Gabapentin For Pain Relief

Gabapentin is used to help control partial seizures (convulsions) in the treatment of epilepsy. This medicine cannot cure epilepsy and will only work to control seizures for as long as you continue to take it.

Gabapentin is also used in adults to manage a condition called postherpetic neuralgia, which is pain that occurs after shingles.

Gabapentin works in the brain to prevent seizures and relieve pain for certain conditions in the nervous system. It is not used for routine pain caused by minor injuries or arthritis. Gabapentin is an anticonvulsant.

This medicine is available only with your doctor’s prescription.

This product is available in the following dosage forms:

  • Capsule
  • Tablet
  • Solution
  • Suspension
Gabapentin 300mg
Gabapentin 300mg

All brands of gabapentin are used in adults to treat neuropathic pain (nerve pain) caused by herpes virus or shingles (herpes zoster).

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

The Horizant brand of gabapentin, in addition to treating neuropathic pain, is also used to treat restless legs syndrome (RLS).

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

Important information

Some people have thoughts about suicide while taking this medicine. Children taking gabapentin may have behavior changes. Stay alert to changes in your mood or symptoms. Report any new or worsening symptoms to your doctor.

Do not stop using gabapentin suddenly, even if you feel fine.

Before taking this medicine

You should not use gabapentin if you are allergic to it.

To make sure this medicine is safe for you, tell your doctor if you have ever had:

  • kidney disease (or if you are on dialysis);
  • diabetes;
  • depression, a mood disorder, or suicidal thoughts or actions;
  • a seizure (unless you take gabapentin to treat seizures);
  • liver disease;
  • heart disease; or
  • are taking an anti-depressant or sedating medication; or
  • (for patients with RLS) if you are a day sleeper or work a night shift.

Some people have thoughts about suicide while taking this medicine. Your doctor should check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Seizure control is very important during pregnancy, and having a seizure could harm both mother and baby. Do not start or stop taking gabapentin for seizures without your doctor’s advice, and tell your doctor right away if you become pregnant.

Proper Use of Gabapentin

Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. To do so may increase the chance of side effects.

This medicine comes with a Medication Guide. Read and follow the instructions carefully. Ask your doctor if you have any questions.

If you are using Gralise® tablets:

  • These should be taken with the evening meal.
  • Swallow the tablet whole. Do not crush, break, or chew it.

For patients with epilepsy who take gabapentin three times per day, do not allow more than 12 hours to pass between any 2 doses. The medicine works best if a constant amount is in the blood.

Neurontin® capsules, tablets, and solution may be taken with or without food.

You may break the scored Neurontin® tablets into two pieces, but make sure you use the second half of the tablet as the next dose. Do not use the half-tablet if the whole tablet has been cut or broken after 28 days. Ask your doctor or pharmacist if you have any questions.

Swallow the capsule whole with plenty of water. Do not open, crush, or chew it.

Measure the oral liquid using a marked measuring spoon, oral syringe, or medicine cup. The average household teaspoon may not hold the right amount of liquid.

If you take an antacid that contains aluminum or magnesium, wait at least 2 hours before taking gabapentin. Some examples of these antacids are Di-Gel®, Gaviscon®, Gelusil®, Maalox® and Mylanta®.

Only use the brand of this medicine that your doctor prescribed. Different brands may not work the same way.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage forms (capsules, liquid, and tablets):
    • For epilepsy:
      • Adults and children 12 years of age and older—At first, 300 milligrams (mg) three times per day. Your doctor may adjust your dose as needed. However, the dose is usually not more than 2400 mg per day.
      • Children 3 to 11 years of age—Dose is based on body weight and must be determined by your doctor. The starting dose is 10 to 15 milligrams (mg) per kilogram (kg) of body weight per day and divided in 3 doses. Your doctor may adjust your dose as needed.
      • Children younger than 3 years of age—Use and dose must be determined by your doctor.
    • For postherpetic neuralgia:
      • Adults— At first, 300 milligrams (mg) as a single dose in the evening. Your doctor may adjust your dose as needed. However, the dose is usually not more than 1800 mg per day.
      • Children—Use and dose must be determined by your doctor.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

You should store the Neurontin® oral liquid in the refrigerator. Do not freeze.

