Gabapentin

Medically Reviewed By University of Illinois Chicago Drug Information Group Alyssa Peckham, PharmD, BCPP
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Gabapentin at a glance

Key highlights to know about gabapentin are:

  • Gabapentin is approved by the Food and Drug Administration (FDA) to treat partial seizure and postherpetic neuralgia (a type of pain that occurs following shingles, a painful rash caused by a herpes zoster infection).
  • Gabapentin is taken by mouth with or without food.
  • Gabapentin should not be used with alcohol.
  • Gabapentin tablets, capsules, and oral solution are available as a generic medication. Gabapentin has several brand names, including Neurontin, Gralise, and Horizant. These brand name products cannot be substituted with one another. This page may not include all important information about Gralise and Horizant, as they are used to treat conditions that differ from other forms of gabapentin.
  • Gabapentin is typically a moderate-cost drug, defined as costing $30–$100 per month.

Important safety warnings for gabapentin

People taking gabapentin should be aware of these safety warnings:

  • Suicidal thoughts warning: Gabapentin can cause suicidal thoughts or actions. This is a rare side effect that happens in 1 in 500 people. Tell your doctor right away if you notice new or sudden changes in mood, behavior, actions, thoughts, or feelings.
  • Changes in behavior warning: Gabapentin can cause changes in behavior or thoughts for children 3–12 years of age. Talk with your doctor right away if your child has emotional changes, aggressive actions, issues concentrating, changes in school performance, or hyperactivity.
  • Allergic reaction warning: This drug may cause a serious allergic reaction. Allergic reactions usually happen after one of your first doses, but they sometimes do not occur until you have been taking a medication for months. Talk with your doctor about these warnings in the context of your individual treatment plan and medical history.
  • Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) warning: Gabapentin can cause a rare type of reaction called DRESS. Signs of DRESS include rash, fever, or swelling. Contact your doctor immediately, if you experience these symptoms.
  • Serious breathing problems warning: Serious breathing problems can occur when taking gabapentin. They are more common if you have a condition that causes breathing problems. Taking gabapentin with other drugs that increase sleepiness can also increase the chance of having breathing problems. If you experience breathing problems, get immediate help.
  • Sleepiness and dizziness warning: Gabapentin commonly causes sleepiness, tiredness, and dizziness. Using gabapentin with other drugs that cause sleepiness can worsen this side effect. Talk with your doctor if you are experiencing sleepiness or dizziness or if you are starting new medications with your gabapentin.
  • Effect on driving and using heavy machinery warning: Gabapentin may affect your ability to drive. When starting gabapentin, avoid driving until you know how the drug affects you. Likewise, gabapentin can cause sleepiness. Use of heavy machinery should be avoided until you know if the drug makes you tired.

What gabapentin treats

This medication is FDA approved to treat:

  • Pain due to damaged nerves following shingles in adults. Shingles is a painful rash caused by a herpes zoster infection. Pain following shingles is sometimes called postherpetic neuralgia.
  • Partial seizures when used with other seizure medications in adults and children older than 3 years of age.

Gabapentin is commonly used for conditions such as anxiety, alcohol use disorder, and restless legs syndrome. Healthcare professionals sometimes prescribe medications for different uses. Ask your doctor or pharmacist for information about other uses of this medication.

How it works

At this time, it is not exactly known how gabapentin works. Gabapentin is similar to gamma-aminobutyric acid, a chemical in the brain known as GABA. Gabapentin treats seizures by decreasing excitement in the brain. For postherpetic pain, gabapentin changes the way that the body feels pain.

Gabapentin should be taken by mouth. It is available as a generic and brand name medication. The brand name of gabapentin is Neurontin. However, healthcare professionals typically prescribe the generic form of the drug.

Gabapentin is available as an extended-release tablet and a film-coated tablet. These forms are not equivalent to other forms of gabapentin (they cannot be substituted for one another). They are available as brand name products, named Horizant (extended-release tablet) and Gralise (film-coated tablet). They are not used to treat seizures, like other forms of gabapentin. Horizant may be used to treat conditions that differ from those treated by other forms of gabapentin.

Side effects of gabapentin

Gabapentin side effects are possible and may go away with continued use. Serious side effects are rare. Gabapentin should be started at a low dose and increased over several days. This may help to decrease side effects.

Common side effects

The more common side effects that occur with gabapentin include:

  • feeling drowsy or tired
  • lack of coordination
  • nausea and vomiting
  • difficulty speaking
  • double vision
  • unusual eye movement
  • tremor
  • viral infection or fever
  • jerky movements
  • swelling in the legs and feet

Serious side effects

Call your doctor right away if you have serious side effects. Seek emergency care (call 911) if you experience life threatening symptoms, such as difficulty breathing; chest pain; loss of consciousness; sudden vision changes; or swelling of the face, mouth, tongue, or throat.

