Also known as

Horizant, neurontin, bud, bud lite, gaba, gabby, gabbies, lyrica, nerontin


Depressant, analgesic


Gabapentin is a prescription medicine used to treat a variety of conditions including epilepsy, neuropathic pain (pain related to problems with nerve signals) and anxiety disorders.

Some people use gabapentin recreationally and consequently there is an illicit trade in this drug, including through online pharmacies [1].

What does it look like?

Gabapentin comes as white, yellow or orange tablets/capsules. They are normally swallowed, although powder from capsules may be snorted [1].


There has been an increase in the prescribing and use of this drug over the last five years, and with a growing black market of this drug being available without prescriptions through online suppliers [2].

Why take it?

Sought after effects

  • improved sociability,
  • euphoria,
  • relaxation,
  • a sense of calm [3],
  • cannabis-like high [2].

Undesired effects

  • drowsiness,
  • sedation,
  • respiratory depression,
  • death [3],
  • vomiting,
  • nausea,
  • flatulence,
  • constipation or diarrhoea,
  • poor muscle control,
  • visual disturbances [2].

How long do its effects last?

Onset of effects

  • 30 - 90 minutes [4].
  • all ROA's - 30 - 90 minutes [5].

Duration of effects

  • 5 - 8 hours [4].
  • all ROA's - 5 - 8 hours [5].



Gabapentin modulates the action of glutamate decarboxylase (GAD) and branched chain aminotransferase (BCAT), two enzymes involved in GABA biosynthesis. In human and rat studies, gabapentin was found to increase GABA biosynthesis, and to increase non-synaptic GABA neurotransmission in vitro [6]. As the GABA system is the most prolific inhibitory receptor set within the brain, its modulation results in the sedating (or calming effects) of gabapentin on the nervous system.

Gabapentin has also been shown to bind to the α2δ-1 subunit of voltage-gated calcium ion channels which contributes to its analgesic effects. It is uncertain how this contributes to gabapentin's psychoactive effects [4].


The bioavailability of gabapentin is relatively low and is inversely proportional to the dose. This means that higher doses have lower biovailability than lower doses. The bioavailability of gabapentin is approximately 60%, 47%, 34%, 33%, and 27% following 900, 1200, 2400, 3600, and 4800 mg/day [4].


Five to seven hours [7].

Lethal dosage

People who accidentally or intentionally overdose may experience drowsiness, sedation, blurred vision, slurred speech, somnolence and possibly death (if a very high amount was taken and particularly if combined with alcohol). Serum gabapentin concentrations may be measured to confirm diagnosis [8], [4].

A lethal dose of gabapentin was not identified in mice and rats receiving single oral doses as high as 8000 mg/kg. Signs of acute toxicity in animals included ataxia, laboured breathing, ptosis, sedation, hypoactivity, or excitation.

Acute oral overdoses of neurontin up to 49 grams have been reported. In these cases, double vision, slurred speech, drowsiness, lethargy and diarrhoea, were observed. All patients recovered with supportive care [9].


Gabapentin has a low toxicity relative to dose [4]. Gabapentin should be used carefully in patients with renal impairment due to possible accumulation and toxicity [9].


Gabapentin is not considered psychologically addictive. However, it is possible to develop a physical dependence on the drug. In fact, people can experience withdrawal symptoms for up to 45 days after they stop taking gabapentin. Although gabapentin does give some people a euphoric 'high' which can cause abuse, gabapentin abusers do not present with the kind of compulsive, drug-seeking behaviour or strong cravings associated with other more common depressants such as opioids, alcohol or benzodiazepines.

Tolerance will develop to the anxiolytic effects with prolonged continous usage. After cessation, the tolerance returns to baseline in 7 - 14 days. Withdrawal symptoms or rebound symptoms may occur after ceasing usage abruptly following a few weeks or longer of steady dosing, and may necessitate a gradual dose reduction [4].

Mode of use

Gabapentin capsules and tablets are normally swallowed, but there have been reports of the powder from gabapentin capsules being snorted [10].


  • dizziness,
  • drowsiness,
  • dry mouth,
  • blurred vision,
  • headache,
  • diarrhoea,
  • oedema [11].
  • constipation,
  • nausea,
  • vomiting,
  • tremors,
  • flatulence,
  • increases in blood pressure,
  • trouble sleeping,
  • weight gain,
  • feelings of depression, hostility and anxiety [10].


  • hallucinations,
  • suicidal thoughts,
  • jaundice [10].

Physical effects

  • muscle relaxation,
  • physical euphoria,
  • pain relief,
  • perception of decreased weight,
  • sedation,
  • seizure suppression,
  • dizziness [4].

Cognitive effects

  • cognitive euphoria,
  • depersonalisation,
  • derealisation,
  • dream potentiation,
  • amnesia,
  • anxiety suppression,
  • decreased libido,
  • emotion suppression,
  • thought deceleration [4].

Visual effects

  • visual disconnection,
  • internal hallucinations [4].


