How long one can stay on gabapentin (neurontin) if being taken for idiopathic rls ??? are there any major side- effects in long run?

Although many potential side effects for gabapentin are listed, I have seen patients on high dose( up to 2700 mgs per day) for prolonged periods of time without problems. Most of the patients on very high doses were given by neurologists that followed the patients with me. I might add that the pharmacy I use keeps track of the prescriptions&refills. Patients are not to abruptly stop the medication

Unlikely to be a problem long-term, and there are few drug-drug interactions. I prefer using dopamine agonists for RLS, but these too have side effects.