Phenylephrine versus Mephentermine in Spinal Anaesthesia- Induced Hypotension: An Updated Narrative Review

Dr. Abhijit Pradhan, Dr. Santanu Dash

Abstract: Background: A fall in blood pressure is the most frequent complication after spinal anaesthesia. This occurs mainly due to sympathetic block and may compromise tissue perfusion if not promptly recognized. Vasopressors form the cornerstone of management. Phenylephrine and mephentermine are among the commonly employed agents, but the relative clinical advantages of each remain an area of discussion. Aim: To summarize available literature comparing phenylephrine and mephentermine in the treatment of spinal anaesthesia?related hypotension, with emphasis on haemodynamic responses and adverse effects. Methods: Relevant clinical trials, comparative studies and reviews were identified from PubMed, Google Scholar and major anaesthesia journals. Studies evaluating the two drugs during spinal anaesthesia were reviewed. Haemodynamic parameters such as blood pressure, heart rate, need for rescue vasopressors and complications were examined. Results: Both vasopressors successfully restore arterial pressure during hypotensive episodes. Phenylephrine acts primarily through ??-receptor stimulation producing rapid vasoconstriction, but it is frequently associated with reflex slowing of heart rate and possible reduction in cardiac output. Mephentermine exerts both ?- and ?-adrenergic actions and tends to maintain heart rate and cardiac output, with a steadier though slightly slower pressor effect. Many studies report more bradycardia and a greater need for additional doses with phenylephrine. Conclusion: No single agent is universally superior. Phenylephrine is useful when an immediate rise in blood pressure is required or when tachycardia is undesirable. Mephentermine may be favoured when preservation of heart rate and cardiac output is a priority. Individual patient characteristics should guide drug selection.

Keywords: spinal anaesthesia, vasopressor, mephentermine, phenylephrine, hypotension

How to Cite?: Dr. Abhijit Pradhan, Dr. Santanu Dash, "Phenylephrine versus Mephentermine in Spinal Anaesthesia- Induced Hypotension: An Updated Narrative Review", Volume 14 Issue 12, December 2025, International Journal of Science and Research (IJSR), Pages: 2117-2119, https://www.ijsr.net/getabstract.php?paperid=SR251225195036, DOI: https://dx.doi.org/10.21275/SR251225195036