Can GHB Cause Seizures? Withdrawal and Overdose

Yes, GHB can cause seizures, and the most dangerous ones happen during withdrawal, not while high. In people who use GHB or GBL heavily and around the clock, stopping suddenly can trigger seizures within hours, because the brain has adapted to constant sedation and rebounds into dangerous over-excitation. GHB withdrawal seizures have drawn recent public attention, but they are a long-documented medical emergency. Separately, a heavy GHB overdose can produce seizure-like jerking as someone slips into unconsciousness. Both situations need emergency care. This post explains the difference, why each happens, and what to do.

Quick answers

Can GHB cause seizures? Yes. The best-documented and most dangerous are withdrawal seizures in dependent users. Acute overdose can also cause seizure-like muscle jerking (myoclonus) as a person loses consciousness.

What causes GHB withdrawal seizures? GHB constantly activates GABA-B receptors (the brain’s inhibitory “brake”). With heavy daily use the brain downregulates that braking system. Remove the GHB and there is nothing holding excitation back, so neurons fire uncontrollably. That rebound can produce seizures.

How fast do GHB withdrawal seizures start? Fast. GHB’s half-life is only 30 to 60 minutes, so withdrawal can begin within 1 to 6 hours of the last dose, and seizures are most likely in the first 24 to 48 hours.

Can you have a seizure from a GHB overdose? Seizure-like jerking and twitching (myoclonus) are common as someone goes under from a high dose. These often are not true epileptic seizures, but they look alarming and signal a dangerous overdose. Treat it as an emergency.

What do you do if someone has a GHB seizure? Do not restrain them. Clear hard objects away, cushion the head, and once jerking stops, roll them onto their side. Call emergency services, and tell paramedics GHB or GBL is involved.

Withdrawal seizures: the main danger

The seizures that kill people are withdrawal seizures. GHB works primarily as a GABA-B receptor agonist, boosting the brain’s main inhibitory (calming) system. When someone doses every few hours, day and night, for weeks, the brain compensates by downregulating that inhibitory system to stay balanced against the constant sedation.

Take the GHB away and the compensation is suddenly unopposed. The brain is left with too little inhibition and far too much excitation, a state of central nervous system hyperexcitability. Seizures are one of the most serious results. A case series of severe GHB withdrawal found that all seven patients required intensive-care admission, with seizures and delirium among the documented complications (PMID 14976275). Withdrawal that does not respond fully to standard medications is well described in the clinical literature (PMID 11574793).

Two features make this especially dangerous:

• Speed: GHB’s half-life is roughly 30 to 60 minutes, so withdrawal can start within 1 to 6 hours of the last dose. Seizures cluster in the first 24 to 48 hours.
• Who is at risk: This is a danger for daily, around-the-clock users, not occasional weekend users. The pattern that builds dependence is redosing every 2 to 4 hours to maintain effects. Losing access unexpectedly (a supplier drying up, a hospital admission for something else) can trigger withdrawal without warning.

Do not detox from heavy GHB or GBL use at home. The full picture, timeline, and why hospital treatment is required is in our GHB withdrawal guide.

Seizure-like activity during a GHB overdose

The second connection happens at the opposite end: during acute intoxication. As a large GHB dose pushes someone toward unconsciousness, myoclonic jerking, twitching, and tonic-clonic-like movements of the limbs or face are common, often appearing right around the onset of coma. In emergency department case series of acute GHB toxicity, reduced consciousness and these motor signs are frequent presentations (PMID 27581664).

An important clinical nuance: these movements often are not true epileptic seizures, and they frequently resolve on their own as the drug wears off, sometimes with the person waking abruptly. But you cannot tell the difference in the moment, and the jerking is a clear sign of a dangerous overdose, especially because GHB overdose also depresses breathing. The bystander response is the same either way: recovery position, monitor breathing, call for help.

The risk rises sharply when GHB is combined with other depressants. Mixing GHB with alcohol is one of the most lethal rave combinations, because both suppress the same systems and the overdose threshold drops. See GHB and alcohol: why this combination kills.

Why high-dose GHB engages seizure circuitry

There is a deeper pharmacological reason GHB and seizures are linked. At high doses, GHB acts on GABA-B receptors in thalamocortical circuits, the same brain networks involved in generalized absence seizures. GHB is so reliable at producing absence-type EEG activity that it is used as a laboratory model of absence seizures in animals. A critical review concluded that GHB produces events that can be confidently classified as absence seizures, though this is established mainly in the rat (PMID 25403866).

This is animal-model evidence and does not translate directly to typical human recreational doses, but it explains the mechanism: GHB is not a neutral sedative. It actively engages circuitry capable of generating seizure activity, which is part of why both extreme intoxication and withdrawal can tip into seizures.

What raises the risk

• Daily, high-frequency dosing: the single biggest risk factor for withdrawal seizures. Dependence can develop within weeks of around-the-clock use.
• Abrupt cessation: stopping cold turkey, or losing supply unexpectedly, is what triggers withdrawal seizures.
• Mixing with other depressants: alcohol, benzodiazepines, or opioids combined with GHB deepen overdose and raise the chance of seizure-like collapse.
• GBL specifically: GBL converts to GHB in the body and causes the same dependence, but it is more concentrated by volume, so overdose is easier. See GHB vs GBL.
• A personal history of epilepsy or a low seizure threshold: raises risk in both intoxication and withdrawal.

What to do if someone has a seizure

Whether it is a withdrawal seizure or overdose-related jerking, the response is the same:

1. Call emergency services immediately. Do not wait to see if it passes.
2. Do not restrain the person and do not put anything in their mouth.
3. Clear the area of hard or sharp objects and cushion their head.
4. Time the seizure. A seizure lasting more than 5 minutes, repeated seizures, or failure to regain consciousness is a dire emergency.
5. Once the jerking stops, roll them onto their side (recovery position) to protect the airway, and monitor breathing. GHB also suppresses breathing.
6. Tell paramedics it involves GHB or GBL, and whether alcohol or other drugs were taken. This directly changes treatment, especially if withdrawal is the cause.

Many jurisdictions have Good Samaritan laws that protect people who call for help at a drug-related emergency. Call anyway.

The bottom line

GHB can and does cause seizures. The most dangerous are withdrawal seizures in dependent users, driven by GABA-B rebound and capable of starting within hours of the last dose. Heavy overdose can also produce seizure-like jerking. Neither is something to ride out at home, both are reasons to call emergency services. If you use GHB or GBL daily, do not stop abruptly without medical support.

For dosing, effects, and overdose signs, see our GHB harm reduction guide. For the full withdrawal timeline and treatment, see GHB withdrawal: symptoms, timeline, and why you need medical help. Before combining GHB with anything, check our interaction checker.

Sources: PMID 14976275 | PMID 11574793 | PMID 27581664 | PMID 25403866