Muscle relaxants are medicines that block transmission of nerve
impulses to the muscles. They sometimes are also referred to as neuromuscular
blocking agents. These medicines are often used during
anesthesia but do not usually affect consciousness and
do not provide pain relief (analgesia). They are given through a vein (intravenously).
Some general anesthetics also cause some muscle relaxation. But
in many cases a second medicine will be used during anesthesia to relax
muscle tone throughout your body or to relax specific muscles. For example, a
muscle relaxant may be used to relax muscles in the abdomen or chest for
surgery in those parts of the body, relax eye muscles in certain kinds of eye
surgery, or permit easy movement of joints during bone and joint surgery.
Muscle relaxants are also used routinely during the insertion of an
endotracheal (ET) tube to relax the muscles in the
neck and throat, which reduces the risk of injury. They may also be used to
relax the chest muscles when an endotracheal tube is used to help a person
breathe (mechanical ventilation).