What Ingredients Are in Gabapentin?

Gabapentin is an anti-epileptic drug, also called an anticonvulsant. It affects chemicals and nerves in the body that are involved in the cause of seizures and some types of pain.

Gabapentin
Gabapentin

Some inactive ingredients in the gabapentin tablets or capsules include:

      • Lactose
      • Talc
      • Cornstarch
      • Gelatin
      • Colors such as FD&C blue no. 2, yellow iron oxide
      • Titanium dioxide
      • Poloxamer 407
      • Magnesium stearate
      • Copovidone, cornstarch
      • Candelilla wax
      • Hydroxypropyl cellulose

Dosing information

Usual Adult Dose for Epilepsy:

Initial dose: 300 mg orally on day one, 300 mg orally 2 times day on day two, then 300 mg orally 3 times a day on day three
Maintenance dose: 300 to 600 mg orally 3 times a day
Maximum dose: 3600 mg orally daily (in 3 divided doses)
-Maximum time between doses in the 3 times a day schedule should not exceed 12 hours

-The safety and effectiveness of gabapentin available under the trade name Gralise or Horizant in patients with epilepsy has not been studied.

Use: Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization

Usual Adult Dose for Postherpetic Neuralgia:

-Initial dose: 300 mg orally on day one, 300 mg orally 2 times day on day two, then 300 mg orally 3 times a day on day three
-Titrate up as needed for pain relief
-Maximum dose: 1800 mg per day (600 mg orally 3 times a day)
Gabapentin available under the trade name Gralise:
-Maintenance dose: Gralise should be titrated to 1800 mg orally once daily with the evening meal.
-Recommended titration schedule:
Day 1: 300 mg orally with the evening meal
Day 2: 600 mg orally with the evening meal
Days 3 through 6: 900 mg orally with the evening meal
Days 7 through 10: 1200 mg orally with the evening meal
Days 11 through 14: 1500 mg orally with the evening meal
Day 15: 1800 mg orally with the evening meal

COMMENT:
-Gralise is not interchangeable with other gabapentin products because of differing pharmacokinetic profiles that affect the frequency of administration.

Gabapentin enacarbil extended release tablets are available under the trade name Horizant:

-The recommended dosage is 600 mg orally 2 times a day. Therapy should be initiated at a dose of 600 mg orally in the morning for 3 days of therapy, then increased to 600 mg 2 times a day (1200 mg/day) on day four.

COMMENT:
Gabapentin enacarbil extended release tablets available under the trade name Horizant and gabapentin are not interchangeable.

Use: Postherpetic neuralgia

Usual Adult Dose for Restless Legs Syndrome:

Gabapentin enacarbil available under the trade name Horizant:
600 mg orally once daily with food at about 5 PM

Use: For the treatment of moderate-to-severe primary Restless Legs Syndrome (RLS) in adults

Usual Pediatric Dose for Epilepsy:

Less than 3 years: Not recommended

Greater than or equal to 3 and less than 12 years:
Starting Dose: Ranges from 10 to 15 mg/kg/day in 3 divided doses
Effective Dose: Reached by upward titration over a period of approximately 3 days; the effective dose in patients 5 years of age and older is 25 to 35 mg/kg/day in divided doses (3 times a day).

The effective dose in pediatric patients ages 3 and 4 years is 40 mg/kg/day and given in divided doses (3 times a day). Gabapentin may be administered as the oral solution, capsule, or tablet, or using combinations of these formulations. Dosages up to 50 mg/kg/day have been well tolerated in a long term clinical study. The maximum time interval between doses should not exceed 12 hours.

Greater than 12 years:
-Initial dose: 300 mg orally on day one, 300 mg orally 2 times a day on day two, then 300 mg orally 3 times a day on day three
-Maintenance dose: 900 to 1800 mg orally in 3 divided doses; the dose may be increased up to 1800 mg/day. Dosages up to 2400 mg/day have been well tolerated in long term clinical studies. Doses of 3600 mg/day have also been administered to a small number of patients for a relatively short duration, and have been well tolerated. The maximum time between doses in the three times a day schedule should not exceed 12 hours.

Use: Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization in patients 3 years of age and older

Gabapentin is used together with other medicines to treat partial seizures in adults and children at least 3 years old.

Gabapentin is also used to treat neuropathic pain (nerve pain) caused by herpes virus or shingles (herpes zoster) in adults.

Use only the brand and form of gabapentin your doctor has prescribed. Check your medicine each time you get a refill to make sure you receive the correct form.

The Gralise brand of gabapentin is indicated for the management of neuropathic pain only. It is not used for epilepsy.

Horizant is used to treat nerve pain and restless legs syndrome (RLS).

The Neurontin brand is used to treat seizures in adults and children who are at least 3 years old, in addition to neuropathic pain.

Gabapentin is part of its own drug class, called gabapentinoids. Typical dosages range from 100 milligrams to 800 milligrams of the drug.

