1.0 2009-07-21 20:26:59 UTC 2026-05-14 16:39:54 UTC T3D2803 Methohexital SmallMolecule Methohexital belongs to the pyrimidines and pyrimidine derivatives, a subclass of diazines within the organic compounds. This exogenous compound has the formula C14H18N2O3 and an average molecular weight of 262.30 g/mol. At room temperature, it exists as a solid. It is utilized as an intravenous anaesthetic. Recorded exposure routes for the compound include intravenous, intramuscular, and rectal administration. Methohexital is found in several recorded sources, including healthcare, pharmaceuticals, and veterinary products such as hypnotics, sedatives, and anesthetics. It is also associated with electrical and electronic equipment, specifically electrically stimulated smoking devices and conductive bodies characterized by conductive materials, as well as household cleaning and consumer products such as tobacco smoke filters, cigar cigarettes, non-electric simulated smoking devices, and other smoking requisites. The compound targets the gamma-aminobutyric acid receptor subunit alpha-1 (GABRA1). Methohexital binds at a distinct binding site associated with a Cl- ionopore at the GABAA receptor, increasing the duration of time for which the Cl- ionopore is open. Consequently, the post-synaptic inhibitory effect of GABA in the thalamus is prolonged. Drug Synthetic Toxin Organic Compound Amine Amide Drug Barbiturate Anesthetic Anesthetic, Intravenous Metabolite Synthetic Compound Human Neurotoxin (+-)-5-Allyl-1-methyl-5-(1-methyl-2-pentynyl)barbituric acid 5-Allyl-1-methyl-5-(1-methyl-2-pentynyl)-2,4,6(1H,3H,5H)-pyrimidinetrione 5-Allyl-1-methyl-5-(1-methyl-pent-2-ynyl)-pyrimidine-2,4,6-trione 5-Allyl-5-(3-hexyn-2-yl)-1-methylbarbituric acid alpha-DL-1-Methyl-5-allyl-5-(1'-methylpentyn-2-yl)barbituric acid Brevital Brietal Methodrexitone Methohexitalum Methohexitone Metohexital C14H18N2O3 262.3043 262.131742452 5-(hex-3-yn-2-yl)-1-methyl-5-(prop-2-en-1-yl)-1,3-diazinane-2,4,6-trione methohexital 151-83-7 CCC#CC(C)C1(CC=C)C(=O)NC(=O)N(C)C1=O InChI=1S/C14H18N2O3/c1-5-7-8-10(3)14(9-6-2)11(17)15-13(19)16(4)12(14)18/h6,10H,2,5,9H2,1,3-4H3,(H,15,17,19) NZXKDOXHBHYTKP-UHFFFAOYSA-N Organic compounds Organoheterocyclic compounds Diazines Pyrimidines and pyrimidine derivatives Barbituric acid derivatives Azacyclic compounds Carbonyl compounds Diazinanes Dicarboximides Hydrocarbon derivatives N-acyl ureas Organic oxides Organonitrogen compounds Organopnictogen compounds 1,3-diazinane Aliphatic heteromonocyclic compound Azacycle Barbiturate Carbonic acid derivative Carbonyl group Carboxylic acid derivative Dicarboximide Hydrocarbon derivative N-acyl urea Organic nitrogen compound Organic oxide Organic oxygen compound Organonitrogen compound Organooxygen compound Organopnictogen compound Urea Ureide Aliphatic heteromonocyclic compounds acetylenic compound barbiturates Detected and Not Quantified Exogenous Membrane Methohexital Drug Metabolism Action Pathway SMP0142928 Methohexital Predicted Metabolism Pathway SMP0174661 Solid White powder. solubility 5.24e-02 g/L logp 1.8 logp 2.43 ALOGPS logs -3.70 ALOGPS solubility 5.24e-02 g/l ALOGPS logp 2.29 ChemAxon pka_strongest_acidic 8.73 ChemAxon iupac 5-(hex-3-yn-2-yl)-1-methyl-5-(prop-2-en-1-yl)-1,3-diazinane-2,4,6-trione ChemAxon average_mass 262.3043 ChemAxon mono_mass 262.131742452 ChemAxon smiles CCC#CC(C)C1(CC=C)C(=O)NC(=O)N(C)C1=O ChemAxon formula C14H18N2O3 ChemAxon inchi InChI=1S/C14H18N2O3/c1-5-7-8-10(3)14(9-6-2)11(17)15-13(19)16(4)12(14)18/h6,10H,2,5,9H2,1,3-4H3,(H,15,17,19) ChemAxon inchikey NZXKDOXHBHYTKP-UHFFFAOYSA-N ChemAxon polar_surface_area 66.48 ChemAxon refractivity 71.51 ChemAxon polarizability 27.4 ChemAxon rotatable_bond_count 5 ChemAxon acceptor_count 3 ChemAxon donor_count 1 ChemAxon physiological_charge 0 ChemAxon formal_charge 0 ChemAxon Parenteral (intramuscular, intravenous). The absolute bioavailability following rectal administration of methohexital is 17%. Methohexital binds at a distinct binding site associated with a Cl<sup>-</sup> ionopore at the GABA<sub>A</sub> receptor, increasing the duration of time for which the Cl<sup>-</sup> ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged. Metabolism occurs in the liver through demethylation and oxidation. Side-chain oxidation is the most important biotransformation involved in termination of biologic activity. Route of Elimination: Excretion occurs via the kidneys through glomerular filtration. Half Life: 5.6 &plusmn; 2.7 minutes No indication of carcinogenicity to humans (not listed by IARC). Methohexital is indicated for use as an intravenous anaesthetic. It has also been commonly used to induce deep sedation. It is only used in hospital or similar settings, under strict supervision. #<HealthEffect::ActiveRecord_Associations_CollectionProxy:0x00007f72237c35c0> 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. Establish an airway and ensure oxygenation and ventilation. Resuscitative measures should be initiated promptly. For hypotension, intravenous fluids should be administered and the patient's legs raised. If desirable increase in blood pressure is not obtained, vasopressor and/or inotropic drugs may be used as dictated by the clinical situation. For convulsions, diazepam intravenously and phenytoin may be required. If the seizures are refractory to diazepam and phenytoin, general anesthesia and paralysis with a neuromuscular blocking agent may be necessary. Protect the patient's airway and support ventilation and perfusion. Meticulously monitor and maintain, within acceptable limits, the patient's vital signs, blood gases, serum electrolytes, etc. Absorption of drugs from the gastrointestinal tract may be decreased by giving activated charcoal, which, in many cases, is more effective than emesis or lavage; consider charcoal instead of or in addition to gastric emptying. Repeated doses of charcoal over time may hasten elimination of some drugs that have been absorbed. Safeguard the patient's airway when employing gastric emptying or charcoal. (L1712) DB00474 HMDB14617 9034 CHEMBL7413 8683 C07844 102216 Methohexital Methohexital 1156027 Drugs.com: http://www.drugs.com/cons/Methohexital.html RxList: The Internet Drug Index (2009).: http://www.rxlist.com/ BE0000795 Methohexital binds at a distinct binding site associated with a Cl<sup>-</sup> ionopore at the GABA<sub>A</sub> receptor, increasing the duration of time for which the Cl<sup>-</sup> ionopore is open. The post-synaptic inhibitory effect of GABA in the thalamus is, therefore, prolonged.