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Gabapentin Side Effects: Short and Long-Term Dangers of Use

Last Updated: March 21, 2024

Authored by Olivier George, Ph.D.

Reviewed by Michael Espelin APRN

Neurontin is an anticonvulsant prescription medicine. It’s used to treat epilepsy and is used to treat nerve pain, such as in conditions like shingles. However, it is sometimes a drug of abuse. Like many drugs, however, even in therapeutic use, it has various potential side effects. Some of them can be severe.

However, one may be curious to know, are gabapentin side effects truly that extensive in number? The common adverse effects, and the symptoms in men, women, and children, will be discussed.

What Are the Most Common Side Effects of Gabapentin?

Neurontin’s generic name is gabapentin. All drugs can have potential undesired effects; this one is no different in this regard. These adverse reactions can range from mild like fatigue and drowsiness, to severe, such as seizures and facial swelling. Knowing the range of adverse reactions it may have is important to know when to contact a doctor. Gabapentin side effects can also arise when interacting with other drugs. The following are the most common adverse effects that can be seen with its usage:

  • Drowsiness
  • Dizziness
  • Fatigue
  • Loss of coordination of muscles (ataxia)
  • Involuntary eye movements (nystagmus)
  • Fever
  • Swelling of the limbs (peripheral edema)
  • Nausea
  • Vomiting
  • Viral infection
  • Hostility

Other signs elicited by this medicine include:

  • Headache
  • Tremors
  • Double/blurred vision
  • Anxiety
  • Diarrhea
  • Constipation
  • Increased appetite
  • Weight gain
  • Memory problems
  • Changes in sexual function
  • Dry mouth (xerostomia)
  • Rash
  • Itching (pruritus)
  • Facial swelling
  • Vocal hoarseness
  • Seizures
  • Difficulty breathing (dyspnea)
  • Difficulty swallowing (dysphagia)
  • Suicidal thoughts and behavior


Gabapentin Side Effects

What Are the Short-Term Adverse Effects?

Of the clinical features that may appear following this drug’s administration, many are more short-term in the time at which they appear. Following the dosage and administration regimen dictated by the doctor or pharmacist who prescribed the medication is integral to keep short-term side effects to the minimum. Some of these short-term gabapentin side effects may impair work or school, so using them at night is recommended.

The following are some of the short-term symptoms that may be experienced from using it:

  • Dizziness & Drowsiness – These features are present mostly at the initial stages of using the drug. Due to this, the operation of heavy machinery and any other work where poor concentration may result in damage to life and property should be avoided.
  • Ataxia – This is a lack of coordination and control of voluntary muscles in the body. This makes it hard to move smoothly, which can result in bumping into objects, and potential falls.
  • Memory Loss – Even on low doses, this medicine may affect one’s cognitive abilities, triggering memory loss, and confusion.
  • Difficulty Speaking – The loss of voluntary muscle coordination can affect speech, in addition to the hypersalivation or xerostomia that may arise.
  • Viral Infection – In younger patients who take it to treat epilepsy, they may be predisposed to viral infections.
  • Tremors – Its action on the nervous system may sometimes cause the adverse effect of tremors and jerky motions.
  • Double Vision & Unusual Eye Movements – Some users report doubled or blurred vision, even at low doses. This affects the ability to read. This can be particularly dangerous if the person is driving or operating heavy machinery and doing any tasks that require precision.
  • Fever –  In younger and older patients who may contract viral illnesses, there may be a fever.

What Are Long Term Side Effects of Gabapentin?

The long term side effects of gabapentin tend to be rather difficult, and they should always be taken seriously.

Changes in Behaviour and Mood

Its action on the nervous system can induce some unusual changes in the emotional and psychological state of the person, such as:

  • Depression
  • Anxiety
  • Suicidal thoughts
  • Irritability
  • Aggression

Allergic Reactions

Also known as anaphylaxis, can cause severe, potentially fatal, allergic reactions on rare occasions. This requires immediate attention by a doctor and can be spotted by the following features:

  • Skin rashes
  • Hives
  • Swollen face, lips, tongue, or eyelids
  • Tightness in the throat or chest
  • Difficulty breathing

Status Epilepticus

This is a condition whereby patients with epilepsy can have seizures occur for more than 30 minutes straight. This is a medical emergency and can occur if an epileptic patient stops using the drug suddenly. The medicine should never be stopped without a doctor’s knowledge.

What Are Gabapentin Side Effects in Men?

This includes a reduction in libido, anorgasmia, and impotence. Anorgasmia, in particular, and its relationship to medicine, have been studied well. It is more likely to cause this side effect in older men, manifesting in 3 of 11 men above 50 years of age in a study. However, when drug dosage is reduced or stopped by a doctor, anorgasmia resolves.

