Gabapentin

Naomi Carr
Author: Naomi Carr Medical Reviewer: Morgan Blair Last updated:

Gabapentin, also known as Gralise and Neurontin, is an anticonvulsant medication typically used in the treatment of epilepsy, along with various other physical and mental health treatments. Always use this medication exactly as prescribed and consult with your doctor prior to starting any other medications (prescribed or over the counter) while taking gabapentin, as adverse effects can occur.

Gabapentin brand names

  • Gralise
  • Neurontin
  • Horizant

What is gabapentin prescribed for?

Gabapentin is approved by the US Food & Drug Administration (FDA) for use in the treatment of epileptic seizures, restless leg syndrome, and postherpetic neuralgia (a complication of shingles) [1].

Gabapentin can also be prescribed off-label, for uses that are not approved by the FDA, including in the treatment of bipolar disorder, anxiety disorders, treatment resistant depression, alcohol withdrawal, insomnia, posttraumatic stress disorder (PTSD), neuropathic pain, fibromyalgia, and migraines [2].

Anticonvulsant medications were initially developed for the treatment of epilepsy. Over time, research has found that these medications can be useful in managing several different conditions and symptoms, with increasing evidence for their use in psychiatric treatments [3].

How does gabapentin work?

The exact way that gabapentin works is not currently entirely understood, as there are likely various things happening in the brain at once, which is why it is able to be prescribed for different conditions [4].

It appears that gabapentin causes a change in brain activity, that is likely derived from an increase in a neurotransmitter called gamma-aminobutyric acid (GABA). This medication has various effects within the brain, such as reducing brain activity and slowing certain aspects of the nervous system, which produces several effects, including a reduction in pain, seizures, and anxiety symptoms [3][5].

How is gabapentin usually taken?

Gabapentin is available as capsules, oral solution, immediate-release tablets, and extended-release tablets. The tablets and capsules are available in a variety of strengths, from 100mg to 800mg.

Capsules must be swallowed whole without breaking. Tablets can be broken in half using the score-line, if specified in your prescription, with the remaining half to be used at the next dosage time. The oral solution must be administered with a proper measuring device, which should be provided by your doctor.

Extended-release tablets typically require fewer doses, usually just one per day, as the medication is released in the body slowly over a longer period of time, while immediate-release tablets are typically taken around three times per day.

Ensure you are clear which form of the medication you are prescribed and that you take each dose exactly as prescribed by your doctor.

Your dosage will depend on your condition, age, weight, and response to the medication. Typically, your doctor will commence your prescription on a low dose and gradually increase your dosage to find the most effective treatment for you. This may require blood tests and regular monitoring, to assess medication levels and your response to the treatment.

There are several types of gabapentin and the medication is used to treat many conditions. The type and dosage of gabapentin can vary significantly depending on the condition it is used to treat [6][7][8].

For the treatment of various physical health conditions, such as management of epileptic seizures, restless leg syndrome, and postherpetic neuralgia, a typically daily dose will be between 600-1800mg, which may be taken in 1-3 doses. Some conditions may require higher doses, up to a maximum of 4,800mg per day, which will be split into several doses.

For the treatment of various mental health conditions and other off-label uses, including bipolar disorder, PTSD, and alcohol withdrawal, you may be prescribed between 600-3600mg per day, to be taken in 1-3 doses [4].

Gabapentin may be prescribed as a mental health treatment alongside another medication, as an adjunctive treatment for your condition. Current research has not established conclusive evidence for the use of gabapentin in these treatments, so the dosage will be determined by your condition and response to the medication [3][9].

Ensure you take your medication exactly as prescribed, using the correct type of gabapentin, the correct dose, and at the correct times.

If you forget to take your medication, you can take it as soon as you remember, or if it is close to the next dosage time, skip that dose and just take the next. Never take double your prescribed dose.

How long does gabapentin stay in your system?

Depending on the type of gabapentin, the dosage, and the condition being treated, the medication will begin working within 2-8 hours, and may take several days or weeks for the full effect of your treatment to take place [3][8]. As such, it is important to continue taking this medication consistently, as prescribed.

After your last dose of gabapentin, it may take 2-3 days for the medication to entirely leave your system [2], although you may experience withdrawal symptoms for several days if you have been on high doses, for a prolonged period [10].

