Gabapentin is an anticonvulsant medication that helps control seizures in people with epilepsy. Some forms of gabapentin can also treat restless legs syndrome (RLS) and certain types of nerve pain.

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, and liquid form.

This article describes the uses, dosages, and side effects of gabapentin. It also looks into the associated risks and some other safety considerations.

Gabapentin’s primary use is to prevent or control seizures. It works by calming nerve activity to reduce seizure intensity or occurrence.

Children and adults can take this drug. The brand-name drug Neurontin can treat one form of epilepsy in children as young as 3 years old. Some people take other medications with gabapentin to control epilepsy symptoms.

Gabapentin can also help reduce post-herpetic neuralgia, which refers to a burning or stabbing nerve pain that is a common complication of shingles.

According to one 2017 review, oral gabapentin can reduce moderate or severe nerve pain that results from shingles or diabetes at a minimum daily dosage of 1,200 milligrams.

Extended-release gabapentin (Horizant) tablets can treat RLS, which is a condition characterized by uncomfortable sensations in the legs and a strong or irresistible urge to move the lower limbs.

A 2016 study also suggests that gabapentin combined with oxycontin, which is an opioid pain reliever, can help control pain and increase the quality of life for people with severe cancer pain. However, doctors do not typically prescribe gabapentin for this purpose.

Gabapentin can cause mild side effects. According to the 2017 review, these effects were slightly more common in people taking gabapentin than a placebo.

The most common side effects, occurring in around 10% of participants taking gabapentin, were:

  • dizziness
  • sleepiness
  • water retention, which refers to swelling of the arms, hands, legs, and feet
  • difficulty walking

Children and older adults may be more susceptible to adverse reactions associated with gabapentin.

Some other possible side effects include:

In children, some of the more common adverse reactions include:

  • anxiety, depression, or other mood changes
  • behavioral problems
  • changes in performance at school
  • hyperactivity
  • a lack of concentration

Individuals taking gabapentin should talk with a doctor about any problems they experience while doing so, especially if they are severe, ongoing, or getting worse.

People taking gabapentin should be aware of the following serious safety concerns.

Breathing problems

In 2019, the Food and Drug Administration (FDA) issued a warning that people with respiratory risk factors who take the different brands of gabapentin may experience serious breathing difficulties.

People who have conditions such as chronic obstructive pulmonary disease or asthma should speak with a doctor before taking gabapentin.

Risk of suicidal thoughts or behaviors

Studies suggest that some people may experience thoughts of suicide or exhibit suicidal behaviors when taking gabapentin or other anticonvulsants.

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

Risk of overdose

Despite research in this area, it is not always clear whether suicidal behaviors in people who take gabapentin are a result of the drug itself or related to an existing mental health condition.

It is clear, however, that the risk of overdose from the drug is higher if a person also has a mental health condition such as depression.

In addition, when taking gabapentin, a person should monitor themselves carefully to make sure that they are not accidentally taking the wrong dosage.

People should also check on loved ones and minors taking this medication and seek help if there is any concern that they may have suicidal thoughts or behaviors.

Data from U.S. poison centers show that between 2012 and 2017, the number of suspected intentional suicide attempts from a gabapentin overdose grew by 80.5%.

According to the FDA, there have been reports of oral overdoses from taking up to 49 grams of the drug.

Symptoms of an overdose may include:

  • sleepiness
  • lethargy
  • double vision
  • slurred speech
  • diarrhea
  • coma, in cases when someone has chronic renal failure and has received treatment with Neurontin

Interactions with other medications and substances

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

People should be sure to give a doctor a full list of their current medications and supplements before taking gabapentin.

The results of another 2017 review suggest that the following are some of the main substances that interact with the drug:

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

If gabapentin causes sleepiness, a person should speak with a doctor before taking other medications that can also cause drowsiness, including:

  • antianxiety medications
  • antidepressants
  • antihistamines
  • cold and flu medications
  • muscle relaxers
  • narcotics, which are pain medications
  • sleeping pills

Presence of other health conditions

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

Risks during pregnancy and when breastfeeding

People who are pregnant and those who intend to become pregnant should tell a doctor before taking gabapentin.

Research from 2020 suggests that taking this drug during pregnancy may be associated with a higher risk of cardiac malformations in the fetus, a condition called small for gestational age, and preterm birth.

However, it is also essential to control seizures during pregnancy, so pregnant people should only take the drug if it is absolutely necessary.

People should never start or stop taking gabapentin for seizure control before talking with a doctor. They will assess the potential risks and benefits.

After childbirth, gabapentin passes into breast milk. At low levels, it may not affect the infant. However, it is best to discuss this issue with a doctor before breastfeeding.

Potential for allergies

People with gabapentin allergies should not take this drug.

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

It is important to seek emergency medical treatment if symptoms of a severe allergic reaction occur. These may include:

  • breathing difficulties
  • extreme dizziness
  • fever
  • hives
  • rash
  • severe weakness
  • swelling of the face, lips, tongue, or throat
  • yellowing of the skin or eyes, otherwise known as jaundice

People can report adverse drug reactions to the FDA at 800-FDA-1088 or through MedWatch.

Other safety considerations

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

Also, people should 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 of alcohol while taking gabapentin, as there is a risk of adverse reactions.

The right dosage of gabapentin for an individual depends on several factors, including:

  • the type and brand of gabapentin they use
  • the strength of the product
  • the condition they have
  • their kidney function
  • their weight, age, and general health

The number of daily doses, the hours that pass between those doses, and how long a person takes gabapentin will vary among individuals.

A person should take some forms of gabapentin with food, but for other forms, this is not necessary. Anyone who receives a prescription for the Horizant brand of gabapentin for RLS should take it only during the evening or at night.

Some brands and dosages require a person to break the tablets in half. Always use the other half with the next dose or as soon as possible. Never break or chew extended-release gabapentin tablets. People should always swallow these whole.

It is vital to take only the recommended dosage of gabapentin and not to continue using it for longer than a doctor prescribes. If a person misses a dose, they should follow the instructions on the label or call a pharmacist for advice.

What to do if you miss a dose

If a person misses a dose of gabapentin, they should take their required dose as soon as they remember. The only exception is if it is already time to take the next dose. In this case, the person should simply skip the missed dose and take the next dose at the usual time.

A person should never take two doses of gabapentin together.

Doctors prescribe gabapentin to control seizures, treat RLS, and reduce nerve pain. Several types of gabapentin are available, and different forms can treat different medical issues.

The right dosage will vary depending on the condition a person has and several other factors. A doctor can best advise about drug interactions and other safety considerations.

Although gabapentin can cause several adverse reactions, many people experience no serious side effects from this drug.