Gamma-hydroxybutyrate (GHB) or gamma-hydroxybutyric acid is an illegal drug, as well as a naturally-occurring chemical in the brain. It is used medically as a general anaesthetic and to treat insomnia, narcolepsy and alcoholism. It has also been used to treat depression and to improve athletic performance.

When used as a recreational drug, GHB brings about feelings of euphoria, increased confidence, intoxication and sexual arousal. These effects usually last between one and three hours. Some bodybuilders also use GHB, as it is thought to induce the type of sleep during which muscle tissue is built up. It is usually available as a powder, which is dissolved in liquid and drunk.

GHB can also cause nausea, vomiting, dizziness, drowsiness, agitation, unusual behaviour and loss of memory. In high doses, GHB can cause unconsciousness, depressed breathing and unconsciousness. However, a small dose increase above that needed to induce a ‘high’ can sometimes cause unconsciousness. The risk of this is increased if it is taken with alcohol or other depressant drugs. For this reason, GHB is considered a ‘date rape’ drug.

GHB is addictive. However, most cases of dependence have been seen in people using the drug repeatedly, usually as an aid to sleep.

Other chemicals that can be converted into GHB in the body include gamma-butyrolactone (GBL) and 1,4-butanediol.

One case of elevated GHB levels in a man taking ritonavir (Novir)-boosted saquinavir (Invirase) has been reported^[1]. This has led to concern that protease inhibitors can inhibit the breakdown of GHB, raising the risk of adverse effects. However, given its widespread use among HIV-positive people, many of whom do not experience problems, further research is required to establish the risk of taking GHB alongside protease inhibitors^[2].