Intravenous (IV) anesthetic medications are given into
a vein. Medications can be given quickly and are rapidly absorbed into the
bloodstream.
Intravenous anesthetic medications are used to relieve pain
(analgesia), to relax (sedate), to induce sleepiness (hypnosis) or
forgetfulness (amnesia), or to make you unconscious for general anesthesia.
Most IV anesthetics cannot produce all of these effects on their own. An IV
anesthetic is often combined with another IV anesthetic or with an inhalant
(vaporized liquid) anesthetic.
Intravenous anesthetics include barbiturates, benzodiazepines,
propofol, opioids, and other medications.
Barbiturates
Barbiturates used for anesthesia include sodium thiopental
(Pentothal) and methohexital (Brevital). These fast-acting medications are
sometimes used for general anesthesia induction.
Benzodiazepines
Benzodiazepines cause sedation, sleepiness, forgetfulness, and
unconsciousness. In higher doses they also produce muscle relaxation. The most
commonly used benzodiazepine is midazolam (Versed). Benzodiazepines may be used
to provide sedation and amnesia during
local or regional anesthesia or during procedural
sedation, which combines the use of local anesthesia with sedatives to relax
you for minor procedures.
These medications can also be given orally (as a pill) as a
premedication before anesthesia to help relieve anxiety.
Propofol
The first phase of anesthesia, when an anesthetic is first given,
is called induction. Propofol is the most commonly used anesthetic induction
agent. It causes rapid and reversible decrease in consciousness with minimal,
if any, aftereffects.
Opioids
Opioids are medications that can reduce the sensation of pain and
cause deep sleep. Many opioids are used in anesthesia, primarily to relieve
pain. Since they cause some sedation and sleepiness, they may reduce the need
for other sedative-hypnotic medications during anesthesia. However, opioids by
themselves are generally not used for anesthesia, because there have been
reported cases of awareness during anesthesia when opioids alone were used as
anesthetics.
Opioids also may be used for pain relief after surgery.
Opioids commonly used for anesthesia include fentanyl (Sublimaze),
alfentanil (Alfenta), sufentanil (Sufenta), remifentanil, morphine, and
meperidine (Demerol).
Opioids affect breathing but at usual doses have only minor effects
on the cardiovascular system. At higher doses, however, opioids may affect
heart rate and blood pressure. Opioids may be associated with nausea and
vomiting after surgery. They may also cause constipation, difficulty urinating,
and itching of the skin. Allergic reactions are rare.