Dose-related side effects
Side effects of Neurontin are generally mild to moderate and transient. The most commonly reported dose-related side effects are:

• drowsiness
• ataxia
• dizziness
• nystagmus
• fatigue

If these problems do not diminish within several days, a reduction in the dose of Neurontin often will solve the problem. Problems with sedation also may be helped by splitting the dose or giving the largest dose at bedtime.

Weight gain occurs in up to 5% of patients and is often accompanied by ankle edema.

The package insert for Neurontin warns that about 5% of children aged 3-12 years in clinical trials developed new behavioral problems (including hostility, aggressive behaviors, or hyperactivity) or trouble with thinking, especially concentration.

There are no known long-term side effects of Neurontin.

Idiosyncratic reactions
No idiosyncratic reactions or effects on bone marrow or hepatic function have been described.