Weight gain may be caused by gabapentin. Weight gain can occur as a side effect of gabapentin. Gabapentin is an anticonvulsant and an analog of gamma amino butyric acid (GABA). It has become the first line of treatment for bipolar disorders, post herpetic neuralgia and restless leg syndrome. There are some common side-effect which occurs during medication like nausea, vomiting, dizziness, and blurred vision/ double vision and sometimes weight gain. Gabapentin and weight gain are not significantly related to each other, as in animal studies weight gain is not a consistent effect of gabapentin. In long term medication, higher dose of gabapentin reduced weight gain in rats.