been done is nausea and vomiting, not pain. So let's talk
a little bit about some of the other drugs.
The most effective anti-anxiety medications we have
are benzodiazepines. These are drugs
such as, Valium is the one
that people remember, that's
an older drug. Currently we use
midazolam and lorazepam primarily.
We used to use these drugs as part of a pre-med,
before the patient came to surgery, an hour or two
before surgery. But this is largely been abandoned
much to everyone's surprise. Patients
found the sedation and the often accompanying amnesia
associated with these drugs, to be unpleasant.
With very anxious patients, a drug
such as midazolam, will bring some
relief prior to induction of anesthesia. Plus the amnestic
effect usually associated with the medication
may reduce the possibility
of recall during anesthesia.
These agents are generally utilized as sleep
aids or anti-anxiety medications,
and are not widely used for patients who
are going to receive general anesthesia.
They are very effective however improving anxiety levels
when patients are undergoing regional anesthesia
or surgery under local anesthetic injection. So we're
now going to talk about local anesthetics. Local
anesthetics are used both in just infiltration
of the skin or other tissue areas,
so the surgeon can work on them, but more
commonly are used in a regional format
where a block is used to anesthetize
a group of nerves, a plexus of nerves
so that more than one area is affected at the same
time. So when the dentist gives you
local anesthetic in your mouth, he or she
is actually not just infiltrating the gums,
they're actually blocking a series
of nerves that enter your face, and that's
a regional block, that's not really a local infiltration.
So your whole face is numb, not
just one tooth. Ester local anesthetics, are the oldest
of these drugs, and they include drugs such as
cocaine. Yes, it's a local anesthetic. Procaine,
tetracaine and many others. They are characterized
by having an ester link that
is metabolized like Succinylcholine
by Pseudocholinesterase. So they're broken down
by Pseudocholinesterase. They often have
a core configuration of para-amino
benzoic acid, PABA, same as sunscreens. And
this PABA is associated with a high incidence
of allergic reactions and anaphylaxis,
which is the most severe type of allergic reactions.
So Ester anesthetics are rarely used by modern
anesthesiologists. The other type of local anesthetic
is an amide local anesthetic and this is the more modern
type of drug. And you can always differentiate between
an ester and a amide local anesthetic by knowing
its generic name. If there is no 'i' before
the 'caine' in the generic name,
it's a ester. If there is an 'i',
then it's an amide. So think
of lignocaine or lidocaine, 'i' comes before
a 'caine', ropivicaine, there's an 'i' before a 'caine',
bupivicaine, there's an 'i' before a 'caine',
cocaine, no 'i' before a 'caine' so it's an ester.
Amide local anesthetics such as lidocaine, which is also
known as lignocaine, bupivicaine, ropivicaine,
mepivicaine, and others, are preferred for regional
anesthesia of all kinds because they are
predictable in their onset and duration of action,
and they virtually never produce allergic reactions.
So in summary, in this lecture we've talked about
the management of acute pain, surgical
pain, trauma pain. We've talked about
addiction and tolerance to opiates.
We've talked about sedation with sedating drugs.
We've talked about the incidence and
the treatment or prevention of post-operative
nausea and vomiting. And we've talked a little bit
about regional anesthesia, and we'll talk more about that
in a future slide. All the drugs that I've mentioned, must
be well recognized by every anesthesiologist
who must, in addition to understanding
how to use them, understand the potential
for side effects and how to manage
side effects when they occur.