GHB and GBL (liquid ecstasy, G, Gina)
GHB and GBL are central nervous system depressants that act on GABA receptors. The margin between a recreational dose and an overdose is very narrow, especially when combined with alcohol, other depressants, or antiretrovirals that can increase their effects.
What are they?
GHB (gamma-hydroxybutyric acid) and GBL (gamma-butyrolactone) are central nervous system depressants. GBL is a prodrug: it is rapidly converted into GHB in the body once used.
They are often used in chemsex settings because of their disinhibiting and relaxing effects. The margin between a recreational dose and a dose that causes loss of consciousness is very narrow, which makes them especially dangerous.
GBL adds another risk: it is very hard to measure the exact dose, which increases overdose risk considerably.
How are they used?
- Liquid dissolved in drinks (most common)
- Taken directly in very small amounts (with a dosing tool)
- In vials or small bottles
- Mixed into drinks (which makes the dose harder to identify)
Basic precautions:
- Always use a dosing tool (pipette or needle-free syringe) to measure the exact amount
- Never mix it into the same drink as alcohol
- Always label the bottle to avoid mistakes
How do they work?
GHB and GBL work by increasing GABA activity (the main inhibitory neurotransmitter in the central nervous system), which may produce:
- Relaxation and euphoria
- Disinhibition and increased sociability
- Drowsiness and sedation
- Loss of motor coordination
At high doses, they depress vital functions:
- Respiratory depression (slow, shallow breathing)
- Reduced heart rate
- Loss of consciousness
Effects usually start 15 to 30 minutes after use and may last 2 to 6 hours.
Interactions with antiretrovirals
Several antiretrovirals may inhibit the enzymes that metabolise GHB/GBL, increasing blood levels and strengthening their depressant effects.
They may INCREASE sedation and central nervous system depression
Higher GHB/GBL levels may cause:
- Profound drowsiness and inability to wake up
- Severe confusion
- Respiratory depression (life-threatening)
- Loss of consciousness
They may REDUCE alertness and response capacity
- Greater risk of accidents and injuries
- Inability to ask for help if consciousness is lost
Medicines requiring more caution
| Group / Medicine | Interaction risk | Notes |
|---|---|---|
| Protease inhibitors (PI): lopinavir/ritonavir, atazanavir, darunavir | High | Enzyme inhibition; may significantly raise GHB levels |
| Integrase inhibitors: elvitegravir, raltegravir, dolutegravir | High | Especially elvitegravir boosted with cobicistat |
| NNRTIs: efavirenz, nevirapine | Moderate | May alter liver metabolism of GHB/GBL |
| Maraviroc | Moderate | Interaction potential because of shared metabolism |
Harm reduction
- Use the lowest amount possible and measure with a dosing tool
- NEVER combine with alcohol, benzodiazepines, opioids, or any other CNS depressant (overdose risk rises dramatically)
- Wait at least 2 hours between doses to avoid accumulation
- Hydrate and rest in a safe place
- Do not use alone: always have a trusted person nearby who knows what you took
- Tell your healthcare team about GHB/GBL use
- Make sure your group knows the emergency signal: if someone becomes unconscious, it is an emergency
Warning signs
- Extreme drowsiness or loss of consciousness (cannot be awakened)
- Slow or shallow breathing
- Nausea or vomiting (aspiration risk if consciousness is lost)
- Cold or bluish skin, or excessive sweating
- Seizures or muscle rigidity
When should you seek medical care?
- Loss of consciousness or the person does not wake up to stimulation
- Very slow or irregular breathing
- Seizures
- Persistent vomiting (aspiration risk)
- Bluish skin (cyanosis)
In these situations, call emergency services immediately. If the person is unconscious but breathing, place them in the recovery position. Do not leave them alone under any circumstances.
What does the evidence say?
GHB has a very narrow therapeutic index: the difference between a dose that produces the desired effect and one that causes loss of consciousness or respiratory depression is small and varies between people. Combining it with protease inhibitors boosted with ritonavir or cobicistat may significantly increase plasma GHB levels. Combining it with alcohol or other CNS depressants is linked to a dramatic increase in the risk of fatal overdose. Evidence on specific interactions with integrase inhibitors is more limited, but caution is justified.