Prilocaine is an amide and has similar indications to lidocaine but is most frequently used for intravenous regional anaesthesia.
Prilocaine is the most rapidly metabolised amide local anaesthetic, with metabolism occurring not only in the liver, but also in the kidney and lung.
Bier block anaesthesia is an intravenous regional anesthesia technique in which an extremity (generally an arm) is made numb for surgery by injecting a local anaesthetic solution into a vein after the blood has been squeezed out of the extremity and a tourniquet has been placed on it. The tourniquet prevents a potentially toxic dose of local anaesthetic from leaving the extremity and blood from entering it, giving the patient an anaesthetised extremity and the surgeon a bloodless field to work in.
A eutetectic mixture is one in which two substances are mixed to produce a substance which behaves with a single set of physical characteristics.
Lidocaine/prilocaine is a eutectic mixture of equal quantities (by weight) of lidocaine and prilocaine. A 5% emulsion preparation, containing 2.5% each of lidocaine/prilocaine, is marketed by APP Pharmaceuticals under the trade name EMLA (an abbreviation for eutectic mixture of local anaesthetic).
EMLA should be avoided in patients with congenital or aquired methaemoglobinaemia.