Gabapentin side effects

Get emergency medical help if you have signs of an allergic reaction to gabapentin: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Seek medical treatment if you have a serious drug reaction that can affect many parts of your body.Symptoms may include: skin rash, fever, swollen glands, flu-like symptoms, muscle aches, severe weakness, unusual bruising, or yellowing of your skin or eyes. This reaction may occur several weeks after you began using gabapentin.

Call your doctor at once if you have:

  • increased seizures;
  • fever, rash, and/or swollen lymph nodes;
  • severe weakness or tiredness;
  • problems with balance or muscle movement;
  • upper stomach pain;
  • chest pain, new or worsening cough with fever, trouble breathing;
  • severe tingling or numbness;
  • rapid eye movement; or
  • kidney problems – little or no urination, painful or difficult urination, swelling in your feet or ankles.

Some side effects are more likely in children taking gabapentin. Contact your doctor if the child taking this medicine has any of the following side effects:

  • changes in behavior;
  • memory problems;
  • trouble concentrating; or
  • acting restless, hostile, or aggressive.

Common gabapentin side effects may include:

  • headache, dizziness, drowsiness, tiredness;
  • swelling in your hands or feet;
  • problems with your eyes;
  • coordination problems; or
  • (in children) fever, nausea, vomiting.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

FAQs about Gabapentin for Depression, Mania and Anxiety

1. What Exactly is Gabapentin (Neurontin)?

This particular drug is an anticonvulsant. It is not related chemically to other anti-convulsants or other mood regulating drugs on the market.


2. When Did the FDA Approve Gabapentin for marketing in the United States? How Can It Be Promoted?

On December 30, 1993, Gabapentin got final approval, which meant that it could be marketed in the United States. It is only marketed as an anticonvulsant. However, it has also been used for restless leg syndrome, pain issues, hot flashes, tremors, and a wide variety of psychiatric disorders.


3. Is There a Generic Version of Gabapentin Available?

Since its manufacturer no longer has patent protection on the drug, there are generic versions of Gabapentin on the market.


Article continues below

Do you feel depressed?

Take our 2-minute Depression quiz to see if you may benefit from further diagnosis and treatment.

4. What is the Difference Between Gabapentin and Other Mood Stabilizing Medications?

There are two major ways that Gabapentin differs from similar drugs on the market:

  • Gabapentin has been proven to be effective for people who have hard-to-treat depression or other mood disorders
  • The side effects are relatively minor

5. How is Gabapentin Different from Valproate and Carbamazepine?

There are claims that Gabapentin was successful in helping with rapid cycling and mixed bipolar states in people who have not received relief from valproate or carbamazepine. It appeared that Gabapentin helped more with anxiety and agitation than the other two drugs. It has also been shown that Gabapentin could aid people with certain types of tardive dyskinesia.


6. What Types of Mood and Anxiety Disorders Can Best Be Treated with Gabapentin?

Experts say that it is too early to tell which types of disorders will get the best results from Gabapentin. There are not a lot of reports on Gabapentin’s use. Many experts don’t recommend the use of Gabapentin for mood disorders. There is more data from people who have hard-to-treat bipolar disorder than unipolar depression, although some people with unipolar disorder have gotten good results from Gabapentin. In time, it can be proven that Gabapentin can be used to treat a variety of mood disorders.


7. Can Gabapentin Be Used for the Treatment of Mixed Bipolar States? Can It Prevent Future Episodes of Mania and Depression?

Right now, there isn’t a lot of evidence that Gabapentin can be used for treating people with bipolar disorder.


8. Should a Person Take Any Laboratory Tests Before Taking Gabapentin?

Before a patient starts Gabapentin therapy, they should undergo a thorough medical examination to rule out any medical issues. This includes any blood or urine tests. Medical evaluations are important as issues such as thyroid conditions can undermine the therapy.


9. How Do You Initiate Gabapentin Therapy?

The therapy will be started with 300 mg once a day, usually in the evening. The dose will then be increased every 3 to 5 days. Some people will see an increase with 600 mg/day, others will see increases up to 4,800 mg/day.