Do not stop taking gabapentin suddenly, as this can cause severe health issues and withdrawal symptoms [1][10]. If it is taken to treat seizures, a sudden stop in medication can cause severe seizures to occur [6]. If your doctor determines that it is safe for you to stop taking this medication, they will gradually reduce your dose, to prevent adverse effects.

Gabapentin side effects

When you start taking a new medication, you may experience some common side effects. These will likely reduce within a short time, but if they persist or become problematic, consult with your doctor, as you may need a reduced dose or a change of medication.

Common side effects of gabapentin include [1][7]:

  • Stomach upset, such as nausea, vomiting, diarrhea, or constipation
  • Dry mouth
  • Muscle or joint pain
  • Blurred vision
  • Drowsiness and fatigue
  • Headaches
  • Dizziness
  • Change in appetite and weight
  • Swelling of the feet or legs

Serious side effects of gabapentin are less common but may still occur. Contact your doctor immediately if you experience any of the following:

  • Allergic reaction, including rash, blisters, swelling of the face or mouth, fever, breathing difficulties
  • Seizures
  • Confusion
  • Memory loss
  • Severe fatigue
  • Severe stomach pain
  • Changes in your mental state, including new or worsening depression or anxiety, agitation, aggression, mania, or sleep disturbances

Gabapentin precautions

Gabapentin can cause suicidal thoughts and behaviors, particularly at the beginning of your treatment [1]. If you or your family members notice any concerning changes in your mental state, or you experience any thoughts of harming yourself, contact your doctor or mental health professional immediately.

It is important that your doctor is aware of any past or present mental health conditions you have experienced, to enable safe monitoring of your condition while on this medication, or to decide if it is safe for you.

Discuss with your doctor all your past and present physical health conditions, as they may impact your ability to take this medication safely.

You may not be able to take this medication safely if you have experienced liver or kidney disease, because of the potential side effects. If gabapentin is deemed necessary for your treatment, your doctor may wish to prescribe a lower dose and closely monitor your physical health during your treatment [2].

Inform your doctor if you are pregnant or planning to become pregnant. Current research is not clear on the safety of using gabapentin during pregnancy, so it is recommended that it is only used if the benefits of the treatment outweigh the potential risks to the fetus [6][7]. Your doctor will discuss the risks with you, so you can make an informed decision about your treatment.

Similarly, it is recommended to avoid the use of gabapentin while breastfeeding, as it may be excreted in breast milk and cause a risk of harm to your baby [6]. If it is required for treatment, it is advised to monitor your baby for any concerning changes in their physical and mental state.

Depending on your prescription and the length of time you have been on this treatment, you may experience withdrawal symptoms when coming off this medication. Your doctor will likely reduce your prescription slowly to prevent this [10].

This medication can cause drowsiness and sedation, so it is important to avoid driving until you are aware of how gabapentin affects you and it is safe to do so.

Gabapentin interactions

Gabapentin may interact with other medications, potentially increasing the risk of side effects and decreasing the effectiveness of your medication. This includes antihistamines, opiate medications, pain relief, sedatives, tranquilizers, other anticonvulsant medications, and mental health treatments, such as antidepressants, antipsychotics, and anxiolytics [1].

It is advised to avoid or limit alcohol consumption while taking gabapentin, as alcohol increases the sedating effects of the medication [7].

Always discuss your medications with your doctor prior to starting a new treatment.

Gabapentin storage

Always keep all medications out of reach of children.

Store gabapentin tablets and capsules in their original packaging, in airtight containers, and at room temperature (68°F – 77°F). Store the oral solution in a refrigerator.

If you need to dispose of medication that is out of date or no longer needed, contact a medical professional to ensure it is disposed of appropriately. Never flush medications down the toilet or put them in the trash, as this can create unnecessary risks.

What to do if you overdose on gabapentin

If you overdose on gabapentin, call a medical professional or Poison Control on 1-800-222-1222, or in case of an emergency, call 911. Symptoms of a gabapentin overdose may include blurred vision, drowsiness, dizziness, and difficulty breathing.

Frequently asked questions about gabapentin

Is gabapentin a painkiller?

Gabapentin is prescribed for several uses, including to treat nerve pain caused by injury or illness [2][11]. It should not be used as a painkiller unless prescribed by your doctor for this use.

Does gabapentin cause weight gain?

