Editing Phenytoin (section)

===Neurological===
At therapeutic doses, phenytoin may produce [[nystagmus]] on lateral gaze. At toxic doses, patients experience vertical nystagmus, [[diplopia|double vision]], [[sedation]], slurred speech, cerebellar [[ataxia]], and [[tremor]].<ref>{{cite web |title=Dilantin Toxicity |url= http://www.fpnotebook.com/neuro/pharm/DlntnTxcty.htm |url-status=live |archive-url= https://web.archive.org/web/20140419011512/http://www.fpnotebook.com/neuro/pharm/DlntnTxcty.htm |archive-date=19 April 2014 | publisher = Family Practice Notebook, LLC }}</ref> If phenytoin is stopped abruptly, this may result in increased seizure frequency, including [[status epilepticus]].<ref name="FDA drug label"/><ref name=PI />

Phenytoin may accumulate in the [[cerebral cortex]] over long periods of time which can cause [[atrophy]] of the [[cerebellum]]. The degree of atrophy is related to the duration of phenytoin treatment and is not related to dosage of the medication.<ref>{{cite journal | vauthors = De Marcos FA, Ghizoni E, Kobayashi E, Li LM, Cendes F | title = Cerebellar volume and long-term use of phenytoin | journal = Seizure | volume = 12 | issue = 5 | pages = 312–315 | date = July 2003 | pmid = 12810345 | doi = 10.1016/s1059-1311(02)00267-4 | doi-access = free }}</ref>

Phenytoin is known to be a causal factor in the development of [[peripheral neuropathy]].<ref>{{cite book | vauthors = Donofrio PD | chapter = Medicine Related Neuropathy | veditors = Donofrio PD |title=Textbook of Peripheral Neuropathy |date=2012 |publisher=Demos Medical Publishing |location=New York |isbn=978-1-936287-10-9 | page = 208 | chapter-url = https://books.google.com/books?id=ozIep65VKkYC&pg=PA208 }}</ref>