Specifically, the Food and Drug Administration (FDA) has approved gabapentin oral forms to treat:
- nerve pain caused by shingles in adults
- focal onset seizures (also known as partial seizures) caused by epilepsy in adults and some children, taken together with other seizure medications
This article describes possible side effects of gabapentin oral capsules, tablets, and solution. You’ll also find information on cost savings and coupon options for gabapentin.
Gabapentin oral forms are generic versions of the brand-name drugs Neurontin and Gralise. Gabapentin also comes in additional forms taken by mouth, but only the oral forms mentioned above are described in this article. To learn more about the additional forms, talk with your doctor.
You can explore this overview article to learn more about gabapentin oral forms, including the drug’s uses, dosage, and more.
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More common side effects of gabapentin
Gabapentin oral forms may cause mild or serious side effects. Below are some of the more common side effects of this medication. These side effects occurred during studies of gabapentin’s oral capsule, oral tablet, and oral solution. They also varied slightly based on the condition they were used to treat.
More common side effects in people taking gabapentin oral forms for nerve pain after shingles include:
- dizziness
- sleepiness
- swelling in the hands or feet
More common side effects in people taking gabapentin oral forms for epilepsy include:
- dizziness
- sleepiness
- ataxia (problems with muscle coordination and control)
- fatigue
Mild side effects of gabapentin
Gabapentin may cause certain mild side effects. Most often, mild side effects are temporary and can be managed easily. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.
Mild side effects that occurred in studies of gabapentin’s oral capsule, oral tablet, and oral solution include:
- dizziness
- sleepiness
- swelling in the hands or feet
- ataxia (problems with muscle coordination and control)
- fatigue
- infection, such as a viral infection
- nausea and vomiting
- diarrhea
- dry mouth
- weakness
- trouble speaking
- double or blurry vision
- nystagmus (involuntary eye movements)
- weight gain
- constipation
- mild allergic reaction*†
* To learn more about this side effect, see the “Side effects of gabapentin in detail” section below.
† A mild allergic reaction is possible with gabapentin oral forms. But it wasn’t reported in studies of the drug’s oral capsule, oral tablet, and oral solution.
Gabapentin oral forms may cause more mild side effects than those listed above. For details, see the prescribing information for gabapentin’s oral capsule, oral tablet, and oral solution.
Serious side effects of gabapentin
Gabapentin may cause certain serious side effects. If you have any serious side effects from gabapentin, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911 or a local emergency number, or go to the nearest emergency room.
After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Visit the MedWatch website if you’d like to notify the FDA about a side effect you’ve had with gabapentin.
Serious side effects that occurred in studies of gabapentin’s oral capsule, oral tablet, and oral solution include:
* To learn more about this side effect, see the “Side effects of gabapentin in detail” section below.
† A severe allergic reaction is possible with gabapentin oral forms. But it’s unclear whether it occurred in studies of the drug’s oral capsule, oral tablet, and oral solution.
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Side effects of gabapentin in children
Gabapentin is prescribed to treat partial onset seizures caused by epilepsy in children ages 3 years and older. For this use, it’s prescribed together with other seizure medications.
In studies of gabapentin, side effects in children ages 12 years and older were similar to those described above for adults. (For details, see the prescribing information for the oral capsule, oral tablet, and oral solution.) But in children ages 3 years through 11 years, additional side effects included:
- fever
- hostility and aggression
- restlessness or hyperactivity
- behavioral problems
- concentration problems
In most instances, these side effects were considered mild or moderate in severity.
Talk with your child’s doctor if you have questions or concerns about side effects of gabapentin.
Common questions about side effects of gabapentin
Here are answers to some commonly asked questions about side effects of gabapentin oral forms. If you have other questions, talk with your doctor or pharmacist.
Does gabapentin cause different side effects in women versus men?
It might, but studies showed similar side effects in females* and males.* For details about studies, see the prescribing information for gabapentin’s oral capsule, oral tablet, and oral solution.
But since the time gabapentin was approved, some sexual side effects have been reported in people taking it. It’s not known whether gabapentin or other factors caused these side effects, since they happened outside of gabapentin studies. These sexual side effects could be different for females and males. Examples include:
Talk with your doctor if you have concerns about sexual side effects and gabapentin.
* Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.
How do the side effects of gabapentin in older adults compare with those seen in younger adults?
Gabapentin’s side effects in older adults are mostly the same as in younger adults. (Older adults are usually considered ages 65 years and older.)
But adults in this age group were more likely to have certain side effects. This was noted in studies of gabapentin’s oral capsule, oral tablet, and oral solution. These side effects include swelling in the hands or feet and ataxia. (Ataxia is problems with muscle coordination and control.)
In addition, older adults are more likely to have kidney problems. Having kidney problems increases the risk of side effects from gabapentin. If you have kidney problems, your doctor may adjust your dose.
