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Gabapentin: Top 9 Facts You Need to Know

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Jan 15, 2021.

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Gabapentin: A Versatile Medication

Gabapentin is a epilepsy medication in the class of drugs known as anticonvulsants, but it is so much more than that.

  • Common brands names include Gralise, Horizant, and Neurontin.
  • Gabapentin is one of the most common drugs in the US as it has so many uses, and in 2020 it remained ranked in the top 20 list of most prescribed drugs.

Gabapentin affects chemicals and nerves in the body that are involved in the cause of seizures and in some types of nerve pain.

Gabapentin was first approved in 1993 and is often used for these medical conditions:

Gabapentin Use for Seizures

If you are familiar with Neurontin (gabapentin), you remember it was first approved by the FDA for patients with seizures.

  • Gabapentin is used to treat seizures in adults and children who are at least 3 years old. It also comes in a liquid dose form for small children who have trouble swallowing capsules.
  • You can take gabapentin with or without food. But wait at least two hours after taking an antacid that contains magnesium, calcium or aluminum before taking your gabapentin dose. This drug interaction between the antacid and gabapentin may prevent proper absorption of the anti-seizure medication and lower its effectiveness.
  • You should avoid or limit the use of alcohol (ethanol) while being treated with gabapentin.
  • If you take gabapentin three times a day for seizures, do not allow more than 12 hours to pass between any two gabapentin doses.

The U.S. Centers for Disease Control and Prevention (CDC) reports that record numbers of Americans are living with epilepsy. Reasons for the increased numbers include population growth, better diagnosis, and longer life span.

What is Postherpetic Neuralgia?

Most people are familiar with the seizures that occur with epilepsy, but what is postherpetic neuralgia (PHN)?

Postherpetic neuralgia can occur due to an outbreak of shingles. Shingles, also known as herpes zoster, occurs when a chicken pox virus deep-seated in your nerve activates again later in life and causes a skin rash.

  • Most cases of shingles clear up within a few weeks, and your doctor might give you an antiviral medication to help.
  • However, postherpetic neuralgia is a burning pain that lasts for more than a month after the rash and blisters have cleared up. In fact, the burning pain that affects the nerves may last for months or even years.
  • Not everyone gets postherpetic neuralgia from shingles, only about 10% to 15% of people, according to the CDC.

The risk of postherpetic neuralgia increases with age, primarily affecting people older than 60 years of age. You may be more at risk for the lingering pain of PHN if the shingles breaks out on your face, too.

What is Restless Legs Syndrome?

Restless legs syndrome (RLS) results in an uncontrollable urge to move your legs around, usually due to leg discomfort.

The symptoms typically occur in the evenings or at night while you're sitting, lying down, or trying to sleep. Moving around eases the leg discomfort, but only temporarily.

Restless legs syndrome generally worsens as you age, but it can happen at any age. It can disrupt sleep - leading to daytime drowsiness -- and make traveling, like air travel or long car rides -- difficult.

Experts still do not know the cause of restless legs syndrome. Some evidence suggests that there is a problem related to a brain chemical or neurotransmitter called dopamine.

How Gabapentin Comes: The Immediate-Release Form

Gabapentin comes in many different forms and doses at the pharmacy. Use only the brand and form of gabapentin prescribed by your doctor. It is wise to check your medicine at the pharmacy each time you get a refill to be sure you have the correct form.

  • Gabapentin immediate-release (IR) comes in capsules (100, 300, 400 mg), tablets (600, and 800 mg) and as a liquid oral solution (250 mg per 5 mL).
  • Doses of the IR form are usually given three times per day for seizures and postherpetic neuralgia. The IR form of gabapentin (Neurontin) is also available generically. These generic options are very inexpensive, especially if you are using an online coupon.
  • Ask your doctor or pharmacist if you are able to use the generic immediate-release form of gabapentin for your condition (this may not always be possible), but it could save you hundreds of dollars each month or might even be cheaper than your insurance copay.
  • But remember, prices can fluctuate wildly, so check with other pharmacies if the price seems out of reach. Be sure to check for online coupons, too, that can save you money on both generics and brands.

Extended-Release (ER) Forms: What's the Difference?

  • Gralise (gabapentin) comes as a 300 and 600 milligram (mg) extended-release (ER) tablet and in a convenience dose start pack of 78 tablets.
  • Horizant (gabapentin enacarbil) is available in a 300 and 600 mg ER tablet.

These products are not interchangeable with other formulations of gabapentin, and no generics exist yet. The safety and effectiveness of Gralise or Horizant in patients with epilepsy has not been studied.

Because they are longer-acting, the total dose is given only once or twice daily, which can be more convenient and improve your ability to stick with the correct dosing. Doses are usually increased gradually to help prevent side effects.

Gralise should be taken with the evening meal. Horizant should also be taken with food. Because these products are extended-release, it is important not to chew, crush, split or try to dissolve the pills.