 

Is Gabapentin Considered a Painkiller?

Gabapentin is commonly used to treat some types of nerve pain but is classified as an anticonvulsant medicine, not as an opioid or painkiller.

Gabapentin is used with other medications to prevent and control seizures. It is also used to relieve nerve pain following shingles (a painful rash due to herpes zoster infection) in adults. Gabapentin is known as an anticonvulsant or antiepileptic drug.

Gabapentin was first approved in 1993 and is used to treat:

    • postherpetic neuralgia, a nerve pain caused by the shingles virus (herpes zoster),
    • restless legs syndrome (RLS), a painful movement disorder in the legs
    • partial seizures in adults and children at least 3 years old who have epilepsy

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

Gabapentin is not a federally-controlled drug substance and does not contain an opioid (narcotic) medication. However, gabapentin misuse and abuse has been reported, and it may be restricted in some states through their state drug-monitoring program. Gabapentin abuse can boost the high a person gets from opioid painkillers, muscle relaxants, and anxiety medications. This can be dangerous and potentially life-threatening.

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 medicine or CNS depressants, people with chronic obstructive pulmonary disease (COPD, and the elderly.
    • These serious breathing problems may be fatal.
    • Read more about this serious FDA warning here.

Avoid or limit the use of alcohol (in beverages or medicines) with gabapentin as it can worsen drowsiness or dizziness. Ask you doctor about drinking alcohol while you are taking gabapentin.

What type of pain does gabapentin treat?

Gabapentin is approved by the FDA to treat:

Postherpetic neuralgia: nerve pain that can occur due to an outbreak of shingles. Shingles, also known as herpes zoster, occurs when the chicken pox virus deep-seated in your nerve activates again later in life and causes a serious skin rash. Not everyone gets postherpetic neuralgia from shingles, but it can be painful if you do. It causes a burning nerve pain that lasts for months, or even years, after the rash and blisters have cleared up.

Restless legs syndrome (RLS): an uncontrollable urge to move your legs around, often at night. This is usually due to leg discomfort. It may occur most often when you are sitting, laying down, or during bedtime. It can be disruptful to sleep and travel. It is thought RLS may occur due to an imbalance of the chemical dopamine in the brain.

Gabapentin has also been used off-label for the treatment of other types of neuropathic (nerve) pain like peripheral diabetic neuropathy, fibromyalgia and trigeminal neuralgia. “Off-label” uses of gabapentin are uses that have not been approved by the FDA and are not found in the package insert, but may have been accepted for use by healthcare providers based on clinical use.

How does gabapentin come?

There are several brand names of gabapentin including Gralise, Horizant, and Neurontin. Use only the brand and form of gabapentin your doctor has prescribed.

Gralise (gabapentin) is indicated for the management of postherpetic neuralgia only. It is not used for epilepsy. Gralise comes as a 300 and 600 milligram (mg) extended-release (ER) tablet and in a 30-day starter pack of 78 tablets. A generic option is not yet available.

Horizant (gabapentin enacarbil) is used in adults to treat either nerve pain due to postherpetic neuralgia (PHN) or restless legs syndrome (RLS). Horizont is also an extended-release 300 mg or 600 mg tablet and is not interchangeable with other gabapentin products. A generic option is not yet available.

Neurontin (gabapentin) is an immediate-release form used to treat seizures in adults and children who are at least 3 years old, in addition to nerve pain due to shingles. It comes as 100, 300, or 400 mg oral capsules; 600 mg and 800 mg oral tablets, and as a 250 mg per 5 mL oral solution. It is also available as a generic option.

Some brands are only used for certain conditions, and these products may not be interchangeable. Check your medicine each time you get a refill to make sure you have received the correct form.

Some of these medicines may be expensive. Ask your healthcare provider if you are able to use a generic form of gabapentin for your condition (this may not always be possible). Generic options could save you hundreds of dollars each month, or may be less expensive than your insurance copay.

Also, check with the manufacturer who may offer copay cards or patient assistance programs to lessen your overall costs, if you qualify. Be sure to check for online coupons, too, that can save you money on both generics and brands.

To learn more about gabapentin, join the Drugs.com gabapentin Support Group and Q&A Section where you can ask questions, share experiences and keep up with the latest news.

This is not all the information you need to know about gabapentin for safe and effective use and does not take the place of talking to your doctor about your treatment. Review the full gabapentin information here, and discuss this information and any questions you have with your doctor or other health care provider.

What are the Precautions When Taking Gabapentin (Neurontin®)?

Gabapentin (brand name: Neurontin) is a generic prescription drug that is FDA-approved as an add-on treatment with other medications for partial seizures in those with epilepsy. It can also be used to treat nerve pain from postherpetic neuralgia (a complication of shingles).  Gabapentin is frequently prescribed off-label for many other conditions, such as diabetic peripheral neuropathy, fibromyalgia, and alcohol dependence. 

