What is gabapentin?

Gabapentin is a prescription medication known as a gamma aminobutyric acid (GABA) analogue. GABA reduces the excitability of nerve cells (neurons) in the brain, which play a role in seizures and the transmission of pain signals. Gabapentin mirrors the effects of GABA calming excited neurons.

Gabapentin is in a class of medications called anticonvulsants.

What are the brand names of gabapentin?

Gabapentin is available as both a brand name product and a generic product (chemically the same, usually lower cost than the brand name product). Brand names of gabapentin include Horizant®, Gralise® and Neurontin®.

What is gabapentin approved for?

Gabapentin is used to:

• Prevent and control partial seizures. Gabapentin can be used in adults and children age 3 and older who have partial seizures.
• Relieve nerve pain following shingles in adults. Shingles is a painful rash that develops many years after you've had chickenpox. The virus that causes chickenpox stays dormant in a portion of your spinal nerve root called the dorsal root ganglion. For whatever reason, this otherwise dormant virus gets reactivated — usually by stress — causing a shingles rash. Nerve pain following a case of shingles is called postherpetic neuralgia (PHN).
• Treat moderate-too-severe primary restless legs syndrome.

The branded gabapentin products Neurontin and Gralise are approved for partial seizures and PHN. The branded gabapentin enacarbil product Horizant is approved for restless legs syndrome and PHN.

What dosage strengths and forms does gabapentin come in?

Gabapentin is available as:

• Gabapentin tablets. It’s available as 300- and 600-milligram tablets (Gralise) and 600- and 800-milligram tablets (Neurontin or generic gabapentin).
• Gabapentin oral solution. The oral solution contains 250 millgrams of gabapentin per 5 milliliter (50 mg per mL) Neurontin or generic gabapentin.
• Gabapentin capsules. It’s available as 100-, 300- or 400-milligram gelatin capsules (Neurontin or generic gabapentin).
• Gabapentin enacarbil, 300- and 600-milligram extended-release tablets (Horizant).

How should I take gabapentin?

• Take Gralise tablets with your evening meal. Swallow tablets whole with a full glass of water. Don't chew, break or crush.
• Take Horizant tablets with food. Swallow tablets whole with a full glass of water. Don't chew, break or crush.
• Take other forms of gabapentin with or without food.
• Neurontin and generic forms of Neurontin tablets may be broken into two pieces. You can take the second half for your next dose. Don't use the half-tablet beyond 28 days after the whole tablet was cut or broken.
• Carefully measure the liquid formulation of gabapentin using the measuring device that comes with the drug. If you did not receive a measuring device, please ask your pharmacist for a medication-measuring device.
• If you take an aluminum or magnesium-containing antacid, such as Maalox®, Mylanta®, Gelusil®, Gaviscon®, or Di-Gel®, wait at least two hours before taking your next dose of gabapentin.
• Take gabapentin exactly as prescribed by your healthcare provider.

What are the serious side effects of gabapentin?

If you have any of these symptoms, call your healthcare provider right away:

• Signs of an allergic reaction: If you have a skin rash, hives, itching or swollen, blistered or peeling skin with or without fever contact your healthcare provider. You should also contact your provider if you have trouble breathing or swallowing, wheezing or swelling of your face, lips, throat, eyes, mouth or tongue
• Changes in mood or behavior: Call your provider for any suicidal thoughts or thoughts about dying, suicide attempts, new or worsening depression, anxiety, irritability or feelings of agitation or restlessness. You should also call your provider for trouble sleeping, panic attacks, feelings of aggression or anger, impulsive behavior, extreme increase in activity or talking and other changes in mood or behavior, confusion, inability to focus or memory problems as these can be side effects of your medication.
• Signs of liver abnormalities: Yellowing of your skin or whites of your eyes, dark urine, light-colored stools, vomiting, unusual bleeding or bruising.
• Signs of kidney abnormalities: Trouble urinating, a change in how much urine is passed, blood in your urine, or weight gain and swelling of legs and feet from retaining fluid.
• Other concerning abnormalities: Change in color of your skin to a bluish color on your lips, nail beds, fingers, or toes along with severe fatigue or weakness and unexpected muscle pain.

What are the more common side effects of gabapentin?

Common side effects of gabapentin include:

• Feeling tired.
• Dizziness.
• Headache.
• Nausea and vomiting.
• Fever.
• Difficulty speaking.
• Recurring infections.
• Memory loss.
• Weight gain.
• Movement problems: coordination problems, being unsteady, tremors, jerky movements.
• Eye problems: unusual eye movements, double vision.

