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Background and Aims The most commonly noted adverse effects of pregabalin include sedation, dizziness, peripheral edema and dry mouth. Oculomotor manifestations associated with pregabalin have rarely been reported. Positional upbeat nystagmus caused by pregabalin has not been reported. I report a case of patient who developed vertiginous giddiness and upbeat nystagmus during treatment with pregabalin.

Results A 36-year-old female patient with recent lumbar intervertebral disc surgeries was admitted. She underwent left L4/5 posterior decompression for left foot drop and numbness 5 months ago. She underwent L4 to L5 posterior decompression and discectomy for right lower limb pain and numbness 3 months prior to this admission. Pregabalin dose was increased 150-50-150mg daily by pain team 20 days prior to this admission to optimize pain control. She complained of severe vertiginous giddiness during turning her head to left and getting up from bed on the day of admission. Bilateral severe upbeat nystagmus was noted during roll test. Upbeat nystagmus was also noted on left side-lying test. The laboratory tests were unremarkable. Brain magnetic resonance image was normal as well. Dose of pregabalin was reduced to 150-150mg daily. Vertiginous giddiness and upbeat nystagmus were resolved within 2 days of reducing pregabalin dose.

Conclusions Pregabalin binds to the α2 δ-1 and α2 δ-2 subunit of voltage-gated calcium channels. It is known that α2 δ-1 is present in cerebral cortex, hippocampus and cerebellum, and α2 δ-2 is concentrated in the cerebellum. Decreased excitatory inputs from brain, especially cerebellum by pregabalin may result in functional disturbance of the cerebellum.