Serious side effects and their symptoms can include the following:

  • Suicidal thoughts. Signs and symptoms can include:
    • new or sudden changes in mood, behavior, thoughts, feelings, or actions
    • new or worsening depression, anxiety, or panic attacks
    • agitation, restlessness, anger, or irritability
    • thoughts about suicide or dying
  • Changes in behavior (most common in children). Symptoms can include:
    • emotional changes
    • aggressive actions
    • issues concentrating
    • changes in school performance
    • hyperactivity
  • Allergic reactions. Symptoms can include:
  • Serious breathing problems. Symptoms can include:
    • severe sleepiness
    • decreased awareness
    • decreased breathing

Other side effects are possible. Talk with your doctor or pharmacist if you have any side effect that bothers you or that does not go away.

Costs of gabapentin

Without insurance, gabapentin is typically a moderate-cost drug (defined as costing $30–$100 per month). You can check the out-of-pocket cash pay price for gabapentin on prescription drug discount websites.

With insurance, prices can vary considerably. Insurance may control whether a brand or a generic version is used. Individual health plans may have preferred drugs with better pricing. If the price of gabapentin on your health plan is too expensive, ask your healthcare professional or pharmacist if there is an equivalent drug you can substitute.

How gabapentin may interact with other medicines

Gabapentin may interact with other prescription and over-the-counter medications, vitamins, or herbal supplements you may be taking. To help avoid harmful interactions, your doctor should manage all of your medications carefully. Be sure to tell your doctor about all medications, vitamins, or herbal supplements you are taking. To find out how this drug might interact with something else you are taking, talk with your doctor or pharmacist.

This is not a complete list of drugs that may interact with gabapentin. However, examples of drugs that may interact with gabapentin include:

Opioids

Taking gabapentin with opioid pain medications can cause sleepiness and breathing problems. This can lead to death. When gabapentin is started with opioids, a lower dose may be used. Examples of opioid pain medications include:

  • Fentanyl (Duragesic, Actiq, Subsys, Lazanda, Fentora, Ionsys)
  • Methadone (Dolophine, Methadose)
  • Morphine (MS Contin)
  • Hydrocodone (Hysingla ER, Zohydro ER) and drugs that contain hydrocodone (Norco, Lortab, Vicodin, Vicoprofen)
  • Oxycodone (Oxycontin, Roxicodone, Oxaydo) and drugs that contain oxycodone (Endocet, Percocet)
  • Buprenorphine (Belbuca, Buprenex, Butrans, Sublocade)

Antacids containing aluminum and magnesium

Taking gabapentin with antacids containing magnesium and aluminum can cause gabapentin to not work as well. Gabapentin should be taken at least two hours after antacids. Examples of antacids that contain aluminum and magnesium include:

  • Maalox
  • Mylanta
  • Gelusil
  • Gaviscon
  • Di-Gel

Disclaimer: Since drugs interact differently in each person, this information is not guaranteed to include all possible interactions. This information is not a substitute for medical advice. Always speak with your healthcare professional about possible interactions with all prescription drugs, vitamins, herbal supplements, and over-the-counter drugs that you are taking.

Other gabapentin alerts

This drug comes with several alerts and warnings:

Kidney problems

  • If you have kidney problems, are on dialysis, or have lower kidney function, you will receive a lower dose of gabapentin.

Elderly age

  • Kidney function usually goes down with older age. Your healthcare professional should prescribe you a lower dose of gabapentin if you have low kidney function.  

Call your doctor right away if you have serious side effects. Seek emergency care (call 911) if you experience life threatening symptoms, such as difficulty breathing, chest pain, loss of consciousness, sudden vision changes, or swelling of the face, mouth, tongue, or throat.

For pregnant and breastfeeding people

There are no known issues with taking gabapentin for people who are pregnant or breastfeeding. If you are concerned about taking gabapentin while pregnant or breastfeeding, talk with your healthcare professional.

Can I take gabapentin when pregnant?

It is unknown whether taking gabapentin while pregnant will harm your unborn baby.

Tell your doctor if you are pregnant or plan to become pregnant and are taking gabapentin. A pregnancy exposure registry exists for people who take this drug — and other drugs for seizures — during pregnancy in order to collect information about the health of you and your baby. To enroll yourself or get more information call 1-888-233-2334.

Can I take gabapentin when breastfeeding?

Gabapentin passes into breast milk. The effect that this will have on your child is unknown. Talk with a healthcare professional about the risks and benefits of breastfeeding while taking gabapentin. They will work with you to decide on a plan for feeding your baby.

How and when to take gabapentin

This drug is taken by mouth with water. Gabapentin can be taken with or without food, at the times prescribed by your doctor. If your doctor tells you to take half of a tablet, use the other half of the tablet for your next dose. Tablets that have been cut in half should be used within 28 days. Throw away any unused half-tablets after 28 days.

