When Was Gabapentin Approved by the U.S. Food and Drug Administration (FDA) ?

About Gabapentin

There are many drugs used to treat anxiety. New studies are now showing that Gabapentin has been a successful treatment for individuals who suffer from anxiety. However, there are no randomized controlled trials on the effectiveness of this medication in generalized anxiety disorder (GAD), and there are only a few case reports.

People with GAD who take Gabapentin have shown to be less irritable, reduce the use of alcohol as self-medication, have fewer depression symptoms, feel less anxious anticipating the future, improve in phobic avoidance (going out in public more and experiencing a significant decrease in panic disorder and reduction of panic attacks).

Gabapentin is an anticonvulsant drug that is primarily used to treat seizures and the pain that follows after an episode of shingles. Gabapentin is considered an off-brand drug used to treat anxiety. Neurontin is the most common brand name for Gabapentin, as well as Horizant and Gralise. Gabapentin has shown to help people with sleeping better, as insomnia is a symptom of anxiety.

Side Effects of Gabapentin 

Like all medications, there are several side effects to taking Gabapentin. Side effects that you experience are relative to your personal reaction to the drug. Everyone is different, so you may not experience side effects that others do or don’t. Some side effects can be nausea, vomiting, tremors, dizziness, sleepiness, double vision, loss of control of bodily movements, fluid retention, difficulty speaking, jerky movements, unusual eye movements, double vision, and unsteadiness.

If you begin to experience any of these symptoms, speak with your doctor immediately. Get emergency help if you suspect you are having an allergic reaction like; swelling of your face, lips, tongue, or throat, hives, and difficulty breathing. If you notice that your symptoms are worsening, contact your doctor immediately. You may not notice symptoms until weeks after taking Gabapentin.

Is Gabapentin Approved by the U.S. Food and Drug Administration (FDA) ?

Gabapentin was originally approved by the U.S. Food and Drug Administration (FDA) in December 1993, for use as an adjuvant medication to control partial seizures (effective when added to other antiseizure drugs) in adults; that indication was extended to children in 2000. In 2004, its use for treating postherpetic neuralgia (neuropathic pain following shingles) was approved.

Gabapentin is best known under the brand name Neurontin manufactured by Pfizer subsidiary Parke-Davis. A Pfizer subsidiary named Greenstone markets generic gabapentin.

In December 2004 the FDA granted final approval to a generic equivalent to Neurontin made by the Israeli firm Teva.

Neurontin began as one of Pfizer’s best selling drugs; however, Pfizer has come under heavy criticism and serious litigation for its marketing of the drug.

They face allegations that, behind the scenes, Parke-Davis marketed the drug for at least a dozen supposed uses that the FDA had not approved.

Today it is a mainstay drug for migraines, even though it was not approved for such use in 2004.

What is Gabapentin Used for ?

Gabapentin comes as a capsule, a tablet, an extended-release (long-acting) tablet, and an oral solution (liquid) to take by mouth. Gabapentin capsules, tablets, and oral solution are usually taken with a full glass of water (8 ounces [240 milliliters]), with or without food, three times a day.

These medications should be taken at evenly spaced times throughout the day and night; no more than 12 hours should pass between doses. The extended-release tablet (Horizant) is taken with food once daily at about 5 PM. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take gabapentin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Gabapentin extended-release tablets cannot be substituted for another type of gabapentin product. Be sure that you receive only the type of gabapentin that was prescribed by your doctor. Ask your pharmacist if you have any questions about the type of gabapentin you were given.

Swallow the extended-release tablets whole; do not cut, chew, or crush them.

If your doctor tells you to take one-half of a regular tablet as part of your dose, carefully split the tablet along the score mark. Use the other half-tablet as part of your next dose. Properly dispose of any half-tablets that you have not used within several days of breaking them.

If you are taking gabapentin to control seizures or PHN, your doctor will probably start you on a low dose of gabapentin and gradually increase your dose as needed to treat your condition. If you are taking gabapentin to treat PHN, tell your doctor if your symptoms do not improve during your treatment.

