Methylene Blue in Vasoplegic Shock in Renal Transplant Recipients: A Case Series

Abstract Introduction: Vasoplegic syndrome (VS) is a distributive shock characterized by profound hypotension, low systemic vascular resistance, and inadequate response to conventional vasopressors. While commonly observed in cardiac surgery, its occurrence in renal transplant settings is rare. Methylene blue (MB), through inhibition of the nitric oxide–cyclic GMP pathway, has shown promise in managing vasoplegia by restoring vascular tone. Methods: We report two cases of vasoplegic shock managed with MB. The first case involved a patient who developed intraoperative vasoplegic shock during an ABO-compatible renal transplant. The second case involved a renal transplant recipient who presented two years post-transplant with septic shock and vasoplegia, refractory to high-dose vasopressors. Both patients were administered intravenous MB (1 mg/kg) following failure of standard therapy. Additionally, a review of literature was conducted to explore the clinical application, timing, and outcomes of MB use in vasoplegic shock. Results: In both cases, MB administration led to a significant improvement in hemodynamics, with reduction in vasopressor requirements and resolution of shock. No adverse effects attributable to MB were noted. Literature review revealed that MB is most effective when administered early (within 8 hours of shock onset), with growing evidence supporting its use in cardiac, liver transplant, and septic shock scenarios. However, reports of MB use in renal transplant patients remain sparse. Safety concerns, including potential serotonin syndrome, pulmonary vasoconstriction, and methemoglobinemia, have been noted in isolated reports but were not observed in our cases. Conclusion: These cases highlight the potential role of methylene blue as an adjunct in the management of refractory vasoplegic shock, including in the renal transplant population. While its use appears safe and effective in selected patients, further prospective studies are needed to standardize its role in transplant-associated vasoplegia.