What are the side effects of Gabapentin (Neurontin)?

From the Guidelines

Gabapentin commonly causes side effects including dizziness, drowsiness, fatigue, and unsteadiness which affect about 10-20% of patients. Other frequent side effects include peripheral edema (swelling in extremities), blurred vision, dry mouth, weight gain, and cognitive issues like difficulty concentrating or memory problems. Some patients experience mood changes including depression, anxiety, or in rare cases, suicidal thoughts. Gastrointestinal effects like nausea, vomiting, constipation, or diarrhea may occur. These side effects typically emerge when starting treatment or increasing dosage, and often diminish over time as the body adjusts. Starting with a low dose (such as 100-300mg daily) and gradually increasing can minimize side effects. Gabapentin works by binding to calcium channels in the nervous system, modulating neurotransmitter release, which explains both its therapeutic effects and side effect profile. Abrupt discontinuation should be avoided as it can cause withdrawal symptoms including anxiety, insomnia, and even seizures in some cases. If side effects become problematic, patients should consult their healthcare provider rather than stopping the medication suddenly.

Key Points to Consider

• The most recent and highest quality study 1 suggests that gabapentin can be effective in treating unexplained chronic cough, but it also highlights the potential for significant adverse effects.
• The study recommends starting with a low dose and gradually increasing as needed and tolerated, with a maximum daily dose of 1800mg.
• Patients should be closely monitored for adverse effects, and the risk-benefit profile should be reassessed at 6 months.
• Other studies 1 also report similar side effects and recommendations for gabapentin use.

Recommendations for Use

• Start with a low dose (100-300mg daily) and gradually increase as needed and tolerated.
• Monitor patients closely for adverse effects, particularly dizziness, drowsiness, fatigue, and unsteadiness.
• Reassess the risk-benefit profile at 6 months and adjust the treatment plan as needed.
• Avoid abrupt discontinuation to prevent withdrawal symptoms.

From the FDA Drug Label

Gabapentin tablets can cause serious side effects including:

1. Suicidal Thoughts.
2. Changes in behavior and thinking - Using gabapentin tablets in children 3 to 12 years of age can cause emotional changes, aggressive behavior, problems with concentration, restlessness, changes in school performance, and hyperactivity.
3. Gabapentin tablets may cause serious or life-threatening allergic reactions that may affect your skin or other parts of your body such as your liver or blood cells.

The possible side effects of gabapentin tablets include:

• Serious side effects:
  • Suicidal thoughts
  • Changes in behavior and thinking
  • Serious or life-threatening allergic reactions
• Common side effects:
  • 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 2 2 2

From the Research

Gabapentin Side Effects

• There are no direct research papers on Gabapentin side effects in the provided studies, however, some studies discuss the side effects of Pregabalin, which is a similar medication.
• Pregabalin has been associated with changes in mood, depression, and suicidal ideation 3, 4.
• Some case studies have reported that patients developed severe depressive syndrome and even attempted suicide after taking Pregabalin 3.
• It is recommended that patients taking Pregabalin should be warned of and monitored for deterioration in mood 4.
• While there are no direct studies on Gabapentin, it is worth noting that cognitive therapy and antidepressant medications have been shown to decrease suicidal ideation in patients with depression 5, 6.
• Cognitive behavioral therapy for suicide prevention (CBT-SP) has been recommended as an empirically supported treatment approach for suicidal patients 6.