Abstracts

Specific withdrawal syndromes have been well-documented following the cessation of treatment with many drugs that affect the central nervous system, including barbiturates, benzodiazepines, tricyclic antidepressants and selective serotonin reuptake inhibitors. Studies have investigated withdrawal symptoms associated with some of the older antiepileptic drugs (AEDs), but the existence of withdrawal syndromes associated with newer AEDs, including lamotrigine, has not yet been investigated., We reviewed the medication profiles of all patients seen by two of the authors at the University of Colorado epilepsy clinic in a six month period. Patients taking lamotrigine were identified and their charts reviewed for complaints of adverse effects of lamotrigine use. In addition, we reviewed the medication profiles of all patients seen in our epilepsy monitoring unit in the same six month period and identified those patients in whom lamotrigine had been decreased or stopped during the EMU admission., We identified five clinic patients who complained of new psychological symptoms while taking lamotrigine. These symptoms included anxiety, emotional lability, irritability, feeling [ldquo]out of it[rdquo] and having racing thoughts. In each case, these symptoms resulted in marked subjective distress and reliably occurred in the one to two hours before the patients were due to take their next dose of medication. All the patients were taking lamotrigine either once or twice a day.
In addition, 29 of 84 consecutive EMU patients were taking lamotrigine, either alone or in combination therapy. Of those patients in whom only lamotrigine was withdrawn in the EMU, two complained of symptoms similar to those described by our clinic patients following their reduction in lamotrigine dose. These symptoms also caused notable patient distress., Withdrawal symptoms, although not widely reported in the literature, can occur in patients taking lamotrigine. This withdrawal syndrome consists largely of anxious feelings, irritability, and asthenia and can be very distressing to patients. Lamotrigine withdrawal symptoms can occur as an end-of dose phenomenon in the outpatient setting and can also complicate inpatient evaluation in the EMU setting. End-of-dose withdrawal from lamotrigine is a clinically significant adverse effect that can hamper successful treatment with this medication. Further study of withdrawal symptoms in this medication and the other newer AEDs is clearly needed.,