Methohexital

Absorption

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

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.

The Uses of Methohexital

Methohexital is a short-acting barbiturate used as a sedative. Methohexital is used an anesthetic for oral surgery and dentistry and is also used to induce anesthesia prior to electroconvulsive therapy (ECT). Methohexital is a Controlled Substance.

Indications

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

Background

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

Definition

ChEBI: A barbiturate, the structure of which is that of barbituric acid substituted at N-1 by a methyl group and at C-5 by allyl and 1-methylpent-2-ynyl groups.

Pharmacokinetics

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.

Metabolism

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