Gabapentin Dosages: Your GoodRx Guide
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.
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Table of contents
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.
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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.
Gabapentin side effects: Common gabapentin side effects include drowsiness, dizziness, and swelling. Learn about what to expect if you’re taking gabapentin.
Gabapentin FAQs, answered: Knowing how long gabapentin takes to work, and what to expect while taking it, can help you get a better understanding of your treatment.
Gabapentin drug interactions. Gabapentin can interact with other medications and substances, such as opioids and alcohol. Learn what to avoid with gabapentin.
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 undertreated. 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 $10.80 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.
Frequently asked questions
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.
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.
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.
The bottom line
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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References
Almatica Pharma LLC. (2024). Gralise - gabapentin tablet, film coated [package insert].
Azurity Pharmaceuticals, Inc. (2023). Horizant - gabapentin enacarbil tablet, extended release [package insert]. DailyMed.
Bockbrader, H. N., et al. (2012). A comparison of the pharmacokinetics and pharmacodynamics of pregabalin and gabapentin. Clinical Pharmacokinetics.
Bryant Ranch Prepack. (2024). Gabapentin - gabapentin solution [package insert].
Kume, A. (2014). Gabapentin enacarbil for the treatment of moderate to severe primary restless legs syndrome (Willis-Ekbom disease): 600 or 1,200 mg dose? Neuropsychiatric Disease and Treatment.
MedlinePlus. (2020). Gabapentin.
Northstar Rx LLC. (2024). Gabapentin - gabapentin capsule [package insert].
Quallent Pharmaceuticals Health LLC. (2024). Gabapentin - gabapentin tablet, film coated [package insert].
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