Talk to your healthcare provider if any side effects do not go away.

Are there any serious interactions with gabapentin and other medications?

Serious breathing problems can happen if you take gabapentin with drugs that cause severe sleepiness or decreased awareness. Some examples include narcotic opioids, anti-anxiety medicines, antidepressants, and antihistamines. If you are 65 years of age or older and/or have a condition that affects your lungs, such as chronic obstructive pulmonary disease (COPD), there is an increased risk for breathing problems. Watch for increased sleepiness or decreased breathing when you start taking gabapentin or when the dose is increased. Get help right away if you develop breathing problems.

Seek immediate medical attention if these symptoms develop:

• Confusion.
• Unusual dizziness or lightheadedness.
• Slowed, shallow or trouble breathing.
• Unresponsiveness (can’t wake up).
• Bluish-colored or tinted skin, especially on lips, fingers or toes.

What other medications and products can interact with gabapentin?

Products that interact with gabapentin include:

• Alcohol.
• Antihistamine-containing cold, cough and allergy products.
• Certain medicines for anxiety or sleep.
• Certain medicines for depression, such as amitriptyline, fluoxetine and sertraline.
• Certain medicines for seizures, such as phenobarbital and primidone.
• Certain medicines for stomach problems. (Wait two hours after taking aluminum and magnesium-containing antacids before taking gabapentin.)
• General anesthetics, local anesthetics, or muscle relaxants given before surgery.
• Narcotic pain medicines.

Can I drink alcohol while taking gabapentin?

Avoid drinking alcohol while taking gabapentin. Drinking alcohol with gabapentin could increase sleepiness or dizziness.

What else do I need to know about gabapentin?

Never stop taking gabapentin without talking to your healthcare provider first. Stopping gabapentin suddenly can cause serious problems, including increasing your risk of seizures (if you are taking gabapentin to control seizures) or not improving your symptoms (if taking gabapentin for other indications). Also, never change your dose without talking to your provider first. Always take gabapentin exactly as prescribed.

Don’t drive, operate heavy machinery or do other dangerous activities after taking gabapentin until you know how it affects you.

Read the full prescription information leaflet that comes with your medication. Never hesitate to ask your healthcare provider or pharmacist if you have any questions about gabapentin.

What should I tell my healthcare provider before starting gabapentin?

Tell your healthcare provider if you:

• Have lung or breathing problems.
• Have diabetes.
• Have kidney problems or are on dialysis.
• Have or had mood problems, depression, suicidal thoughts or behavior.
• Have a history of drug abuse or alcohol abuse problems.
• Are pregnant, trying to become pregnant or are breastfeeding.

Inform your providers of all medications you take, including prescription and over-the-counter, as well as supplements, vitamins and herbal products.

Can I take gabapentin if I’m pregnant or thinking of becoming pregnant?

It’s unknown if gabapentin can harm your unborn baby. For this reason, talk to your healthcare provider as soon as you know you are pregnant. You and your healthcare provider will determine if you should take gabapentin during your pregnancy or change to a different medication.

Does gabapentin pass into breast milk?

Yes, gabapentin does pass into breast milk. If you are breastfeeding or planning to breastfeed, talk with your healthcare provider about breastfeeding or medication options.

Is gabapentin a narcotic or controlled substance?

Gabapentin is not a narcotic. It's not classified as a controlled substance in most states. (Kentucky, West Virginia, Michigan, Tennessee, and Virginia have reclassified gabapentin as a Schedule V controlled substance). Gabapentin is not an opioid.

Is gabapentin addictive?

Gabapentin is not addictive, but this doesn’t mean that gabapentin can’t be abused. A small number of studies have reported misuse and abuse of gabapentin.

Does gabapentin cause withdrawal symptoms?

Gabapentin withdrawal symptoms have been reported since the drug was approved. However, the individuals in these reports experienced symptoms after discontinuing higher-than-recommended doses of gabapentin and for uses for which the drug was not approved.

What’s known about gabapentin and overdose?

Overdoses on gabapentin have been reported. Individuals experienced double vision, slurred speech, drowsiness, diarrhea and sluggishness.

What should I do if I miss a dose of gabapentin?

If you forget to take a dose of gabapentin, take it as soon as you remember. If it’s just a few hours before it’s time to take your next dose, take only one dose. Never take more than one dose in an attempt to catch up. If you have any concerns or questions, be sure to call your healthcare provider or pharmacist right away.