What Are the Side Effects of Gabapentin in Women?

In women, the main action of Neurontin on sexual function is somewhat inverse to that of men. It’s found to improve sexual function in women with vulvodynia, a chronic pain condition in the vulva.

 Crying woman with wide-open eyes and covered mouth with hands.

Neurontin improves sexual function mostly regarding arousal, though also with statistically significant increases in desire and satisfaction. Regarding the other domains of sexual function, being lubrication and orgasm, there was no statistically significant change.

A study done reported anorgasmia as one of the side effects of gabapentin in a 59-year old woman. A pair of similar case studies gave information that showed similar anorgasmia in a 41-year old woman and a 28-year old woman. However, suspicions that this symptom was dose-dependent were confirmed as orgasms represented following the doctor’s cessation of the drug.

The Effects During Pregnancy and Breastfeeding

The Food and Drug Administration classifies gabapentin as a category C drug as regards pregnancy. This means that care should be taken with the prescription of the drug in pregnancy, particularly only if the benefits outweigh the risks.

There is relatively little information on the effects of gabapentin on the fetus during pregnancy and the levels of the medication in breast milk. However, the information available does not predispose to an increased risk of neonatal malformations. There is an increased rate of preterm births and low birth weight neonates among women who used it during pregnancy.  In cases where the mother requires it for conditions such as epilepsy or nerve pain, the benefits are weighed against the doctor’s risks to decide upon the next line of action. There has been one case study on gabapentin withdrawal in a neonate following birth, however.

Regarding the presence of the drug in breast milk, one study found that it was present in the breast milk. The levels of this medication in the infants’ blood were compared to that of the mother, being only 12% of the mother’s levels. The drug lasts for five to seven hours in the blood and can be detected on the gabapentin drug test. No gabapentin side effects were noted in the six infants who were subject to this study.

Regardless of this information, women using the drug should always consult with their doctor when pregnant or lactating.

What Are the Adverse Effects on Children?

Neurontin can be used in children, but its use is not allowed in children under the age of 3. The drug is commonly used in children with epilepsy. The common side effects of Neurontin differ slightly from those in adults. If severe, these will require attention from a doctor. Common side effects in children include the following:

  • Drowsiness
  • Nausea
  • Vomiting
  • Fever
  • Weight gain
  • Dizziness

Behavioral Changes

One adverse effect that is more specific to children is the development of significant behavioral changes. These include some of the following:

  • Oppositional behavior
  • Temper tantrums
  • Aggression
  • Hyperactivity
  • Irritability

Gabapentin Warnings

It has been found that there is a chance of serious difficulties in breathing occurring in patients who take this drug, according to information from the United States Food and Drug Administration. This is important to note in patients who may have pre-existing respiratory system conditions, such as asthma.

A guy with a headache sits, and a girl behind him.

The chance for unexpected gabapentin symptoms such as this is increased when it is combined with other drugs, such as opioids, anxiolytics, or antidepressants. Moreover, in combination with other drugs, the possibility of overdose on gabapentin is very high.

Who Is at Greater Risk of Adverse Reactions?

While Neurontin’s common side effects can occur in almost anyone who uses the drug, the chances of occurrence are significantly higher in certain groups of people. The following demographics should be cautious when using Neurontin:

  • Children under 18
  • Elderly individuals over 60
  • Pregnant and lactating women
  • Individuals with pre-existing medical conditions, e.g., asthma, emphysema, chronic bronchitis, past episode of tuberculosis or pneumonia

Take Gabapentin as Prescribed

Common adverse effects of Neurontin are numerous. These symptoms are exhibited over a range of body systems and vary depending on the drug’s demographic. Certain sets of individuals should be careful with this medication as the risk of adverse reactions is higher for them.

It is important to take it exactly as prescribed by a doctor. When used as intended, it can even exhibit some desirable features, such as marked improvement in sexual function. However, misuse or abuse of Gabapentin predisposes to sexual dysfunction as well as other side effects.

Page Sources

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Published on: April 10th, 2018

Updated on: March 21st, 2024

About Author

Olivier George, Ph.D.

Olivier George is a medical writer and head manager of the rehab center in California. He spends a lot of time in collecting and analyzing the traditional approaches for substance abuse treatment and assessing their efficiency.

Medically Reviewed by

Michael Espelin APRN

8 years of nursing experience in wide variety of behavioral and addition settings that include adult inpatient and outpatient mental health services with substance use disorders, and geriatric long-term care and hospice care.  He has a particular interest in psychopharmacology, nutritional psychiatry, and alternative treatment options involving particular vitamins, dietary supplements, and administering auricular acupuncture.

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