Zonisamide or Levetiracetam for Adults With Cyclic Vomiting Syndrome: A Case Series

Zonisamide or Levetiracetam for Adults With Cyclic Vomiting Syndrome: A Case Series RAY E. CLOUSE,* ,‡ GREGORY S. SAYUK,* PATRICK J. LUSTMAN, ‡,§ and CHANDRA PRAKASH* *Division of Gastroenterology and ‡ Department of Psychiatry, Washington University School of Medicine, and § Department of Veterans Affairs Medical Center, St Louis, Missouri Background & Aims: Management of cyclic vomiting syndrome in adults is limited by the small number of effective medications for maintenance therapy. The clinical response to treatment with 2 newer antiepileptic drugs was evaluated retrospectively to see whether they might have a prophylactic role in this syndrome. Methods: Outpatient records from 20 adult patients with cyclic vomiting syndrome attending a university-based practice were reviewed. Each had received zonisamide (median dose, 400 mg/d) or levetiracetam (median dose, 1000 mg/d) because tricyclic antidepressants alone were unsatisfactory as maintenance medications. Outcome was graded from chart review and directed interview; characteristics of the vomiting episodes were compared before and after initiation of antiepileptic drug therapy. Results: At least moderate clinical response was described by 15 (75.0%) subjects, and 4 of these (20.0% of the total) reported symptomatic remission during 9.5 1.8 months of follow-up. Rate of vomiting episodes decreased from 1.3 0.3 to 0.5 0.2 per month (P .01). Tricyclic antidepressants were discontinued in 11 (61.1%) of the 18 subjects who were still taking the medications when antiepileptic drug therapy was initiated. Moderate or severe side effects were reported by 45.0%, but by switching drugs, intolerance to antiepileptic drug therapy occurred in only 1 subject. Conclusions: Newer antiepileptic drugs, specifi- cally zonisamide and levetiracetam, appeared beneficial as maintenance medications for nearly three fourths of adults with cyclic vomiting syndrome in this uncontrolled clinical experience. Although side effects occur in a large proportion of subjects, newer antiepileptic drugs might offer an alternative for patients who fail conventional treatment. C yclic vomiting syndrome (CVS) is an uncommon disorder manifested by recurrent, stereotypical episodes of vomiting separated by symptom-free intervals. 1 The disorder origi- nally was described in children, but onset of symptoms in adulthood is being recognized increasingly. 2– 4 Similar to that for other idiopathic recurring disorders, the management ap- proach includes abortive strategies to terminate acute episodes and maintenance medications for prophylaxis against attacks. Because of the rarity of the condition, evidence favoring medications for either component of management has been re- stricted to uncontrolled case reports or small series. 5 Neverthe- less, the cumulative findings have been sufficiently useful to fashion treatment guidelines for this disorder. 6 The most commonly used maintenance medications in adults with CVS have been the tricyclic antidepressants (TCAs). 2 TCAs are ineffective in one fourth of patients and have side effect profiles that make them unsuitable for chronic use in a smaller proportion of patients with CVS, a disorder that remains clinically active in adults for at least 8 years on average if untreated. 3 Newer antiepileptic drugs, including zonisamide and levetiracetam, have found a niche as prophylactic agents against migraine headache, a condition sharing many clinical features with CVS. 7,8 Although an older antiepileptic agent (phenobarbital) has been used for maintenance therapy in children with CVS and topiramate (a newer antiepileptic drug approved for seizure control in pediatric and adult patients) has been suggested for children with CVS, the outcome of newer antiepileptic drugs for any age group with CVS has not been reported. 5 We describe the outcome of 20 adult patients with CVS who were treated clinically with zonisamide or levetiracetam for prophylaxis against CVS episodes. In each subject, TCAs alone had failed to control episode frequency adequately, were poorly tolerated, or were otherwise unsuitable for use. We hypothe- sized that the findings from this unblinded clinical experience would be useful in determining whether newer antiepileptic drugs might have a role in the maintenance therapy of adult patients with CVS. Methods Outpatient records from all subjects treated with zonisamide or levetiracetam from June 2003 through December 2005 by either of 2 authors (R.E.C., C.P.) for management of CVS were reviewed. Twenty subjects were identified. Clinical features of the subject group are shown in Table 1. The diag- nosis of CVS was based on published clinical criteria 2,9 ; the symptomatic presentation required at least 3 discrete stereotypical episodes of severe vomiting separated by symptom-free intervals of at least 2 weeks with no structural or metabolic explanation for the symptoms. Most subjects had many episodes by the time of evaluation, and the total duration of illness typically exceeded 6 years (Table 1). The subjects underwent diagnostic testing, as required, to exclude structural gastroin- testinal, metabolic, and neurologic disorders that might be responsible for the symptoms. Demographic and illness characteristics of the 20 subjects resembled those of adult CVS patients reported previously. 2 Review of clinical records for the Abbreviations used in this paper: AED, antiepileptic drug; CVS, cyclic vomiting syndrome; TCA, tricyclic antidepressant. © 2007 by the AGA Institute 1542-3565/07/$32.00 doi:10.1016/j.cgh.2006.10.004 CLINICAL GASTROENTEROLOGY AND HEPATOLOGY 2007;5:44 – 48

Zonisamide or Levetiracetam for Adults With Cyclic Vomiting Syndrome: A Case Series

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