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Gabapentin

Key takeaways:

Gabapentin (Neurontin) is an antiseizure medication. It’s also used for nerve pain from shingles. Other long-acting forms called Gralise and Horizant are also available.

For adults, your gabapentin dosage varies depending on your medical conditions and which form you’re taking. The maximum dosage is 3,600 mg per day. For children, the dosage is based on age and body weight.

There are several ways to save on gabapentin. For instance, GoodRx can help you access Horizant at an exclusive cash price of about $170. Manufacturer savings cards are also available.

What is Gabapentin

Gabapentin (Neurontin) is a widely used medication. It’s FDA approved to treat a certain type of seizures called focal (partial) onset seizures. It also treats postherpetic neuralgia (nerve pain caused by shingles). Additionally, gabapentin is often used off-label for conditions such as anxiety, fibromyalgia, and alcohol use disorder.

Extended release (ER) forms of gabapentin, called Horizant and Gralise, are also available. Horizant and Gralise are both FDA approved for postherpetic neuralgia, and Gralise is also approved to treat restless legs syndrome.

If you’ve been prescribed gabapentin, Horizant, or Gralise, taking your medication correctly is vital to getting the most out of it. And using the correct dosage will help you minimize, or avoid, side effects. In this guide, we’ll review common gabapentin dosages. But keep in mind your healthcare professional might have you take gabapentin differently than what’s outlined below.

What’s the typical gabapentin dosage for adults?

The typical gabapentin dosage for adults depends on why you’re taking it. It also depends on your response to the medication and whether you’re taking an ER or IR gabapentin product. The available gabapentin forms are as follows:

Immediate-release (IR) gabapentin (Neurontin): capsules, tablets, oral solution

Horizant: tablets

Gralise: tablets

Gralise and Horizant tablets are ER products. So they aren’t directly interchangeable with IR gabapentin.

In many cases, your prescriber will start you on a lower gabapentin dosage and then increase it over time. This helps your body get used to gabapentin and minimizes the risk of side effects.

Postherpetic neuralgia

The typical gabapentin dosage for postherpetic neuralgia is below.

Schedule	Recommended dosage
Day 1	300 mg taken as a single dose
Day 2	300 mg twice a day
Day 3	300 mg three times a day

Depending on your response to gabapentin, your prescriber may slowly increase your dosage to 600 mg 3 times a day (for a total of 1,800 mg per day). The maximum dosage of gabapentin is 3,600 mg per day. However, doses greater than 1,800 mg per day haven’t been shown to be more effective than lower doses. The capsules, tablets, and solution can be taken with or without food.

The Gralise dosage for postherpetic neuralgia is detailed below. It should be taken with your evening meal to improve absorption. The maximum recommended dose is 1,800 mg per day.

Schedule	Recommended dosage
Day 1	300 mg once daily
Day 2	600 mg once daily
Days 3 to 6	900 mg once daily
Days 7 to 10	1,200 mg once daily
Days 11 to 14	1,500 mg once daily
Day 15 and after	1,800 mg once daily

Horizant tablets should also be taken with food for best absorption. The typical regimen is below.

Schedule	Recommended dosage
Day 1-3	600 mg once daily in the morning
Day 4 and onward	600 mg twice daily

The maximum recommended dosage of Horixant is 1,200 mg per day. Higher doses haven’t been shown to be more effective, and they’re more likely to cause side effects.

Epilepsy with partial onset seizures

The typical starting dosage of gabapentin for seizures is 300 mg by mouth three times a day, with or without food. Your prescriber may adjust your gabapentin dosage to up to 600 mg 3 times a day (1,800 mg per day). The maximum gabapentin dosage is 3,600 mg per day, but higher doses are more likely to cause side effects.Restless legs syndrome

Horizant is the only gabapentin product that’s approved for restless legs syndrome (RLS).The typical dosage is 600 mg by mouth once daily at about 5PM with food. Taking it at 5PM allows Horizant to start working before you go to sleep, when RLS symptoms are often the most severe.

Some research shows higher Horizant dosages aren’t more effective at treating RLS. But other research shows that taking 1,200 mg daily may be more effective than taking 600 mg daily, especially if the person has trouble sleeping due to RLS. Still, it’s important to know that common gabapentin side effects, such as drowsiness and dizziness, are more likely with higher doses.

What’s the typical gabapentin dosage for children?

All gabapentin IR products are FDA approved to treat focal onset seizures in children ages 3 to 11 years old. The capsules and tablets can also be used in adolescents and teens ages 12 through 17 years old.

Children ages 3 to 11 years old

The typical starting dose is 10 mg/kg to 15 mg/kg of body weight per day, split into 3 doses throughout the day. Over the course of a few days, your child’s prescriber may increase their dose to:

40 mg/kg of body weight per day (for 3 to 4 years olds)

25 mg/kg to 35 mg/kg of body weight per day (for 5 to 11 year olds)

The total daily dose is typically split into 3 doses per day.

Children ages 12 to 17 years old

The typical gabapentin dosage for this age group is the same as adults. The starting dosage is 300 mg three times daily, and may be increased to 600 mg 3 times daily.

How long should you wait between gabapentin doses?

If you’re taking gabapentin more than once a day, it’s best to space out your doses as evenly as you can. Taking them too close together could put you at a higher risk for side effects. Doing so can also make gabapentin less effective since only so much of it can be absorbed at once.

However, waiting too long in between doses can leave your condition under treated. If you’re taking IR gabapentin for seizures, it’s especially important to take your doses consistently. At most, you shouldn’t wait more than 12 hours between doses. Typically, doses shouldn’t be more than 8 hours apart since gabapentin is usually taken 3 times a day for seizures.