Gabapentin may help to control your condition but will not cure it. Continue to take gabapentin even if you feel well. Do not stop taking gabapentin without talking to your doctor, even if you experience side effects such as unusual changes in behavior or mood. If you suddenly stop taking gabapentin tablets, capsules, or oral solution, you may experience withdrawal symptoms such as anxiety, difficulty falling asleep or staying asleep, nausea, pain, and sweating. If you are taking gabapentin to treat seizures and you suddenly stop taking the medication, you may experience seizures more often. Your doctor may decrease your dose gradually over at least a week.

Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with gabapentin and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs) or the manufacturer’s website to obtain the Medication Guide.

Off-label use exposes patients to adverse effects and generally is not supported by evidence.

The only conditions for which gabapentinoid drugs are FDA-approved to manage pain are postherpetic neuralgia (both gabapentin and pregabalin [Lyrica]) and diabetic neuropathy, spinal cord injury, and fibromyalgia (pregabalin only). Nevertheless, use of these drugs has tripled during the past 15 years. This increase likely reflects gabapentinoid use for managing non–FDA-approved pain conditions, in part to avoid opioid use. In this review, researchers identified 34 placebo-controlled randomized trials (with ≈4200 patients) of gabapentinoids for noncancer, non–FDA-approved pain conditions. Most trials’ durations were 4 to 12 weeks.

Results of the review were as follows:

  • Only weak evidence supports use of gabapentin for diabetic neuropathy (only pregabalin is approved for this indication).
  • Minimal evidence supports use of gabapentin for nondiabetic painful neuropathies.
  • Studies of gabapentinoids for managing low back pain or sciatica have been largely negative.
  • Only minimal evidence supports a clinically meaningful benefit of off-label gabapentin use for fibromyalgia (for which pregabalin is approved).
  • Both gabapentin and pregabalin are approved for managing postherpetic neuralgia, but both are used often for acute zoster pain, for which studies have shown no benefit.
  • A small number of studies of gabapentinoid use for other pain syndromes (e.g., traumatic nerve injury, complex regional pain syndrome, burn injury, sickle cell pain) showed no clinically important benefits.

COMMENT

The markedly increased off-label use of gabapentinoids to manage pain has no or limited evidence of benefit. This practice is worrisome, especially given known high rates of side effects, including dizziness, somnolence, and unsteadiness. In addition, the authors note that patients often are prescribed gabapentinoids to avoid opioid use, but such patients sometimes still use opioids, either prescribed or illicit. The combination of gabapentinoids and opioids is associated with excess risk for opioid overdose.

Dr. Brett is an author of this article and is the Editor-in-Chief of NEJM Journal Watch General Medicine; however, he had no role in selecting or summarizing this article.

What Happens if You suddenly Stop Gabapentin?

About Gabapentin

There are many drugs used to treat anxiety. New studies are now showing that Gabapentin has been a successful treatment for individuals who suffer from anxiety. However, there are no randomized controlled trials on the effectiveness of this medication in generalized anxiety disorder (GAD), and there are only a few case reports.

People with GAD who take Gabapentin have shown to be less irritable, reduce the use of alcohol as self-medication, have fewer depression symptoms, feel less anxious anticipating the future, improve in phobic avoidance (going out in public more and experiencing a significant decrease in panic disorder and reduction of panic attacks).

Gabapentin is an anticonvulsant drug that is primarily used to treat seizures and the pain that follows after an episode of shingles. Gabapentin is considered an off-brand drug used to treat anxiety. Neurontin is the most common brand name for Gabapentin, as well as Horizant and Gralise. Gabapentin has shown to help people with sleeping better, as insomnia is a symptom of anxiety.

Treatment with Gabapentin: Important Things to Know Before Taking Gabapentin

Before you start gabapentin therapy, you should have a thorough medical exam to rule out any medical issues. This includes any blood or urine tests. Medical evaluations are important as gabapentin can induce hormonal imbalances. Like any other drug, you should not take gabapentin if you’re allergic to it.

There are side effects—more on that in a minute. But a few of the most important things your doctor will want to find out before prescribing gabapentin is if you have or have had any of the following:

  • Diabetes
  • Drug or alcohol addiction
  • Kidney problems (or if you’re on dialysis)
  • Liver or heart disease
  • Lung disease (see the warning above on respiratory issues)
  • Mood disorders, depression or bipolar; or if you’ve ever thought about suicide or attempted suicide
  • Seizures (unless, of course, you’re taking it for seizures)

You should also know that not enough studies have been done to understand the exact risks of gabapentin if you’re pregnant or breastfeeding.

