Gabapentin, the commonly used prescription medicine helps to treat partial seizures, nerve pain from shingles, and restless leg syndrome. Available only with a doctor’s prescription, it comes in varied dosage forms including capsule, tablet, extended-release tablet, oral solution, and suspension. Now, gabapentin normal dosage can vary from person to person. The normal dosage for epilepsy conditions in adults and old children, 12 years and above is 900mg to 3,600mg a day, segregated into 3 doses. For children aged 6 to 12, the dosage can be adjusted according to their body weight. Again.