Drug Groups

approved

Description

An intravenous anesthetic with a short duration of action that may be used for induction of anesthesia. [PubChem]

Indication

Methohexital is indicated for use as an intravenous anaesthetic. It has also been commonly used to induce deep sedation.

Pharmacology

Methohexital, a barbiturate, is used for the induction of anesthesia prior to the use of other general anesthetic agents and for induction of anesthesia for short surgical, diagnostic, or therapeutic procedures associated with minimal painful stimuli. Little analgesia is conferred by barbiturates; their use in the presence of pain may result in excitation.

Toxicity

The onset of toxicity following an overdose of intravenously administered methohexital will be within seconds of the infusion. If methohexital is administered rectally or is ingested, the onset of toxicity may be delayed. The manifestations of an ultrashort-acting barbiturate in overdose include central nervous system depression, respiratory depression, hypotension, loss of peripheral vascular resistance, and muscular hyperactivity ranging from twitching to convulsive-like movements. Other findings may include convulsions and allergic reactions. Following massive exposure to any barbiturate, pulmonary edema, circulatory collapse with loss of peripheral vascular tone, and cardiac arrest may occur.

Affected Organisms

Biotransformation

Metabolism occurs in the liver through demethylation and oxidation. Side-chain oxidation is the most important biotransformation involved in termination of biologic activity.

Absorption

The absolute bioavailability following rectal administration of methohexital is 17%.

Half Life

5.6 ± 2.7 minutes

Protein Binding

73%

Elimination

Excretion occurs via the kidneys through glomerular filtration.

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