10. Are There Potential Interaction Issues for People Taking Carbamazepine, Valproate or Lithium?

No interactions between Gabapentin and valproate, carbamazepine or lithium have been reported.


11. What is the Typical Final Dose That Would Be Prescribed to Someone Taking Gabapentin?

If used as a mood stabilizer or anti-depressant, the final dose is usually between 900 and 2,000 mg a day. However, some patients have been known to need up to 4,800 mg a day to get good results.

Gabapentin has a half-life of about six hours, so it must be administered 3 to 4 times a day.


12. How Long Does It Usually Take for Gabapentin to Work?

Some people see improvement in their antigenic and/or anti-depressant symptoms about a week after starting treatment. Others need about a month before they see significant improvement.


13. What Are Gabapentin’s Side Effects?

  • Dizziness
  • Double Vision
  • Fatigue
  • Nystagmus (involuntary eye movement)
  • Sleepiness
  • Tremors
  • Unsteadiness

Most people notice side effects the first few days after an increase in their dose. They usually fade after a while.


14. Are There Any Side Effects That Force People to Stop Taking Gabapentin?

The side effects that are most likely to keep people from continuing Gabapentin therapy are the following symptoms:

  • Dizziness
  • Fatigue
  • Nausea and/or vomiting
  • Sleepiness
  • Unsteadiness

15. Are There Any Psychiatric Side Effects That Come From Taking Gabapentin?

There are some rare side effects, which include the following symptoms:

  • Agitation
  • Decreased libido
  • Depersonalization
  • Increased libido
  • Mania
  • Paranoia

16. Does Gabapentin Interact with Any Other Prescriptions or Over-The-Counter Medications?

There are only a few interaction issues that are known. Antacids have been known to decrease absorption of the drug, as well as lower the blood level by 20%. Gabapentin could also increase the level of concentration of some oral contraceptives by up to 13%. However, these two interaction possibilities are not clinically significant in any way.


17. Are There Any Interaction Issues Between Gabapentin and Alcohol?

Alcoholic beverages have been known to increase the discomfort of Gabapentin’s side effects.


18. Is It Safe for a Woman Who Is Pregnant, About to Become Pregnant, or Nursing to Take Gabapentin?

The FDA placed Gabapentin in pregnancy category C. According to studies done on animals, there was harm done to fetuses. However, there have been no studies done on humans. Despite all this, experts believe that the benefits gained from taking Gabapentin may outweigh its risks.


19. Can Children and Adolescents Safely Take Gabapentin?

In other countries besides the United States, children have been prescribed Gabapentin. However, Gabapentin has only been approved for use in adolescents above the age of 12.


20. Can Elderly People Use Gabapentin?

The elderly seem to experience similar effects to younger people. There isn’t a lot of precedent with using this drug to treat psychiatric disorders in this population.


21. Can Symptoms Occur if Gabapentin is Discontinued?

Like other psychotropic drugs, people should ease off Gabapentin gradually. There are some known withdrawal symptoms. This mostly comes from people who take high doses of the drug and suddenly stop. People should only abruptly discontinue Gabapentin because of a serious side effect.


22. If Taken In Overdose, is Gabapentin Toxic?

There isn’t a lot of data on overdoses. People have been known to survive overdoses of up to 49,000 mg of Gabapentin without serious health consequences.


23. Can This Medication Be Taken with MAO Inhibitors?

This particular combination doesn’t present any special issues.


24. How Much Does Gabapentin Cost?

According to GoodRx.com, generic Gabapentin can cost between $10-$27 for ninety 100mg or 300mg capsules and between $14-$53 for ninety 400mg capsules.


25. Can People Who Received Little Benefit From Other Psychotropic Drugs Get Good Results From Gabapentin?

Gabapentin is mostly used by people with mood or anxiety disorders that have not been adequately treated with other medications.


26. Are There Any Disadvantages to Gabapentin?

There isn’t a lot of available information about side effects. There’s also the fact that Gabapentin’s use with people with mood disorders is relatively new. Because of this fact, it’s not known whether people who initially respond to Gabapentin will continue to do so after years of use.