All possible dosages and forms may not be included here. Your dose will depend on:

  • age
  • condition being treated
  • severity of your condition
  • other medical conditions you have

Drug forms and strengths

  • Capsule:
    • 100 milligrams (mg)
    • 300 mg
    • 400 mg
  • Tablet:
    • 600 mg
    • 800 mg
  • Oral solution:
    • 250 mg per 5 milliliters (ml)

Dosage for pain following a shingles infection (postherpetic pain)

  • Adults (age ≥ 18 years):
    • Day 1: one time dose of 300 mg
    • Day 2: 300 mg two times a day
    • Day 3: 300 mg three times a day
    • Maximum dose: 600 mg three times a day

Dosage for epilepsy with partial seizures

  • Children (age 3 to 11 years)
    • Doses are based on weight and given three times per day.
    • Doses may be increased over the first three days to the goal dose.
  • Adolescents and adults (age ≥ 12 years)
    • Starting dose: 300 mg three times a day
    • Typical dose: 300 to 600 mg three times a day
    • Doses as high as 1200 mg three times a day have been used.

Patients with kidney problems should receive a lower dose.

If you miss a dose of gabapentin

If you forget to take a dose, take the missed dose as soon as you remember. If it is almost time for your next dose, skip the missed dose and take the dose at the regular time. Do not take two doses at the same time.

If you take too much gabapentin

If you take too much gabapentin, you are at a higher risk of having overdose symptoms. Symptoms of overdose include:

Overdose can also cause problems with breathing that can lead to death. If you think you have taken too much of this medication, call your doctor or local poison control center at 1-800-222-1222.
Seek emergency care (call 911) if you experience life threatening symptoms, such as:

  • difficulty breathing
  • chest pain
  • loss of consciousness
  • sudden vision changes
  • swelling of the face, mouth, tongue, or throat

Helpful tips when taking gabapentin

Keep these considerations in mind if your healthcare professional prescribes gabapentin for you.

General

  • Gabapentin may be taken with or without food.
  • Take gabapentin with water.
  • If you are told to take half of a tablet, store the other half in the original bottle. Use this half tablet for your next dose. If you do not use a half tablet within 28 days of cutting it, throw it away.
  • Do not use alcohol if you are taking gabapentin. This may cause abnormal sleepiness or confusion.

Storage

  • Store gabapentin tablets at room temperature, 77°F (25°C). Occasionally, gabapentin can be stored from 59°F to 86°F (15°C to 30°C).
  • Gabapentin oral solution should be refrigerated, 36°F to 46°F (2°C to 8°C).

Alcohol

Alcohol should not be consumed while taking gabapentin. This may cause worse sleepiness or confusion. Talk with your doctor before consuming alcohol with gabapentin.

Refills

Your doctor will write the number of authorized refills on your prescription. Talk with your pharmacist if you have questions about refills.

Travel

When planning to travel, keep these tips in mind for packing your medication:

  • Bring enough medication for the full number of days of your trip, plus at least two days to be safe.
  • Keep medication with you, in a purse or a carry-on bag if flying. Do not put it into a checked bag in case you are separated from your luggage.
  • Keep your medications in their original containers, if possible, to reduce delays during airport or security screening. Keep all your medications together to expedite the process.
  • Avoid leaving your medication in a parked car for extended periods to protect it from extreme temperatures (hot or cold).

When traveling with gabapentin oral solution:

  • Pack your medication in an insulated travel cooler with an ice pack and extra Ziploc bags for ice.
  • For longer trips, use the Ziploc bags for ice once the ice pack is no longer solid.
  • Liquid medications, associated supplies, and ice packs are allowed through security when flying. They are also exempt from the 3-1-1 liquid rule.

Availability

Many pharmacies stock this drug. When filling your prescription, be sure to call ahead to make sure your pharmacy carries it and has it in stock.

Prior authorization

Many insurance companies do not require prior authorization for this drug. If prior authorization is needed, your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Medications similar to gabapentin

Gabapentin is used for treating postherpetic pain and partial seizures. There are several other medications approved for both of these conditions. None work exactly like gabapentin. Lyrica (pregabalin) works in a similar way as gabapentin, but it treats different conditions. Each medication has its own benefits and side effects profile.

Discontinuing use of gabapentin

When gabapentin is discontinued, the dose should be reduced gradually over at least seven days. Anxiety, trouble sleeping, nausea, pain, and sweating can occur if gabapentin is suddenly stopped. You may also experience an increase in seizures, although the risk of increased seizures mainly affects people with preexisting seizure disorders. Do not stop taking this drug unless instructed by your doctor.

Healthgrades disclaimer:

This information is for educational purposes only. It should not be interpreted as medical advice, diagnosis, or treatment. Healthgrades takes every effort to ensure this information is accurate and up to date. This content is not intended to cover all possible uses, side effects, warnings, precautions, allergic reactions, or drug interactions. Do not assume that the absence of such information means the medication is safe for your personal use. Always consult your doctor, pharmacist, or healthcare professional before taking or discontinuing any medication.

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Medical Reviewers: University of Illinois Chicago Drug Information Group Alyssa Peckham, PharmD, BCPP
Last Review Date: 2021 Jul 12
THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Neurontin - gabapentin capsule; Neurontin - gabapentin tablet, film coated; Neurontin - gabapentin solution. (2021). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=ee9ad9ed-6d9f-4ee1-9d7f-cfad438df388
  2. Gabapentin. (2020). https://medlineplus.gov/druginfo/meds/a694007.html