[Pharmacologically-caused eye movement disorders--differential diagnosis and mechanisms of action]

The variety of drug induced patterns of pathological eye movements is reviewed with emphasis on hydantoins, barbiturates, carbamazepine, benzodiazepines, amitriptyline and alcohol. These different substances may be analogous or distinct in their site of action within the labyrinths, brain stem and cerebellum. Ocular oscillations are described in correlation to drug uptake or serum levels such as positional, downbeat, gaze evoked, periodic alternating nystagmus as well as saccadic pursuit, slowing down of saccades, alteration of VOR gain or suppression by fixation, internuclear and complete ophthalmoplegia. Most of the ocular motor disturbances are possibly due to a pharmacologically induced transient dysfunction of the vestibulo-cerebellar flocculus loop.