Gabapentin is an anticonvulsive medication that originally saw use as a muscle relaxer and anti-spasmodic medication, but later it was discovered it had the potential of the medication as anticonvulsive medication and as an adjunct to more potent anticonvulsants. It is also useful in certain types of neural pain control. This activity outlines the indications, mechanism of action, dosing, significant adverse effects, contraindications, monitoring, and toxicity of gabapentin and increases practitioners’ knowledge about how to approach this medication and all health professionals in how to monitor it to drive better patient outcomes.

Gabapentin is typically prescribed as a generic, but the drug is also available under the brand names Neurontin and Gralise. Some patients may be prescribed drugs very similar to gabapentin—such as Horizant (gabapentin enacarbil) or Lyrica (pregabalin)—instead of gabapentin. 

Gabapentin is taken as a tablet, capsule, or oral liquid. Dosing will depend on the condition being treated, age of the person being treated, and kidney function. The usual dose for epilepsy starts at 300 mg on the first day. The dose can then be increased until an effective dose is reached, which is usually 300 to 600mg taken three times per day.

Forms and Strengths

Gabapentin Forms and Strength
Gabapentin Forms and Strength

Generic: Gabapentin

    • Form: oral capsule
    • Strengths: 100 mg, 300 mg, 400 mg

Brand: Neurontin

    • Form: oral capsule
    • Strengths: 100 mg, 300 mg, 400 mg

Dosage for postherpetic neuralgia

Adult dosage (ages 18–64 years)

  • Typical starting dosage: Day 1, 300 mg; day 2, 600 mg (300 mg two times per day, spaced evenly throughout the day); day 3, 900 mg (300 mg, three times per day, spaced evenly throughout the day). Your doctor may further increase your dosage after day 3.
  • Maximum dosage: 1,800 mg per day (600 mg, three times per day, spaced evenly throughout the day)

Child dosage (ages 0–17 years)

Dosage for people younger than 18 years has not been established.

Senior dosage (ages 65 years and older)

Your kidney function may decrease with age. Your body may get rid of this drug more slowly. Your doctor may start you on a lower dose so that too much of this drug does not build up in your body. Too much of the drug in your body can be dangerous. Your doctor may change your dose based on how well your kidneys are working.

This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using Gabapentin (buy neurontin® online), tell your doctor or pharmacist your medical history, especially of: kidney disease, mental/mood problems (such as depression, thoughts of suicide), use/abuse of drugs/alcohol.

This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Limit alcoholic beverages.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially swelling of the hands/ankles/feet, dizziness, or loss of coordination. Dizziness and loss of coordination can increase the risk of falling.

Children may be more sensitive to the side effects of this drug, especially mental/mood/behavior changes (such as hostility, problems concentrating, restlessness).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

Gabapentin passes into breast milk. Consult your doctor before breast-feeding.

Gabapentin OVERDOSE

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, labored 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 diarrhea were observed. All patients recovered with supportive care. Coma, resolving with dialysis, has been reported in patients with chronic renal failure who were treated with NEURONTIN.

Gabapentin can be removed by hemodialysis. Although hemodialysis has not been performed in the few overdose cases reported, it may be indicated by the patient’s clinical state or in patients with significant renal impairment.

If overexposure occurs, call your poison control center at 1-800-222-1222.

 

Gabapentin may interact with other medications

 

Gabapentin oral capsule can interact with several other medications. Different interactions can cause different effects. For instance, some can interfere with how well a drug works, while others can cause increased side effects.

Below is a list of medications that can interact with gabapentin. This list does not contain all drugs that may interact with gabapentin.

Before taking gabapentin, be sure to tell your doctor and pharmacist about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Pain drugs

When used with gabapentin, certain pain drugs can increase its side effects, such as tiredness. Examples of these drugs include:

  • morphine

Stomach acid drugs

When used with gabapentin, certain drugs used to treat stomach acid problems can reduce the amount of gabapentin in your body. This can make it less effective. Taking gabapentin 2 hours after taking these drugs can help prevent this problem. Examples of these drugs include:

  • aluminum hydroxide
  • magnesium hydroxide

Important considerations for taking gabapentin

 

Keep these considerations in mind if your doctor prescribes gabapentin oral capsule for you.

General

Gabapentin oral capsules can be taken with or without food. Taking them with food can help to reduce upset stomach.

Storage

  • Store gabapentin at room temperature between 68°F and 77°F (20°C and 25°C).
  • Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

  • Always carry your medication with you, such as in your carry-on bag.
  • Don’t worry about airport X-ray machines. They can’t hurt your medication.
  • You may need to show airport staff the pharmacy label for your medication. Be sure to carry with you the prescription-labeled box that your medication came in.
  • Do not put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

Your doctor will monitor your kidney function.

Insurance

Many insurance companies require a prior authorization for gabapentin. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.