Phenylephrine in obstetric regional anaesthesia

We wish to raise awareness of potentially serious drug administration errors that may occur when changing to the use of phenylephrine from ephedrine as the first line vasopressor for obstetric regional anaesthesia. Recent evidence supports the use of alpha adreno-receptor agonists as an alternative, or in addition, to ephedrine for the treatment or prevention of hypotension during spinal anaesthesia for elective Caesarean section [1–4]. We are concerned, however, about the risks of changing practice en masse towards the use of potent agents that may be relatively unfamiliar to many anaesthetists. We suggest the following measures to minimise the risk: Policy change should be on a unit basis rather than an individual basis. Units should have a clear, written policy for the dilution and administration of their chosen vasopressor. We append our local regimen as an example. For phenylephrine, there may be advantages in arranging for the hospital pharmacy to supply premixed solutions. In addition, we wish to draw attention to the existence of different formulations of phenylephrine. An initial order for the supply of phenylephrine to the delivery suite from the hospital pharmacy at one of our units led to the supply of ampoules containing 50 mg of phenylephrine in 5 ml. Clearly this represented a hazard, and others should be aware of this.