physiology (pulse pressure 65 mm Hg or higher) and received labetalol or had vasoconstrictive physiology (diastolic BP 100 mm Hg or higher) and received hydralazine. The primary outcome was number of antihypertensive doses to achieve nonsevere BP. Of 1,120 patients included in the analysis, 653 had physiologic treatment and 467 had nonphysiologic treatment, with 16 (1.4%) excluded for inability to classify physiology. Physiologic treatment was associated with fewer antihypertensive doses (1.4±0.9 doses vs 1.6±1.4 doses; adjusted β -0.28, 95% CI, -0.42 to -0.14) and lower odds of medication conversion (2.5% vs 4.7%; adjusted odds ratio 0.48, 95% CI, 0.24-0.93) but no difference in time to nonsevere BP (31 minutes [interquartile range 16-66 minutes] vs 34 minutes [interquartile range 15-76 minutes]; adjusted hazard ratio 1.0, 95% CI, 0.9-1.2). Physiologic treatment of severe hypertension warrants further evaluation.

Antimicrobial activity of hydralazine against methicillin-resistant and methicillin-susceptible Staphylococcus aureus

Background: Staphylococcus aureus is a human pathogen responsible for high mortality rates. The development of new antimicrobials is urgent. Materials & methods: The authors evaluated the activity of hydralazine along with its synergism with other drugs and action on biofilms. With regard to action mechanisms, the authors evaluated cell viability, DNA damage and molecular docking. Results: MIC and minimum bactericidal concentration values ranged from 128 to 2048 μg/ml. There was synergism with oxacillin (50%) and vancomycin (25%). Hydralazine reduced the viability of biofilms by 50%. After exposure to hydralazine 2× MIC, 58.78% of the cells were unviable, 62.07% were TUNEL positive and 27.03% presented damage in the comet assay (p < 0.05). Hydralazine showed affinity for DNA gyrase and TyrRS. Conclusion: Hydralazine is a potential antibacterial.

Hydralazine Revives Cellular and Ocular Lens Health-Span by Ameliorating the Aging and Oxidative-Dependent Loss of the Nrf2-Activated Cellular Stress Response

A major hallmark of aging-associated diseases is the inability to evoke cellular defense responses. Transcriptional protein Nrf2 (nuclear factor erythroid-derived 2-related factor) plays a pivotal role in the oxidative stress response, cellular homeostasis, and health span. Nrf2's activation has been identified as a therapeutic target to restore antioxidant defense in aging. Here, we demonstrated that FDA-approved drug, hydralazine (Hyd), was a reactivator of the Nrf2/ARE (antioxidant response element) pathway in various ages and types of mouse (m) or human (h) lens epithelial cells (LECs) and mice lenses in-vitro/in-vivo. This led to Hyd-driven abatement of carbonyls, reduced reactive oxygen species (ROS), and reduced 4-HNE/MDA-adducts with cytoprotection, and extended lens healthspan by delaying/preventing lens opacity against aging/oxidative stress. We elucidated that Hyd activated the protective signaling by inducing Nrf2 to traverse from the cytoplasm to the nucleus and potentiated the ARE response by direct interaction of Nrf2 and ARE sequences of the promoter. Loss-of-function study and cotreatment of Hyd and antioxidant, N-acetyl cysteine (NAC) or Peroxiredoxin (Prdx)6, specified that Nrf2/ARE-driven increase in the promoter activity was Hyd-dependent. Our study provides proof-of concept evidence and, thereby, paves the way to repurposing Hyd as a therapeutic agent to delay/prevent aging and oxidative-related disorders.