Sodium oxybate

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An endogenous 4-carbon fatty acid. Neurotransmitter in the regulation of sleep, haemodynamics, emotion and memory.

Sedative with a major paradoxical indication of being a drug of choice in cataplexy although its effectiveness is not absolute and unpredictable.

Also used as a drug of abuse.


Clinical Use


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CD:Schedule 2 initiated by and remain under the guidance of a physician experienced in the treatment of sleep disorders. Expensive as a therapy goes. Presently rarely commissioned by NHS. An exception outwith the usual commissioning rules has been made by the DoH to allow for private prescriptions in cases of Pandemrix® influenza vaccine associated cataplexy. As of 2016 access on the NHS is usually through the individual funding request route sometimes backed by the courts[1]


Oral 2.25g taken upon going to bed and again about 2.5 to 4 hours later. Titrate to effect in dose increments of 1.5 g/day every week or so to a maximum of 9 g/day.

Clinical Issues

  • As respiratory depressant doses over 6g/day should be stringently evaluated in patients with concomitant sleep apnoea. Its use of monotherapy may be more dangerous as most patients in clinical trials were also on a CNS stimulant.
  • No head to head data with clomipramine
  • Cost effectiveness is low at 2015 prices


Cautions and Interactions

Has sympathomimetic effects.[2]

Side effects

Special advice

CNS depressant.


Colourless oily liquid. Gamma-butyrolactone (GBL), another drug of abuse, is a precursor to gamma-hydroxybutyrate.

Issues in substance abuse context

As of 2016 one of common drugs of abuse in UK because of relative cheapness and availability. It has a narrow therapeutic index between the desired euphoria/disinhibition/increased confidence and depression manifest as coma (G coma) with further risk of cardiac and respiratory depression. Treatment is supportive with benzodiazepines for agitation. Regular uses can be taking it every few hours.


Chronic abusers can have a very severe withdrawal reaction with hallucinosis, agitation and tremor. In adults very large doses of benzodiazepines may be required, with typical initial doses of diazepam of 20mg and up to 180mg/24 hours as inpatient. [[Baclofen] 10mg up to tds may also be indicated[3]. Indeed baclofen may be used to prevent relapse[4]. Some community withdrawal regimes have used up to 50mg/24 hours without respiratory depression issues.