Weight gain is a potential side effect of gabapentin treatment but occurs in a small number of cases. Research suggests that when weight gain does occur during gabapentin treatment, it typically stabilizes after the initial months of treatment [7][12].

If you are concerned about your appetite and weight during your treatment, you may wish to discuss with your doctor how to maintain a healthy lifestyle and weight, to prevent unwanted weight gain.

Does gabapentin have withdrawal symptoms?

Gabapentin may cause withdrawal symptoms, particularly if used in high doses and for prolonged periods of time. Withdrawal symptoms can include agitation, confusion, stomach upset, and irregular heartbeat. If your doctor deems it necessary or safe for you to stop taking gabapentin, they will gradually reduce your prescription, to help prevent withdrawal symptoms [1][10].

Resources
  1. American Society of Health-System Pharmacists, Inc. (Revised 2020). Gabapentin. MedlinePlus. Retrieved from https://medlineplus.gov/druginfo/meds/a694007.html
  2. Yasaei, R., Katta, S., & Saadabadi, A. (2022). Gabapentin. In StatPearls [Internet]. Treasure Island, FL: StatPearls Publishing. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK493228/
  3. Berlin, R.K., Butler, P.M., & Perloff, M.D. (2015). Gabapentin Therapy in Psychiatric Disorders: A Systematic Review. The Primary Care Companion for CNS Disorders, 17(5), 10.4088/PCC.15r01821. Retrieved from https://doi.org/10.4088/PCC.15r01821
  4. Ahmed, S., Bachu, R., Kotapati, P., Adnan, M., Ahmed, R., Farooq, U., Saeed, H., Khan, A.M., Zubair, A., Qamar, I., & Begum, G. (2019) Use of Gabapentin in the Treatment of Substance Use and Psychiatric Disorders: A Systematic Review. Frontiers in Psychiatry, 10, 228. Retrieved from https://doi.org/10.3389/fpsyt.2019.00228
  5. Kiel Laboratories, Inc. (Revised 2012). Gabapentin Oral Solution. NIH. Retrieved from https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=ce4a0985-fac9-4688-9a48-0f2943bf6434&type=display
  6. Almatica Pharma, Inc. (2015). Gralise (Gabapentin) Label. FDA. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/022544s026lbl.pdf
  7. Pfizer, Inc. (Revised 2017). Neurontin(Gabapentin).FDA. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/020235s064_020882s047_021129s046lbl.pdf
  8. Patheon, Inc. (Revised 2012). Horizant (Gabapentin Enacarbil) Extended-Release Tablets.FDA. Retrieved from Pfizer, Inc. (Revised 2017). Neurontin (Gabapentin). Access Data FDA. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/022399s006,s007lbl.pdf
  9. Sokolski, K.N., Green, C., Maris, D.E., & DeMet, E.M. (1999). Gabapentin as an Adjunct to Standard Mood Stabilizers in Outpatients with Mixed Bipolar Symptomatology. Annals of Clinical Psychiatry: Official Journal of the American Academy of Clinical Psychiatrists, 11(4), 217–222. Retrieved from https://doi.org/10.1023/a:1022361412956
  10. Mah, L., & Hart, M. (2013). Gabapentin Withdrawal: Case Report in an Older Adult and Review of the Literature. Journal of the American Geriatrics Society, 61(9), 1635-1637. Retrieved from https://doi.org/10.1111/jgs.12427
  11. National Health Service. (Revised 2022). About Gapabentin. NHS. Retrieved from https://www.nhs.uk/medicines/gabapentin/about-gabapentin/
  12. DeToledo, J.C., Toledo, C., DeCerce, J., & Ramsay, R.E. (1997). Changes in Body Weight with Chronic, High-Dose Gabapentin Therapy. Therapeutic Drug Monitoring, 19(4), 394–396. Retrieved from https://doi.org/10.1097/00007691-199708000-00006
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Naomi Carr
Author Naomi Carr Writer

Naomi Carr is a writer with a background in English Literature from Oxford Brookes University.

Published: Feb 21st 2023, Last edited: Sep 22nd 2023

Morgan Blair
Medical Reviewer Morgan Blair MA, LPCC

Morgan Blair is a licensed therapist, writer and medical reviewer, holding a master’s degree in clinical mental health counseling from Northwestern University.

Content reviewed by a medical professional. Last reviewed: Feb 21st 2023