Gabapentin (Neurontin, Gralise, Horizant)

Gabapentin is pronounced GAB-uh-PEN-tin.

Gabapentin (Neurontin, Gralise, Horizant) is FDA-approved to treat certain seizures, nerve pain that can follow shingles, and, in the Horizant form, moderate-to-severe restless legs syndrome. In psychiatric care, it may also be prescribed off-label to help with anxiety, alcohol use disorder, and sleep difficulties.

Gabapentin calms overactive nerve signaling in the brain and nervous system. Its structure is similar to gamma-aminobutyric acid (GABA), a natural brain chemical that quiets nerve activity, although gabapentin does not act on GABA brain receptors directly and it is not known exactly how gabapentin works in the brain. When nerve cells fire too easily, that overactivity can contribute to seizures, and also may be related to nerve pain, and feelings of restlessness or anxiety. Gabapentin may help decrease certain cell activity. Scientifically, gabapentin binds to a specific site (the alpha-2-delta subunit) on calcium channels in nerve cells, which reduces the release of excitatory chemical messengers.

Gabapentin belongs to a class of medications called gabapentinoids, which are also classified as anticonvulsants (seizure medications). Despite what some people assume, gabapentin is not an opioid, a narcotic, a muscle relaxer, or a benzodiazepine.

Gabapentin is not a controlled substance under federal law. However, because of concerns about misuse, some states classify gabapentin as a controlled substance, and many others track gabapentin prescriptions through monitoring programs. Your prescribing clinician can tell you the rules that apply where you live.

Common side effects include:

• Drowsiness and dizziness — the most common effects, especially when starting or after a dose increase; they often lessen as the body adjusts. Avoid driving until you know how gabapentin affects you.
• Unsteadiness or coordination problems — take extra care on stairs or uneven ground, and tell your clinician about any falls.
• Swelling in the legs or feet — mention this to your clinician, especially if you have heart or kidney conditions.
• Weight gain or increased appetite — regular activity and balanced meals can help; discuss any concerns with your clinician.
• Blurred or double vision — often temporary; report changes that persist.
• Fatigue — if tiredness interferes with your day, speak with your clinician about the timing of your dose. Only adjust timing or dosage when recommended by your psychiatric clinician.

Serious side effects — contact your clinician promptly if you experience:

• Slowed, shallow, or difficult breathing, especially if you also take opioid pain medications or other sedating medications
• New or worsening depression, unusual mood changes, or thoughts of self-harm
• Rash together with fever or swollen glands, which can signal a serious allergic reaction
• Severe dizziness, confusion, or extreme sleepiness

Weight gain can occur with gabapentin, though it is less common than other side effects. Some individuals notice increased appetite or the body holding on to extra fluid, which can cause swelling. Discuss any concerns with your clinician.

Yes, drowsiness is one of the most common side effects of gabapentin, especially when first starting the medication or after a dose increase. For many individuals, this lessens as the body adjusts. Because gabapentin can cause drowsiness, some clinicians prescribe it off-label to help with sleep difficulties. Avoid driving until you know how gabapentin affects you.

Gabapentin is not FDA-approved for anxiety, but it is sometimes prescribed off-label for anxiety symptoms. Research reviews suggest gabapentin may help some individuals with certain anxiety conditions, such as social anxiety, although study results are mixed and the evidence is limited. A psychiatric clinician can help determine whether gabapentin or another anxiety treatment fits your needs.

It depends on the condition being treated. For nerve pain, some individuals notice improvement within the first one to two weeks, with fuller benefits over several weeks. When prescribed off-label for anxiety or sleep, calming and drowsiness effects may be felt immediately, but individual responses vary. Take your medication as prescribed and check in regularly with your clinician.

Both gabapentin and Lyrica (pregabalin) are gabapentinoids and work in similar ways. Pregabalin is absorbed more predictably and tends to act at lower doses, while gabapentin has been available longer and is typically less expensive. Lyrica is a federally controlled substance, meaning it has potential to be abused and its prescription is more tightly regulated, while gabapentin is controlled only in certain states. The choice depends on your medical history, symptoms, and side-effect profile.

All three are brand-name forms of gabapentin, but they are not interchangeable. Neurontin is the original form, usually taken multiple times per day, and is approved for seizures and nerve pain after shingles. Gralise is a once-daily extended-release tablet approved only for nerve pain after shingles. Horizant contains gabapentin enacarbil, a form the body converts into gabapentin after it is absorbed, and is approved for restless legs syndrome and nerve pain after shingles. Your prescribing clinician will recommend the form that best fits your treatment needs; do not switch between forms on your own.

Gabapentin is not as strongly associated with addiction as opioids or benzodiazepines, but misuse can occur, particularly among individuals with a history of opioid or other substance misuse. The body can also become used to the medication over time, so stopping suddenly can cause withdrawal-like symptoms. Always follow your psychiatric provider’s directions on when to stop taking medications or change dosages.

Stopping gabapentin too quickly may cause anxiety, restlessness, trouble sleeping, nausea, sweating, and pain. In individuals who take gabapentin for seizures, stopping abruptly can also increase the risk of seizures. Your provider will create a taper plan to lower the dose gradually. Always follow your psychiatric provider’s directions on when to stop taking medications or change dosages.

Gabapentin leaves the body relatively quickly. Most of a dose is removed by the kidneys within about one to two days. It may stay in the body longer in older adults and in individuals with kidney problems.

Try to avoid alcohol while on gabapentin. Alcohol can significantly worsen side effects such as drowsiness, dizziness, and trouble concentrating. Combining gabapentin with alcohol or other sedating substances can also slow breathing, which the FDA has warned can be dangerous. Always discuss alcohol use with your prescribing clinician.

The cost of gabapentin varies depending on whether you are prescribed the generic medication or a brand-name version (Neurontin, Gralise, or Horizant), as well as the form and strength.

• Generic gabapentin: As of publication date, prices range from about $8 to $561 depending on strength and pharmacy.
• Brand-name Neurontin: As of publication date, prices start at about $310.68 for 100 capsules (100 mg).
• Brand-name Gralise: As of publication date, prices start at about $943 for a 90-tablet supply of extended-release tablets.
• Brand-name Horizant: As of publication date, prices are around $556 for 30 extended-release tablets.

If you have insurance, your out-of-pocket cost will depend on your supporting diagnosis and plan type (e.g., commercial, Medicare, Medicaid) and may include a copay or coinsurance.

No, not without the approval of your prescribing psychiatric clinician. Gabapentin can be dangerous when combined with opioid pain medications or other sedating medications, because the combination can cause slowed or difficult breathing. Some antacids can also make gabapentin less effective when taken at the same time. Share a full list of every medication and supplement you take with your clinician.

Yes, overdose is possible, though the intestinal tract has limited ability to absorb very high doses. Symptoms may include extreme drowsiness, slurred speech, double vision, diarrhea, slowed breathing, and the risk is higher when gabapentin is combined with opioids or other sedating substances. If an overdose is suspected, call 911 or Poison Control (1-800-222-1222) right away. Always take gabapentin as prescribed by your clinician.

Gabapentin may be prescribed during pregnancy when the benefits outweigh the risks, but research on its safety in pregnancy is limited. It’s important to discuss the risks and benefits of any medication for both the mother and baby with your healthcare provider.