--who've gone up to 4200-4800mg/day range, and one outlier with Central Pain who continued to get a small increasing amount of relief up to 7200mg/day, and who somehow seemed to shrug off most of the side effects one would anticipate would occur at that high a dose.

Even at lower doses, Gabapentin dosage increases do not tend to have a direct arithmetic added effect--people notice more of an increased effect say, going from 600-1200mg than from 2400-3000mg. But the response is very individual.