Last week we started this three part series with inhalation anesthetics, and here is a link. This week we shall discuss injected anesthetics, and finally shall finish up the series next week with local ones.
We should once again stress the difference betwixt anesthetics and analgesics. In general (this rule is not 100%, but darned close), anesthetics render the patient unconscious so that surgical procedures can be performed with no physical pain during the procedure. In addition, many anesthetics cause muscle relaxation which makes surgical procedures less traumatic.
Analgesics, on the other hand, are not designed to render the patient unconscious, but rater to moderate the sensation of pain caused by many reasons. A few analgesics can be used as anesthetics, but in general depress the medulla such that respiratory difficulties often result.