Ask your doctor whether your age affects your risk of side effects from gabapentin.
Is weight gain or headache a possible side effect of gabapentin?
Weight gain is a side effect reported in gabapentin studies.
On the other hand, headache was reported rarely in children ages 3 years through 11 years. But children who took a placebo (pill with no active drug) also reported headache as a side effect.
These results for weight gain and headache were noted in studies of gabapentin’s oral capsule, oral tablet, and oral solution.
Talk with your doctor if you’re concerned about these side effects from gabapentin.
Can gabapentin be used in dogs? If so, what side effects can it cause in dogs?
Gabapentin is not FDA-approved for use in dogs, but veterinarians might prescribe it off-label for dogs. (With off-label use, doctors prescribe a drug for a purpose other than what it’s approved for.)
It’s possible for dogs to have side effects from gabapentin, such as poor balance, trouble walking, and lethargy (lack of energy). Nausea and vomiting are also possible but less common side effects.
Higher doses of gabapentin in dogs are more likely to cause side effects. But when given in prescribed doses, serious side effects are unlikely.
You should only give medications to your dog if they’re prescribed by a veterinarian. And be sure to follow the prescribed dosage.
Can gabapentin be used in cats? If so, what side effects do cats experience?
Veterinarians may prescribe gabapentin off-label for cats. Among other uses, the drug may be prescribed to help reduce pain or ease stress and anxiety during procedures.
Possible side effects of gabapentin in cats include sleepiness, poor balance, and trouble walking.
As with all animals, consult a qualified veterinarian before giving any medication to your cat or other pet. They can discuss the right medication and dosage for your pet, as well as possible side effects.
Does gabapentin cause long-term side effects?
It’s possible for gabapentin to cause long-term side effects.
Long-term side effects refer to those that:
- occur at any point during treatment, even if you’ve taken the drug for a long time without having the side effect
- occur or continue even after you stop taking the drug
According to studies of gabapentin’s oral capsule, oral tablet, and oral solution, long-term side effects might include:
Talk with your doctor if you have questions or concerns about long-term side effects with gabapentin.
* To learn more about this side effect, see the “Side effects of gabapentin in detail” section below.
Withdrawal, dependence, misuse, and gabapentin
Below is information on withdrawal and misuse concerning gabapentin.
Gabapentin and withdrawal symptoms
Withdrawal symptoms were reported in studies of gabapentin’s oral capsule, oral tablet, and oral solution, but rarely. These are side effects that can occur when you stop taking a drug on which your body has become dependent. (With dependence, your body needs the drug to function like usual.) Examples of withdrawal symptoms reported in studies include:
Also, suddenly stopping a seizure drug, such as gabapentin, can cause seizures more frequently than usual. For this reason, do not abruptly stop your seizure medication, including gabapentin. Instead, talk with your doctor if you’re considering stopping treatment. They can lower your dose slowly over time to reduce the risk of more frequent seizures from stopping treatment.
Withdrawal symptoms have been reported in rare cases since gabapentin became approved for use. (See the prescribing information for the oral capsule, oral tablet, and oral solution for details.) These reports occurred in people taking the drug off-label at doses higher than the approved doses. With off-label drug use, doctors prescribe a drug for a purpose other than its approved use.
Gabapentin and misuse
Since the time gabapentin was approved for use, there have been rare reports of drug misuse. (See the prescribing information for the oral capsule, oral tablet, and oral solution for details.) With misuse, a drug is used in a manner other than how it’s prescribed. As an example, taking gabapentin in an attempt to get “high” is a misuse of the drug.
Due to this risk, your doctor will ask about your health history before prescribing gabapentin. Specifically, they’ll need to know whether you have a history of substance use disorder or misuse.
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Side effects of gabapentin in detail
Below you’ll find details on some of the side effects of gabapentin oral forms.
Increased risk of suicidal thoughts and behaviors
Seizure drugs increase the risk of suicidal thoughts and behaviors. This includes gabapentin. The risk applies whether you’re taking gabapentin to treat seizures or another condition.
Actual reports of suicidal thoughts or behaviors are rare, according to studies of gabapentin’s oral capsule, oral tablet, and oral solution.
Ways to manage
During treatment with gabapentin, watch closely for any changes in your behaviors and thoughts. If you’re comfortable doing so, it’s helpful to tell close friends or loved ones that you’re taking this medication. And be sure to let them know about this risk as well. They can help watch for any changes in your behaviors or mood.
If you notice any changes, call your doctor immediately or seek emergency medical attention right away.
Suicide prevention
If you or someone you know is in crisis and considering suicide or self-harm, please seek support:
If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.
If you are not in the same household, stay on the phone with them until help arrives.
A serious reaction called DRESS syndrome
Rarely, taking gabapentin can cause drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome. This is a serious, life threatening condition that affects multiple organs.
