Abstract

UNMASKING AN OLD DRUG – POLYMYXIN B AND HYPOTENSION: A CASE SERIES

Minchu Arunkumar Sunkadakatte* and Dr. Pooja Prathapan Sarada

ABSTRACT

The emergence of multidrug-resistant (MDR) gram-negative bacteria has led to an increased risk of hospital-acquired infections, posing significant public health concern, with expected rising mortality rates by 2050. Polymyxins, first discovered in the late 1940s, have regained clinical importance due to their efficacy against these resistant pathogens, despite being abandoned in the 1970s due to nephrotoxicity and neurotoxicity. Recent resurgence in polymyxin use has occurred due to the limited options for treating resistant infections. However, while nephrotoxicity and neurotoxicity are well-documented, hypotension as a side effect has not been widely recognized. This case series presents five patients who developed hypotension shortly after Polymyxin B infusion. In all cases, blood pressure dropped within 30 to 60 minutes of administration, and appropriate clinical measures, including drug withholding, fluid resuscitation, and vasopressor use, were undertaken to stabilize blood pressure. Despite treatment, onepatient could not be revived. The mechanism behind this hypotension may be related to polymyxin-induced histamine release, endothelial disruption, or alteration in vascular smooth muscle tone. Polymyxin B-induced hypotension is not noted in standard pharmacology resources, suggesting this adverse effect is under-recognized. The exact incidence and risk factors for this side effect remain unclear. Further studies are needed to explain the relationship between polymyxin B and hypotension, identify high-risk patients, and develop strategies to prevent this complication. Clinicians should be aware of this potential adverse effect, particularly in critically ill patients, and monitor hemodynamic parameters closely during polymyxin B administration.

Keywords: Polymyxin B, Hypotension, MDR infections, Blood pressure.