Filling syringe. Gloved hand filling a hypodermic syringe from a vial of Xylocaine, a local anaesthetic. The syringe and needle will be used to inject the drug directly into the area to be anaesthetised. Anaesthetics prevent pain during examination, treatment or surgery. Xylocaine contains lignocaine hydrochloride, one of the most widely used local anaesthetics, along with adrenaline. Adrenaline is a vasoconstrictor, reducing blood flow and therefore prolonging the local effect of the anaesthetic. Rubber gloves help to maintain a sterile environment.