Carisoprodol Withdrawal Syndrome Misdiagnosed as a Psychotic Disorder

Abstract

Typical meprobamate withdrawal symptoms may include anxiety, insomnia, vomiting, tremors, muscle twitching, and ataxia (1). Some patients also demonstrate hallucinations and other psychotic symptoms. Recently, withdrawal from carisoprodol, which is metabolized to meprobamate, was reported with similar symptoms (2). Described here is a patient with carisoprodol withdrawal misdiagnosed as a psychotic disorder.A 25-year-old male with no history of mental illness or medical problems was hospitalized after acutely developing auditory and visual hallucinations and paranoia. Two days prior he was reported to have been having no problems. To examination he was tremulous, suspicious, easily agitated, and responding to internal stimuli. He admitted seeing small animals and flashes of brightly colored light and hearing multiple voices. Physical examination was unremarkable. Laboratory studies were within normal limits, and urine drug screen was negative for cocaine, amphetamines, cannabis, opiates, and benzodiazepines. Ethanol level was not detectable. MRI of the brain was normal.He was started on risperidone 2 mg daily and was given haloperidol and lorazepam as needed to control agitated or psychotic behavior. Over the next 3 days his symptoms gradually resolved, and he was discharged with a diagnosis of Psychotic Disorder NOS. At a follow-up visit two weeks later, his examination was entirely normal, and he related that he had not filled his risperidone prescription after leaving the hospital.A few months later the patient again required admission with a similar acutely psychotic presentation. Medical and laboratory evaluation were again unremarkable. He was treated with haloperidol and lorazepam as needed while his symptoms resolved over the following four days. He was questioned extensively and admitted that he had been prescribed carisoprodol for back spasms and had liked the relaxed feeling he experienced with the drug. He began buying it on the street and ultimately progressed to taking 30 or more tablets daily. He denied misuse of other drugs or alcohol. On the occasions of his two psychotic episodes, he had abruptly stopped taking carisoprodol because he could not obtain it. He had developed anxiety, insomnia, and hallucinations within 48 hours of cessation both times. After this revelation he was treated for substance abuse and has had no recurrence of psychotic symptoms.Meprobamate is a controlled substance with recognized potential for abuse and for withdrawal symptoms with abrupt cessation of intake. It is no longer widely prescribed. Carisoprodol, which is not a controlled substance at the Federal level, is commonly used as a muscle relaxant. However, there is increasing evidence of its abuse potential (3).Almost 20% of individuals with meprobamate withdrawal experience hallucinations or other psychotic symptoms (1), and the previous report of carisoprodol withdrawal involved a patient with vivid hallucinations and bizarre behavior (2). Carisoprodol/meprobamate withdrawal should be considered in the differenti...