  • swollen hands and feet,
  • headaches,
  • abnormal thoughts,
  • suicidal thoughts,
  • shortness of breath,
  • chest pain,
  • mouth sores,
  • chills,
  • nausea,
  • coughing,
  • tremor,
  • cold symptoms [2],
  • drowsiness,
  • weakness,
  • dizziness,
  • shaking in one part of the body,
  • blurry or doubled vision,
  • unsteadiness,
  • anxiety,
  • difficulty with memory,
  • uncontrolled eye movement,
  • vomiting,
  • heartburn,
  • diarrhoea,
  • dry mouth,
  • constipation,
  • increased appetite,
  • weight gain,
  • back or joint pain,
  • fever,
  • ear pain,
  • red, itchy eyes [7].


  • double vision,
  • slurred speech,
  • drowsiness,
  • diarrhoea [7].

Allergic reaction

  • increased seizures,
  • fever,
  • swollen glands,
  • body aches,
  • flu-like symptoms,
  • skin rash,
  • easy bruising or bleeding,
  • severe tingling, numbness, pain, or muscle weakness,
  • upper stomach pain,
  • loss of appetite,
  • dark urine,
  • jaundice,
  • chest pain,
  • irregular heart rhythm,
  • short of breath,
  • confusion,
  • nausea and vomiting,
  • swelling,
  • rapid weight gain,
  • change in urination,
  • new or worsening cough,
  • fever,
  • trouble breathing,
  • rapid back and forth movement of your eyes,
  • severe skin reaction [11].


  • dizziness,
  • forgetfulness,
  • drowsiness,
  • confusion [10].


  • drowsiness,
  • unsteadiness,
  • loss of coordination,
  • clumsiness,
  • vision disturbances [2].


  • insomnia,
  • weight gain,
  • dependence,
  • hallucinations,
  • heart problems - including heart failure,
  • depression,
  • agitation
  • panic attacks [2].


It's likely that most of the gabapentin that is available on the black market has been either stolen from a hospital or pharmacy or stolen (possibly bought) from people who have been prescribed gabapentin. They might have also been imported from abroad.

You cannot normally be sure of the purity unless you are certain that the drug you have is a genuine pharmacy medicine [10].


Can you get addicted

It is recommended that prescribed gabapentin use is not stopped abruptly as it may cause anxiety, insomnia, nausea, pain and sweating [10].

Dangerous interactions

Gabapentin significantly potentates the effects of alcohol, benzodiazepines and other GABAgenics which may lead to blackouts [4].


Symptoms of withdrawal typically begin within 12 hours of the last drug use and may last up to a week [7].

  • anxiety,
  • disturbed sleep,
  • nausea,
  • pain,
  • sweating [10],
  • insomnia,
  • headache,
  • diarrhoea [2].

Harm Reduction

  • do not take the drug in higher doses, more frequent doses, or for longer than you were prescribed to do so by a doctor,
  • do not stop taking gabapentin suddenly. Unless you are experiencing extreme side-effects caused by the drug, you must talk to your doctor before you stop taking it. Stopping the medication suddenly can lead to 'withdrawal symptoms such as anxiety, difficulty falling asleep or staying asleep, nausea, pain, and sweating',
  • let your doctor know if you have any history of drug abuse before you start your gabapentin regimen. If you are taking the drug as part of a treatment program for addiction, make sure you attend therapy sessions and discuss your treatment needs with your doctor on a regular basis [12].


Gabapentin is a prescription only medicines and can only be prescribed following a consultation with a doctor.

In January 2016, the ACMD recommended that gabapentin should be controlled under the Misuse of Drugs Act 1971 as Class C substances [1].

Did you know?

Like drinking and driving, driving while under the influence of drugs is illegal - with some drugs you can still be unfit to drive the day after using. You can get a heavy fine, be disqualified from driving or even go to prison [10].


If the drug is snorted/sniffed - a razor blade will be used to chop it into lines on a hard level surface such as a mirror or a sheet of glass or a tile [2].


  1. 1.0 1.1 1.2 Gabapentin, 2017,
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Gabapentin, 2015,
  3. 3.0 3.1 Advice for prescribers on the risk of the misuse of pregabalin and gabapentin, 2014,
  4. 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 Gabapentin, 2017,
  5. 5.0 5.1 5.2 Gabapentin, 2017,
  6. Taylor, C. P., Mechanisms of action of gabapentin, Revue Neurologique (Paris), 1997, S39-S45,
  7. 7.0 7.1 7.2 7.3 Gabapentin: Withdrawal Symptoms, Abuse & Use in Drug & Alcohol Detox, 2017,
  8. Baselt, R. C., Disposition of Toxic Drugs and Chemicals in Man, 2008, 8th edition, Biomedical Publications, Foster City, CA, ISBN: 978-0-9626523-7-0, 677-678
  9. 9.0 9.1 Highlights Of Prescribing Information, Pfizer, 2014,
  10. 10.0 10.1 10.2 10.3 10.4 10.5 10.6 10.7 Gabapentin, 2015,
  11. 11.0 11.1 Horizant: Reviews, Side Effects, Uses, Dosage and Directions, 2017,
  12. Gabapentin abuse, 2016,