Side Effects of Gabapentin 

Like all medications, there are several side effects to taking Gabapentin. Side effects that you experience are relative to your personal reaction to the drug. Everyone is different, so you may not experience side effects that others do or don’t. Some side effects can be nausea, vomiting, tremors, dizziness, sleepiness, double vision, loss of control of bodily movements, fluid retention, difficulty speaking, jerky movements, unusual eye movements, double vision, and unsteadiness.

If you begin to experience any of these symptoms, speak with your doctor immediately. Get emergency help if you suspect you are having an allergic reaction like; swelling of your face, lips, tongue, or throat, hives, and difficulty breathing. If you notice that your symptoms are worsening, contact your doctor immediately. You may not notice symptoms until weeks after taking Gabapentin.

What happens if you suddenly stop gabapentin?

It’s important to discuss your concerns about gabapentin first with your doctor or pharmacist before you stop the medication.

You might have certain symptoms if you suddenly stop gabapentin:

  • withdrawal symptoms such as agitation, restlessness, anxiety, insomnia, nausea, sweating, or flu-like symptoms. The risks of withdrawal are higher if you’re taking high doses or have been on gabapentin for longer than 6 weeks. Withdrawal symptoms can start from 12 hours to 7 days after stopping the medication.
  • status epilepticus, which is a rapid cycle of seizure activity so that an individual experiences an almost constant seizure for a period of time
  • irregular heart rate
  • confusion
  • headache
  • tiredness
  • weakness
  • return of nerve pain

 

Safety and Risks of Taking Gabapentin

Gabapentin appears to work by altering electrical activity in the brain and influencing the activity of chemicals called neurotransmitters, which send messages between nerve cells. Brand names for gabapentin include Horizant, Gralise, and Neurontin. The medication is available in capsule, tablet, or liquid form.

In this article, we describe the uses, dosages, and side effects of gabapentin. We also look into the associated risks and other safety considerations.

People taking gabapentin should be aware of the following:

Risk of suicidal thoughts or behaviors

Some people experience thoughts of suicide or exhibit suicidal behavior when taking gabapentin or other anticonvulsants.

If a person or their loved one notices changes in mood or behavior, they should contact a doctor immediately.

Interactions with other medications and substances

Gabapentin can interact with other prescription or over-the-counter medications, vitamins, and herbal supplements.

Be sure to give the doctor a full list of current medications and supplements before taking gabapentin.

Results of a 2017 review suggest that the following are the main substances that interact with the drug:

  • caffeine, which is present in tea, coffee, and cola
  • ethacrynic acid, a diuretic
  • losartan, a medication for high blood pressure
  • magnesium oxide, a mineral supplement and antacid
  • mefloquine, an antimalarial drug
  • morphine, an opioid pain medication
  • phenytoin, an anti-seizure medication

If gabapentin causes sleepiness, speak to the doctor before taking other medications that can also cause drowsiness, including:

  • antianxiety medications
  • antidepressants
  • antihistamines
  • cold and flu medications
  • muscle relaxers
  • narcotics (pain medications)
  • sleeping pills

Presence of other health conditions

To ensure that gabapentin is safe to take, a person should tell their doctor if they currently have or have ever experienced:

  • breathing problems
  • depression or other mental health disorders
  • diabetes
  • dialysis treatment
  • drug and alcohol misuse issues
  • heart disease
  • kidney disease
  • liver disease
  • seizures (if taking gabapentin for conditions unrelated to seizures)

Risks during pregnancy and when breastfeeding

People who are pregnant, or intend to become pregnant, should tell their doctor before taking gabapentin.

Pregnant women should only take the drug if it is absolutely necessary. However, it is also essential to control seizures while pregnant.

Do not start or stop taking gabapentin for seizure control before talking to the doctor, who will assess the potential risks and benefits.

Gabapentin passes into breast milk, but its effects on babies are unknown. It is best to discuss this issue with a doctor before breastfeeding.

Potential for a drug allergy

Individuals with gabapentin allergies should not take the drug.