Because of the short half-life of the medication, people will need to take divided doses throughout the day.

Studies have not been able to prove that Gabapentin is effective as a mood control agent.

This medication can also cause suicidal thinking. This effect is similar to that of other anticonvulsants.


27. Why Do Doctors Prescribe Gabapentin When There Are Other Mood Stabilizing Medications That Have Been Around for Many Years? These Medications Have Been Shown to Be More Effective in Double-Blind Studies That Are Placebo-Controlled.

There are two reasons why physicians prescribe Gabapentin over more established drugs. The first reason is that not everyone improves with the older, more established medications. The second is that some people can’t deal with the side effects of the other drugs.


28. Is Gabapentin Available in Countries Other Than the United States?

Yes. Gabapentin is available in over 40 countries.

Gabapentin for Nerve Pain

Gabapentin has been shown to be beneficial in treating several types of neuropathic pain; however, the mechanism of action by which gabapentin exerts its analgesic effect is still unknown. It is suggested that gabapentin may block the calcium channel alpha(2)delta (a2d)-1 receptor in the brain. This protein-modulated receptor is involved in excitatory synapse formation. Therefore, the therapeutic effects of gabapentin may be attributed to prevention of new synapse formations.

Gabapentin 800mg
Gabapentin 800mg

Gabapentin was shown to offer substantial improvement in neuropathic pain with side effects that were similar to those on placebo.

Even with sufficient data supporting the use of gabapentin in the treatment of various neuropathic pain conditions, gabapentin only has Food and Drug Administration (FDA) approval for PHN. Dosing recommendations for off-label use of gabapentin can be somewhat ambiguous, if a recommendation exists at all. Therefore, several studies further investigate dosing regimens specific to other neuropathic pain syndromes.

Gabapentin Dosing Considerations

Three gabapentin products are FDA approved to treat PHN. The different formulations cannot be interchanged and each has its own dosing schedule.

  • For immediate-release gabapentin (Neurontin), dosing may be initiated with 300 mg on day 1, doubled on day 2 (300 mg twice a day), and tripled on day 3 (300 mg 3 times a day). The dose can then be titrated up as needed for pain relief to a maximum dose of 1,800 mg daily (divided into 3 daily doses). Clinical studies referenced in the package insert state that efficacy for a range of doses from 1,800 mg/day to 3,600 mg/day were observed; however, there was no additional benefit seen with doses greater than 1,800 mg/d.
  • Gralise is an extended-release gabapentin formulation that also is FDA approved for PHN with a titration schedule that begins with 300 mg on day 1; 600 mg on day 2; 900 mg on days 3 to 6; 1,200 mg on days 7 to 10; 1,500 mg on days 11 to 14; and 1,800 mg on day 15 and thereafter.2
  • The third gabapentin formulation for PHN treatment is another extended-release product, Horizant. The starting dose is 600 mg in the morning for 3 days, increased to 600 mg twice daily on day 4 and thereafter. A daily dose of Horizant greater than 1,200 mg provided no additional benefit at the expense of side effects.3

Several studies have evaluated off-label use of gabapentin in the treatment of other neuropathic pain conditions. A randomized, double-blind trial compared gabapentin to placebo in 135 patients with DPN over 8 weeks. The results showed a statistical benefit of gabapentin compared to placebo, at all end points, for pain improvement.4 The gabapentin dosing regimen used in this study was 900 mg/d for week 1; 1,800 mg/d for week 2; 2,400 mg/d for week 3; and 3,600 mg/d for week 4. All the patients were titrated up to a dose of 3,600 mg/d, regardless of efficacy at lower doses. Patients who could not tolerate this dose were titrated down to the greatest tolerable dose.

Of the 84 patients randomized to the gabapentin group, 56 (67%) were able to tolerate 3,600 mg/d.During the first week, gabapentin resulted in improvement in sleep interference compared to placebo. By the second week, gabapentin resulted in improvement in all pain rating scales compared to placebo. Of the 84 patients in the gabapentin group, 70 completed the study, and 7 patients withdrew due to adverse drug events (ADEs). Most ADEs reported in the gabapentin group were of mild or moderate intensity, and the most frequently reported effects were dizziness (23.8%), somnolence (22.6%), headache (10.7%), diarrhea (10.7%), confusion (8.3%), and nausea (8.3%).

