The oral LD₅₀ in rats is 9690 mg/kg.^L42640

There are several cases of GHB overdose in literature where individuals ingested GHB illicitly in conjunction with other drugs and alcohol. These individuals exhibited varying degrees of depressed consciousness that may fluctuate rapidly between a confusional, agitated, combative state with ataxia and coma. Emesis (even when obtunded), diaphoresis, headache, and impaired psychomotor skills have been observed. No typical pupillary changes have been described to assist in diagnosis; pupillary reactivity to light is maintained. Blurred vision has been reported. An increasing depth of coma and acidosis have been observed at higher doses. Myoclonus and tonic-clonic seizures have been reported. Respiration may be unaffected or compromised in rate and depth. Cheyne-Stokes respiration and apnea have been observed. Bradycardia and hypothermia may accompany unconsciousness, as well as muscular hypotonia, but tendon reflexes remain intact.^L30598

In clinical trials, two adults experienced sodium oxybate overdose. One patient received an estimated dose of 150 g, which was more than 15 times the maximum recommended dose: this patient became unresponsive with brief periods of apnea and incontinent of urine and feces. The patient recovered without sequelae. The other patient died following a multiple drug overdose consisting of sodium oxybate and numerous other drugs.^L30598

There is no known antidote for sodium oxybate; therefore, overdose should be managed with general symptomatic and supportive care, with a consideration of gastric decontamination if co-ingestants are suspected.^L30598