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Arquivos de Neuro-Psiquiatria

Print version ISSN 0004-282X

Arq. Neuro-Psiquiatr. vol.70 no.12 São Paulo Dec. 2012 



Delirium, psychosis, and visual hallucinations induced by pregabalin


Delírio, psicose e alucinações visuais induzidas pela pregabalina



José Luiz PedrosoI,II; Gilberto Yoshinobu NakamaII,III; Mario Carneiro FilhoII,III; Orlando G. BarsottiniI,II

IDepartment of Neurology, Universidade Federal de São Paulo (Unifesp), São Paulo SP, Brazil
IIHospital Israelita Albert Einstein (HIAE), São Paulo SP, Brazil
IIIDepartment of Orthopaedics, Universidade Federal de São Paulo (Unifesp), São Paulo SP, Brazil




Pregabalin has emerged as a novel drug for neuropathic pain treatment. Few studies or case reports have demonstrated neurological side effects of its use1. The aim of this article was to describe cognitive disturbances induced by Pregabalin in a patient diagnosed with neuropathic pain due to lumbar herniated disc and radicular compression.



A 44-year-old woman presented to Albert Einstein Hospital with lumbar pain, irradiated to the posterior lower left limb. Neurological examination showed Lasègue's sign in the left leg. Lumbar brain magnetic resonance imaging (MRI) disclosed degeneration and bulging herniated disc with left extrusion component, compressing S1 root in the lateral recess. Patient refused surgery, therefore clinical treatment for neuropathic pain was started with anti-inflammatory (diclofenac 50 mg, 3 times daily) and muscle relaxants (ciclobenzaprine 10 mg, twice daily), associated with pregabalin 150 mg, and no side effects were observed. After seven days, the patient still complained of pain. Pregabalin was increased to 300 mg daily. In the third day, she developed structured visual hallucinations and psychosis, irritability, and acute confusional state (temporal and spatial disorientation). General blood exams excluded infection or metabolic abnormalities and the brain MRI was normal. Electroencephalogram showed temporal slow-waves abnormalities and delta waves in frontal regions. No epileptiform discharges were found. We discontinued Pregabalin, and the patient improved mental state after 24 hours. The free informed consent was got from the patient for this publication.



Pregabalin is a gamma-aminobutyric acid analogue in the treatment of neuropathic pain, partial-onset-seizures, fibromyalgia, and anxiety disorders1. Although this is originally an antiepileptic drug, Pregabalin seems to be an effective therapy for the neuropathic pain, and it has been widely used, but few reports have highlighted its neurological side effects.

Recently, Zaccara et al. performed a systematic review and a meta-analysis in a randomized controlled trial, describing the main side effects of Pregabalin use2. The main neurological side effects reported were dizziness, vertigo, incoordination, balance disorder, ataxia, diplopia, blurred vision, amblyopia, tremor, somnolence, confusional state, attention disturbances, abnormal thinking, euphoria, asthenia, and fatigue2. Side effects were more frequent with increasing doses2.

In general, the emergence of acute confusional state or delirium in healthy young people leads to extensive diagnostic investigation for potentially serious illnesses, such as encephalitis, metabolic disorders and infections, however the side effects of drugs should also be considered. Only few reports have described acute confusion state during Pregabalin use3. Also, psychosis has already been described in one patient, but this is a rare condition4.

The efficacy and safety of Pregabalin in the treatment of neuropathic pain have been documented in several recent data5. Hence, neurologists have prescribed Pregabalin more often in daily medical practice. We must be aware of the side effects reported in this article, such as delirium, psychosis and visual hallucinations, since its use has increased greatly in recent years.

In summary, the present report reinforces the idea that acute confusional state, psychosis, and visual hallucinations should be considered in the clinical spectrum of side effects due to Pregabalin use, especially in higher doses, and that the withdrawal of the medication usually improves symptoms.



1. Tassone DM, Boyce E, Guyer J, Nuzum D. Pregabalin: a novel gamma-aminobutyric acid analogue in the treatment of neuropathic pain, partial-onset seizures, and anxiety disorders. Clin Ther 2007; 29:26-48.         [ Links ]

2. Zaccara G, Gangemi P, Perucca P, Specchio L. The adverse event profile of pregabalin: a systematic review and meta-analysis of randomized controlled trials. Epilepsia 2011;52:826-36.         [ Links ]

3. Hickey C, Thomas B. Delirium secondary to pregabalin. Gen Hosp Psychiatry. 2011 [Epub ahead of print]         [ Links ].

4. Olaizola I, Ellger T, Young P, Bösebeck F, Evers S, Kellinghaus C. Pregabalin-associated acute psychosis and epileptiform EEG-changes. Seizure 2006;15:208-210.         [ Links ]

5. Baron R, Freynhagen R, Tölle TR, et al; A0081007 Investigators. The efficacy and safety of pregabalin in the treatment of neuropathic pain associated with chronic lumbosacral radiculopathy. Pain 2010;150:420-427.         [ Links ]



José Luiz Pedroso
Rua Botucatu 740
04023-900 São Paulo SP - Brasil

Received 23 March 2012
Received in final form 05 June 2012
Accepted 12 June 2012

Conflict of interest: There is no conflict of interest to declare.

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