  • Gralise, as a brand, is FDA-approved only to treat post-herpetic neuralgia.
  • Horizant is used for restless leg syndrome and post-herpetic neuralgia in adults. Horizant is not recommended for patients who are required to sleep during the daytime and remain awake at night.
  • No generics exist yet for these brands. Generic Gralise may not be available until 2024, and a generic for Horizant may not be on shleves until 2025 or 2026.

It is important you use only the brand or the generic form of gabapentin that your doctor has prescribed. Check your medicine each time you get a refill at the pharmacy; be sure you have received the correct brand.

When your doctor determines that you should stop or change this medication, it should be slowly discontinued over at least one week. Patients with kidney disease may need to have their doses adjusted.

Off-Label Uses of Gabapentin

Unapproved, or "off-label" uses of gabapentin are uses that have not been approved by the FDA and are not found in the package labeling. However, some doctors may have had good experience using gabapentin in an off-label fashion, and it may be an accepted use even though not specifically listed in the label.

For example, gabapentin has been used off-label in the treatment of:

However, the FDA turned down the approval for menopausal hot flashes due to lack of effectiveness and side effects like dizziness, fatigue and balance problems.

A study published in JAMA Surgery noted that gabapentin has been used in surgical patients to help reduce the amount of opioid painkillers required for pain. When patients received gabapentin before and after surgery, the need for continued opioid painkillers was reduced by 24%, according to researchers at Stanford University School of Medicine.

And research published in the Canadian Medical Association Journal has shown limited use for several anticonvulsants in the treatment of lower back pain, including gabapentin, pregabalin or topiramate.

Only use a drug for an off-label use if your doctor has specifically written you a prescription with appropriate dosing.

Gabapentin Side Effects and Abuse Potential

Gabapentin is usually well-tolerated but there may be side effects that occur more commonly, especially at the beginning of treatment.

Common side effects of gabapentinoids like gabapentin include:

  • drowsiness, dizziness, blurry or double vision
  • difficulty with coordination and concentration
  • swelling of the hands, legs, and feet
  • depression and suicide tendencies
  • serious allergic reactions
  • weight gain

Avoid or limit the use of alcohol (in beverages or medicines) with gabapentin as it can worsen drowsiness.

In an alarming report, it was noted that 1 in 5 opioid (narcotic) medication users may also be misusing and abusing gabapentin. Gabapentin can be abused to boost the high a person gets from opioid painkillers like oxycodone, muscle relaxants like Soma, and anxiety medications, such as Valium and Xanax.

In 2019, the FDA issued an alert that serious breathing problems have been reported with gabapentin and other related drugs, like Lyrica (pregabalin) in people at risk of slowed breathing. This includes:

  • people who use opioid pain medicines and other drugs that depress the central nervous system. CNS depressants include opioids, anti-anxiety medicines, antidepressants, and antihistamines.
  • people with chronic obstructive pulmonary disease (COPD) that reduce lung function
  • the elderly

These serious breathing problems may be fatal. Read more about this serious FDA warning here.

Don't Abruptly Stop Gabapentin

Thinking of stopping your gabapentin? Think again, and contact your doctor first.

Abruptly stopping any form of gabapentin can lead to worsened seizures and unpleasant withdrawal side effects, so it's best to slowly stop the drug over a period of time. Your doctor will direct you on how to do this appropriately. Doses may need to be reduced with kidney disease, too.

Bottom line?

  • It's important to review the medication guide that comes with your gabapentin prescription, whether it be the generic, or the brand Neurontin, Horizant or Gralise.
  • There are many side effects, and most you will not experience; however, it's still important to be aware of them and discuss with your doctor.

To learn more about gabapentin, join the gabapentin Support Group and Q&A Section. Ask questions, stay on top of the news, and contribute your experiences to patients just like you.

Finished: Gabapentin: Top 9 Facts You Need to Know

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  • Medical Expenditure Panel Survey (MEPS) 2007-2017. Agency for Healthcare Research and Quality (AHRQ), Rockville, MD. ClinCalc DrugStats Database version 20.0. Accessed Jan. 15, 2021 at
  • FDA Warns About Serious Breathing Problems with Seizure and Nerve Pain Medicines Gabapentin (Neurontin, Gralise, Horizant) and Pregabalin (Lyrica, Lyrica CR) in Patients with Respiratory Risk Factors. Accessed Jan. 15, 2021 at
  • Anti-seizure Meds Won't Ease Low Back Pain. July 6, 2018. Accessed Jan. 23, 2020.
  • CDC. Shingles Surveillance. Accessed Jan. 15, 2021 at
  • 1 in 5 Opioid Users Also Might Be Abusing Seizure Drug: Study. Accessed Jan. 23, 2020.
  • Gabapentin product information. Accessed Jan. 23, 2020
  • Gabapentin: Patient drug information. Up To Date (Lexicomp). Accessed Jan. 23, 2020.
  • Gabapentin May Help Surgical Patients Stop Opioids Sooner. Accessed Jan. 23, 2020.
  • Number of Americans With Epilepsy at Record Level. Accessed Jan. 23, 2020.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.