A double-blind crossover study (n=40) assessed gabapentin for the treatment of DPN. The dose of gabapentin used in this trial was much lower, with patients titrated up every
3 days to a maximum dose of 900 mg/d. The end points evaluated in this study included level of pain on a visual analog pain scale (VAS), and scores on the present pain intensity scale, the McGill pain questionnaire (MPQ), and the global assessment of pain relief. Statistical improvement between gabapentin and placebo was noted in only 1 end point, the MPQ score, with a mean reduction of 8.9 points for gabapentin compared to 2.2 points with placebo (P=0.03). No serious ADEs were noted, and the most common ADEs of gabapentin were drowsiness, fatigue, and imbalance. The results of this study suggest that gabapentin is not effective or is only minimally effective in treating painful DPN at a dose of 900 mg/d.

A search in the Cochrane Database of Systematic Reviews was conducted to further examine dosing regimens for neuropathic pain. In a review analyzing 37 studies for gabapentin treatment in chronic neuropathic pain, the main outcome was Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) definitions for moderate and substantial benefit in chronic pain studies. These were defined as follows:

  • 30% reduction in pain over baseline (moderate)
  • 50% reduction in pain over baseline (substantial)
  • Much or very much improved on Patient Global Impression of Change (PGIC) (moderate)
  • Very much improved on PGIC (substantial)
  • Gabapentin was shown to be better than placebo across all studies for IMMPACT outcomes. The review concentrated on gabapentin doses of 1,200 mg/d or greater and reported that doses at or above this threshold were reasonably effective for treatment of various neuropathic pain types. The upper threshold for maximum effective gabapentin doses ranged from 2,400 mg/d to 3,600 mg/d in the majority of studies reviewed.6 Table 1, on page 16, provides a more detailed description of the maximum gabapentin doses evaluated for different neuropathic pain types.

ADEs and withdrawal rates for patients taking gabapentin doses of 1,200 mg/d or greater were compared to those for patients taking placebo in 20 studies with 4,125 participants. Common ADEs seen were somnolence, drowsiness, and sedation. These occurred in 14% of participants in the gabapentin group versus 5% of those taking placebo. Data also showed gabapentin was associated with a higher incidence of dizziness (19% vs 5%), peripheral edema (7% vs 2.2%), and ataxia or gait disturbances (8.8% vs 1.1%). The rate of serious events was similar between gabapentin and placebo groups. Twenty-two studies involving 4,448 patients reported on participant withdrawals due to ADEs, which occurred in 11% of patients taking gabapentin compared to 7.9% of those taking placebo.

Postmarketing Abuse

Postmarketing reports have described symptoms of agitation, confusion, and disorientation upon abrupt withdrawal of gabapentin. Cases usually involve other potentiating factors, such as the use of higher than recommended doses for unapproved indications, a history of poly-substance abuse, or the use of gabapentin to relieve symptoms of withdrawal from other substances.In a study of postmortem toxicology, cases that tested positive for gabapentin or pregabalin were included to determine if abuse of these drugs contributed to the fatalities. Of the 13,766 cases investigated, 0.31% were positive for gabapentin. Of the gabapentin cases, 18.6% were considered abuse, and 4.7% were poisonings. An overwhelming majority of abuse cases (87.5%) also involved opioid intoxication, and 100% involved alcohol and/or opioids. In addition, a greater number of pregabalin cases were designated as abuse cases than gabapentin cases (48.1% vs 18.6%, respectively).

Conclusion

Gabapentin has sufficient evidence showing its efficacy and safety in treating neuropathic pain. Effective treatment doses of gabapentin for neuropathic pain tend to be higher compared to effective treatment doses for other conditions. Gabapentin is a relatively safe medication. The most prevalent effects seen are drowsiness, somnolence, and sedation. It is necessary to start at lower doses of gabapentin and titrate up to a therapeutic dose. Ataxia and somnolence appear to exhibit a positive dose-response relationship; therefore, titrating the dose of gabapentin may help manage possible ADEs.