Another reason to space your gabapentin doses evenly is that going more than 12 hours between doses can lead to withdrawal symptoms, such as anxiety and restlessness.

Are there any dosage adjustments for medical conditions?

Your body gets rid of gabapentin through your kidneys. If you have kidney problems, your prescriber may adjust your dosage. This can help prevent too much gabapentin from building up in your body and causing side effects.

Dosage adjustments are typically determined by creatinine clearance. This is a lab test that’s used to estimate your kidney function. Usually, a lower creatinine clearance indicates worse kidney function. Below, we’ll cover dosage adjustments for each gabapentin product.

IR gabapentin

The typical dosage adjustments in people ages 12 and older with kidney problems are detailed below. Gabapentin hasn’t been studied in children under 12 years old with kidney problems.

Creatinine clearance (mL/min)	Recommended dosage
30–59	400 mg-1,400 mg per day, split into 2 doses
15–29	200 mg-700 mg as 1 dose per day
Less than 15*	100 mg-300 mg as 1 dose per day

*Your dose will be lowered in proportion to your creatinine clearance

Gralise

The typical starting dose of Gralise is 300 mg by mouth daily. Then, your maintenance dose depends on your creatinine clearance.

Creatinine clearance (mL/min)	Recommended dosage
30–60	600 mg-1,800 mg
Less than 30, or receiving hemodialysis	Not recommended

Horizant

Adjustments recommended for postherpetic neuralgia and RLS are detailed below.

Creatinine clearance (mL/min)	Recommended dosage for postherpetic neuralgia	Recommended dosage for RLS
30–59	300 mg in the morning for 3 days, followed by 300 mg to 600 mg twice daily	300 mg-600 mg daily
15–29	300 mg in the morning on day 1 and day 3, followed by 300 mg once to twice daily	300 mg daily
Less than 15	300 mg every other day to every day in the morning	300 mg every other day
Less than 15 and on hemodialysis	300 mg to 600 mg following every dialysis	Not recommended

What happens if you miss a dose of gabapentin?

If you forget to take your gabapentin dose, what you should do depends on which form you’re taking:

IR gabapentin: Take your missed dose as soon as you remember. If it’s almost time for your next dose, skip your missed dose and take the next dose at the regular time.

Gralise: Take your missed dose with food as soon as you remember. But if you don’t remember until the next day, skip the missed dose and take the next dose at the regular time.

Horizant: Skip your missed dose, and take the next dose at your regular time the following day.

What should you do if you take too much gabapentin?

Taking too much gabapentin could lead to side effects like double vision, tremor, and drowsiness. Dizziness, tiredness, and diarrhea are also possible.

In more serious cases, you could have breathing problems and experience an overdose. This can happen from taking too much gabapentin alone, or combining it with sedative medications. Examples include opioids and benzodiazepines, even at usual doses. Taking gabapentin with alcohol can also increase your risk of breathing problems and overdose.

If you or your child accidentally took too much gabapentin, go to your nearest emergency room or call Poison Control at 1-800-222-1222.

How to save on gabapentin

There are ways to save on gabapentin, which is available as a generic- and brand-name medication. GoodRx can help you navigate between GoodRx coupons and copay savings cards to save money on your prescription.

Save with GoodRx: A 30-day supply of generic gabapentin may cost as little as $10.65 with a free GoodRx coupon. What’s more, anyone with a valid prescription can use GoodRx to purchase a 30-day supply of Horizant at an exclusive cash price of about $170.

Save with a copay savings card: If you have commercial insurance, you may be eligible to pay as little as $0 for Horizant or $20 for Gralise using a savings card from the manufacturer.

FAQ's

What is the highest dosage of gabapentin that’s safe?

In general, the maximum dose of IR gabapentin per day is 3,600 mg. This is typically divided into 3 doses. However, doses this high aren’t always more effective than lower doses. And they tend to cause more side effects, like drowsiness and dizziness.

The best gabapentin dosage for you depends on what you’re treating, and other factors such as whether you have existing kidney problems or take medications that may interact with gabapentin.
What are the most common side effects of gabapentin?

The most common side effects of gabapentin are dizziness and drowsiness. This can raise your risk for falls and injuries.

Often, these side effects improve as your body gets used to gabapentin. But if drowsiness and dizziness are preventing you from carrying out your daily tasks, talk to your prescriber. You should also tell them if you’re experiencing other side effects, such as fluid buildup (edema), weight gain, or mood changes.

How do you take gabapentin?

Gabapentin capsules should be taken with water, with or without food. Horizant and Gralise should be taken with food because this helps them be absorbed by the body better.

Gabapentin tablets can be split in half (unlike Horizant and Gralise). But you shouldn’t open the capsules. If you cut your IR gabapentin tablet, be sure to take the other half within 28 days.

One Final Note..

Your gabapentin (Neurontin) dosage depends on why you’re taking it, and other factors such as whether you have typical kidney function. It also depends on whether you’re taking gabapentin immediate-release, or an extended-release version such as Horizant or Gralise.

When starting gabapentin, your prescriber will typically initiate a lower dose and then increase your dose over a few days to weeks. This helps your body get used to gabapentin, and minimizes the risk of side effects.

Space your gabapentin doses as evenly as possible. If you’re not sure how long to wait between gabapentin doses, ask your prescriber. Doses taken 3 times a day should be taken no more than 8 hours apart. And going more than 12 hours without a dose is typically not recommended, since this can leave your condition undertreated and cause withdrawal symptoms.

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Most recent revision June 06, 2025 03:35:41 PM