DRESS syndrome is a rare type of drug allergy. It may not cause symptoms until after you’ve taken gabapentin for several weeks.
Symptoms of DRESS can include:
- fever
- skin rash
- swollen lymph nodes
- inflammation in your internal organs
- abnormal blood count
Ways to manage
DRESS syndrome is life threatening and requires immediate medical treatment. Recognizing the symptoms early and treating DRESS promptly are important to prevent long-term issues or possibly death. If you develop DRESS syndrome from taking gabapentin, your doctor will stop your treatment.
Allergic reaction
For some people, gabapentin oral forms can cause an allergic reaction. Mild allergic reaction wasn’t reported in studies of the oral capsule, oral tablet, and oral solution. It’s unclear whether severe allergic reaction (anaphylaxis) occurred in the drug’s same studies.
Symptoms can be mild or serious, and they may include:
- itchiness
- skin rash
- swelling under the skin, usually affecting eyelids, lips, hands, or feet
- swelling of the mouth, tongue, or throat, which can make it hard to breathe
- flushing (temporary warmth, redness, or deepening of skin color)
A rare and severe form of allergic reaction called DRESS syndrome is also possible, and it’s described just above.
Ways to manage
For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know if you should keep taking the medication.
For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or a local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to gabapentin oral forms, your doctor may recommend taking a different medication instead.
Warnings for gabapentin
Below are some factors you may want to discuss with your doctor before taking gabapentin oral forms.
Warnings
It may not be safe for you to take gabapentin oral forms if you have specific health conditions. These are sometimes called drug-condition interactions. Other things may also affect whether gabapentin oral forms are a safe treatment option for you.
Before taking gabapentin oral forms, tell your doctor about your health and medications you take. Things to consider include those listed below.
Breathing or lung problems. Rarely, gabapentin can cause dangerously slow, shallow breathing as a side effect. This is called respiratory depression. Having a breathing or lung problem places you at higher risk of this side effect. If you have a breathing problem, such as asthma, ask your doctor whether gabapentin is safe for you.
Depression, mood disorder, or suicidal thoughts or behaviors. Treatment with gabapentin increases the risk of suicidal thoughts and behaviors. You may be at higher risk if you have depression or a mood disorder. Your risk also may be higher if you have or have had suicidal thoughts or behaviors.
Before you start taking gabapentin, let your doctor know of any mental health conditions you have. They can determine whether the drug is safe for you to take.
Kidney problems. Having a kidney problem can cause gabapentin to build up in your body. This increases your risk of side effects that the drug may cause, such as central nervous system (CNS) depression.
Before you start gabapentin, your doctor will discuss kidney problems you might have, including receiving dialysis. If you have any, your doctor will likely prescribe a lower gabapentin dose.
Allergic reaction. If you’ve had an allergic reaction to gabapentin oral forms or any of the ingredients, your doctor will likely not prescribe this medication. Ask them about other treatment options that may be better for you.
Gabapentin and pregnancy
It’s not known whether it’s safe to take gabapentin during pregnancy. There isn’t enough information from studies that include pregnant people. Talk with your doctor about the benefits and risks of taking gabapentin if you’re pregnant or can become pregnant.
If you and your doctor agree you’ll take gabapentin during pregnancy, consider joining the antiepileptic drug pregnancy registry. (Gabapentin is a type of antiepileptic drug, which is a seizure drug.) Pregnancy registries gather information about pregnant people who take the drug. This helps doctors and patients make choices about treatments during pregnancy. Learn more or sign up for the registry by visiting the registry website or calling 888-233-2334.
Gabapentin and breastfeeding
Gabapentin can pass into breast milk. But it isn’t known what effects, if any, this causes on human milk production. It’s also not known whether this can cause side effects in a child who’s breastfed.
Talk with your doctor to discuss the risks and benefits of breastfeeding during gabapentin treatment.
Gabapentin and alcohol
Gabapentin oral forms are known to interact with alcohol.
Both alcohol and gabapentin can cause central nervous system (CNS) depression. This means they each slow the function of the CNS, which includes the brain and spinal cord. So, combining the two increases your risk of side effects, including dizziness and drowsiness.
If you’d like to drink alcohol during treatment with gabapentin oral forms, talk with your doctor. They can advise whether it’s safe for you to do so.
What to ask your doctor
This article describes common and serious side effects of gabapentin oral forms. If your doctor prescribes this medication, they can discuss possible side effects with you. Let your doctor know if you have concerns or questions about treatment with this medication.
Here’s a list of some possible questions you may want to ask your doctor:
- Is gabapentin taken to treat numbness in feet? If so, can it cause certain side effects when taken for this condition?
- Can taking gabapentin affect my blood pressure as a side effect?
- If I have constipation from taking gabapentin, what are safe ways to treat this side effect?
- Does gabapentin cause urinary side effects, such as urinating more often?
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