Also, the medication may contain other ingredients that can trigger allergy symptoms in some people. Discuss all drug and food allergies with a doctor before taking gabapentin.

Other safety considerations

Because gabapentin can cause drowsiness, anyone taking the drug should exercise caution while driving or using machinery.

Do not take antacids within 2 hours of taking gabapentin, as antacids reduce the body’s ability to absorb the drug.

People should also avoid alcohol or limit their intake while on gabapentin because there is a risk of adverse reactions.

How Gabapentin is Used ?

Gabapentin comes as a capsule, a tablet, an extended-release (long-acting) tablet, and an oral solution (liquid) to take by mouth.

Gabapentin is usually started at a low dose and then gradually increased. Be sure to follow your doctor’s instructions. A typical dose ranges between 900 mg and 1,800 mg daily, divided into three doses. You shouldn’t stop taking gabapentin suddenly. Be sure to talk to your doctor about the proper weaning procedure for the dose you’re taking.

Gabapentin capsules, tablets, and oral solution are usually taken with a full glass of water (8 ounces [240 milliliters]), with or without food, three times a day.

These medications should be taken at evenly spaced times throughout the day and night; no more than 12 hours should pass between doses. The extended-release tablet (Horizant) is taken with food once daily at about 5 PM. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take gabapentin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Gabapentin extended-release tablets cannot be substituted for another type of gabapentin product. Be sure that you receive only the type of gabapentin that was prescribed by your doctor. Ask your pharmacist if you have any questions about the type of gabapentin you were given.

How Gabapentin Works

Gabapentin is believed to work by altering the release of glutamate and other neurotransmitters in your brain.1 Neurotransmitters send messages from one brain cell to another. Glutamate is really helpful for certain things, like learning new information. That’s because it gets your brain cells stirred up and active.

Kind of like a toddler with chocolate, though, if you have too much glutamate running around, your brain cells can become overstimulated. That can make all kinds of things go wrong.

Glutamate has more than one job, though. It also helps transmit pain signals in your brain and nerves. Too much glutamate may play a role in hyperalgesia, which essentially turns up the volume of pain.

Some diseases and conditions—including fibromyalgia—may interrupt this balance and let glutamate run amok. Gabapentin is believed to reduce your brain’s release of glutamate so the cells can calm down and your brain can function better.

Swallow the extended-release tablets whole; do not cut, chew, or crush them.

If your doctor tells you to take one-half of a regular tablet as part of your dose, carefully split the tablet along the score mark. Use the other half-tablet as part of your next dose. Properly dispose of any half-tablets that you have not used within several days of breaking them.

How Gabapentin is Used ?

If you are taking gabapentin to control seizures or PHN, your doctor will probably start you on a low dose of gabapentin and gradually increase your dose as needed to treat your condition. If you are taking gabapentin to treat PHN, tell your doctor if your symptoms do not improve during your treatment.

Gabapentin may help to control your condition but will not cure it. Continue to take gabapentin even if you feel well. Do not stop taking gabapentin without talking to your doctor, even if you experience side effects such as unusual changes in behavior or mood.

If you suddenly stop taking gabapentin tablets, capsules, or oral solution, you may experience withdrawal symptoms such as anxiety, difficulty falling asleep or staying asleep, nausea, pain, and sweating.

If you are taking gabapentin to treat seizures and you suddenly stop taking the medication, you may experience seizures more often. Your doctor may decrease your dose gradually over at least a week.

Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with gabapentin and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs) or the manufacturer’s website to obtain the Medication Guide.

Gabapentin is somewhat commonly prescribed as a fibromyalgia treatment. It’s available as a generic and is also sold under the brand names Neurontin, Horizant, and Gralise.

Gabapentin is not FDA approved for treating this condition, so it’s prescribed off-label. However, the drug is chemically related to Lyrica (pregabalin), which is approved for fibromyalgia. In fact, Lyrica is sometimes referred to as the “son of Neurontin.”

Gabapentin is classified as an anti-seizure drug. It’s used to treat epilepsy, neuropathy (pain from damaged nerves), restless legs syndrome, and hot flashes. Fibromyalgia pain is similar to neuropathy, but whether this condition involves nerve damage still isn’t clear.