Products
Gammahydroxybutyrate is commercially available as an oral solution (Xyrem). It has been approved in many countries since 2006. The drug belongs to narcotics and requires an aggravated prescription. GHB is also known to be manufactured and trafficked illegally.
Structure and properties
The free γ-hydroxybutyric acid (C4H8O3, Mr = 104.1 g/mol) is a colorless and odorless liquid. In the drug, it is in the form of the sodium salt sodium oxybate, a white crystalline powder that is highly soluble in water. GHB is a γ-hydroxylated butyric acid that is structurally closely related to the neurotransmitter GABA (γ-aminobutyric acid). GHB has been shown to be an endogenous substance found in the brain and elsewhere.
Effects
Gammahydroxybutyrate (ATC N07XX04) has central depressant, sleep-inducing, and sedative properties. In narcolepsy, it improves sleep structure and reduces daytime sleepiness. GHB has a short half-life of about 30 to 60 minutes and a duration of action of up to three hours. Effects occur after about 15 minutes. The effects are based on interaction with receptors (e.g., GABAB receptor) and neurotransmitter systems (e.g., dopamine).
Indications
For the treatment of narcolepsy with cataplexy in adults. Cataplexy is sudden muscle weakness or paralysis without loss of consciousness that usually occurs in response to an emotional trigger. In other countries, GHB has been approved for other uses. It was originally developed in the 1960s as a GABA analog and anesthetic.
Dosage
According to the SmPC. The solution is taken in bed at bedtime. A second dose is given after 2.5 to 4 hours. Therapy is started cautiously. Administration should be fasting because food reduces the bioavailability of sodium oxybate.
Abuse
GHB is abused as an intoxicant and party drug (“club drug”) because of its depressant, euphoric, disinhibitory, and aphrodisiac effects. The so-called knockout drops usually contain GHB. Like flunitrazepam, they are mixed into drinks as a “date rape drug” with the intention of sexually abusing the victims. GHB can cause amnesia, leaving victims with no memory after the assault. Therefore, drinks should not be left unattended in bars and clubs. Drinks should not be accepted from strangers.
Contraindications
- Hypersensitivity
- Succinate semial dehydrogenase defect
- Pregnancy
- Treatment with centrally depressant drugs (e.g., sleeping pills, opioids, barbiturates).
- Porphyria patients
- Liver cirrhosis
- Uncontrolled major depression
For complete precautions, see the drug label.
Interactions
Central depressant drugs and alcohol potentiate adverse effects and should not be combined with GHB. Gammahydroxybutyrate is biotransformed by gamma hydroxybutyrate dehydrogenase and corresponding interactions are possible.
Adverse effects
The most common potential adverse effects include nausea, dizziness, and headache. GHB has a narrow therapeutic range. Overdose manifestations include loss of consciousness, coma, respiratory depression, seizures, and bradycardia. Deaths associated with abuse have been reported.
