From the Guidelines
Gabapentin commonly causes side effects including dizziness, drowsiness, fatigue, and unsteadiness, and it is essential to be aware of these potential effects to minimize morbidity, mortality, and improve quality of life. Many patients also experience peripheral edema (swelling in extremities), weight gain, and blurred vision. Cognitive effects like confusion, memory problems, and difficulty concentrating are frequently reported, especially in older adults. Gastrointestinal side effects include nausea, vomiting, constipation, and dry mouth. Some patients develop mood changes such as irritability, anxiety, or depression. Less common but serious side effects include allergic reactions (rash, itching, swelling), suicidal thoughts, and severe respiratory depression, particularly when combined with opioids or other central nervous system depressants. Abrupt discontinuation can cause withdrawal symptoms including anxiety, insomnia, nausea, pain, and sweating, so gabapentin should always be tapered gradually under medical supervision 1. These side effects occur because gabapentin affects neurotransmitters in the brain, particularly GABA and glutamate systems, which regulate nerve activity throughout the body. Side effects are often dose-dependent and may diminish over time as your body adjusts to the medication.
Key Side Effects
- Dizziness
- Drowsiness
- Fatigue
- Unsteadiness
- Peripheral edema
- Weight gain
- Blurred vision
- Cognitive effects (confusion, memory problems, difficulty concentrating)
- Gastrointestinal side effects (nausea, vomiting, constipation, dry mouth)
- Mood changes (irritability, anxiety, depression)
Serious Side Effects
- Allergic reactions (rash, itching, swelling)
- Suicidal thoughts
- Severe respiratory depression (particularly when combined with opioids or other central nervous system depressants)
Management of Side Effects
- Gradual tapering of gabapentin under medical supervision to prevent withdrawal symptoms
- Monitoring for signs of allergic reactions, suicidal thoughts, and severe respiratory depression
- Adjusting dosage to minimize side effects while maintaining therapeutic efficacy
Recent Evidence
The most recent study on gabapentin, published in 2023, highlights the importance of careful dosing and monitoring to minimize side effects 1. This study emphasizes the need for gradual titration of gabapentin to achieve the desired effect while minimizing adverse effects.
From the FDA Drug Label
The most common adverse reactions associated with the use of gabapentin in adults, not seen at an equivalent frequency among placebo-treated patients, were dizziness, somnolence, and peripheral edema The most common adverse reactions with gabapentin in combination with other antiepileptic drugs in patients >12 years of age, not seen at an equivalent frequency among placebo-treated patients, were somnolence, dizziness, ataxia, fatigue, and nystagmus The most common adverse reactions with gabapentin in combination with other antiepileptic drugs in pediatric patients 3 to 12 years of age, not seen at an equal frequency among placebo-treated patients, were viral infection, fever, nausea and/or vomiting, somnolence, and hostility Gabapentin may cause serious side effects including: suicidal thoughts or actions, changes in behavior and thinking, and serious or life-threatening allergic reactions The most common side effects of gabapentin tablets include: lack of coordination, viral infection, feeling drowsy, nausea and vomiting, difficulty with speaking, tremor, swelling, usually of legs and feet, feeling tired, fever, jerky movements, difficulty with coordination, double vision, unusual eye movement
Common side effects of gabapentin include:
- Dizziness
- Somnolence
- Peripheral edema
- Ataxia
- Fatigue
- Nystagmus
- Viral infection
- Fever
- Nausea and/or vomiting
- Hostility
- Lack of coordination
- Feeling drowsy
- Difficulty with speaking
- Tremor
- Swelling, usually of legs and feet
- Feeling tired
- Jerky movements
- Difficulty with coordination
- Double vision
- Unusual eye movement
Serious side effects of gabapentin include:
- Suicidal thoughts or actions
- Changes in behavior and thinking
- Serious or life-threatening allergic reactions 2 2 2
From the Research
Gabapentin Side Effects
- The most common side effects of gabapentin include dizziness, somnolence, and peripheral edema 3, 4, 5
- Other side effects that have been reported include gait disturbance, urinary incontinence, and altered mental status 4, 6, 7
- The incidence of side effects may be dose-dependent, with higher doses of gabapentin associated with a higher risk of certain side effects such as peripheral edema 6, 5
- However, other side effects such as dizziness and somnolence may be transient and do not necessarily worsen with increasing doses of gabapentin 5
Specific Side Effects
- Dizziness: reported by 19% of patients taking gabapentin 4
- Somnolence: reported by 14% of patients taking gabapentin 4
- Peripheral edema: reported by 7% of patients taking gabapentin at doses of 1800 mg/d or higher 5
- Urinary incontinence: a rare side effect that has been reported in some patients taking gabapentin 7
- Altered mental status: a potential side effect of gabapentin, particularly in older adults taking high doses 6
Management of Side Effects
- The risk of side effects can be minimized by starting with a low dose of gabapentin and gradually increasing the dose as needed and tolerated 3, 6
- Patients should be monitored for signs of side effects and the dose of gabapentin adjusted accordingly 6, 5
- In some cases, side effects may resolve on their own or with a reduction in dose 7, 5