γ-hydroxybutyric acid

(GHB) butyric acid substituted at the γ, or 4, position; it is an intermediate in the metabolism of γ-aminobutyric acid (GABA) and with GABA occurs at elevated levels in some body fluids in succinate semialdehyde dehydrogenase deficiency (q.v.). Because of its sedative and central nervous system depressant properties, this substance has become a drug of abuse; when taken with ethanol it causes respiratory depression and coma that can be fatal. Called also 4-h. a. and succinate semialdehyde.