What is the concentration of epinephrine added to local anesthetic solution-

Epinephrine 1:200,000 or 5 microg/ml may be added to local anesthetic solution to produce vasoconstriction. Epinephrine is used along with local anesthetics at a concentration of 5 mg/mL or 1:200,000. At this dose, epinephrine provides adequate vasoconstriction. It is added to local anesthetics to limit systemic absorption and the systemic side effects. It limits the diffusion of the drug away from the site thereby prolongs the duration of block and improves the depth of anesthesia. Epinephrine is also used to detect accidental intraaerial injection of a local anesthetic during the neuraxial block. The classic test dose combines local anesthetic and epinephrine, 3 mL of 1.5% lidocaine with 1:200,000 epinephrine. This epinephrine if injected intraaerially would increase the hea rate by 20% with or without the rise in blood pressure. Use of epinephrine can also enhance analgesia by acting on spinal a2 adrenergic receptors. The extent to which epinephrine prolongs the duration of anesthesia depends on the specific local anesthetic used and the site of injection. It can prolong the block caused by shoer acting agents as compared to longer acting ones. i.e. by adding epinephrine to lidocaine, the duration of the block is prolonged significantly than by the addition of epinephrine to bupivacaine.