Abstracts

Rationale: Infantile spasms (IS) typically occur in infants between 3 and 12 months of age. IS may be associated with West syndrome, a severe epileptic encephalopathy. IS can be associated with a poor prognosis, particularly when resistant to treatment. Vigabatrin, an irreversible inhibitor of gamma-aminobutyric acid (GABA) transaminase, is one of the three first-line medications for the treatment of IS, in addition to ACTH and high dose oral corticosteroids. Vigabatrin is the treatment of choice for patients with tuberous sclerosis and IS. However, this medication is associated with irreversible visual field constriction, attributed to retinal toxicity. Rodent models showed a decrease in the concentration of the amino acid taurine in those treated with vigabatrin. Taurine supplementation improved components of the retinal lesions in such models. Limited human data suggest low taurine levels in infants treated with vigabatrin. GABA and taurine share a common transporter. The addition of taurine supplementation may allow for competition at the blood-retina barrier, potentially overcoming vigabatrin-induced taurine depletion. We sought to understand current US clinical practice regarding taurine supplementation for children with IS who are treated with vigabatrin. Methods: A survey was designed by the authors to inquire about institutional practice regarding taurine prescription for infants treated with vigabatrin. Respondents who indicated that they recommend taurine were asked details regarding dosing and prescription of this supplement. An electronic link to the survey was emailed to 83 current members of the Pediatric Epilepsy Research Consortium (PERC). These individuals represent 43 pediatric epilepsy centers in the USA. The survey was anonymous, unfunded, and without influence by a pharmaceutical company or conflicting body of interest. An exemption for this survey was granted by our Institutional Review Board. Results: At the time of abstract submission, there were 25 responses (30% response rate). The majority of respondents (11/25) were from the Northeast region of the US, followed by the Midwest (6) and Western (6) regions. Two respondents were from the Southern region and there were no respondents from the Southwest. The majority of respondents (22/25, 88%) reported that their institution did not routinely recommend taurine supplementation for patients taking vigabatrin. Three respondents (12%) reported that their institution routinely recommended taurine supplementation and cited preliminary evidence that this could protect against the retinal toxicity of vigabatrin. These three respondents were asked questions regarding taurine dosage, cost, reason for prescribing and side effects (Table 1). Prescribed taurine doses ranged from 250 mg to 1000 mg daily, with no reported side effects. None of the treated patients had suffered from documented visual field defects. One respondent reported that they wrote a prescription for taurine, which was covered by insurance, while the other respondents reported that their patients typically paid out of pocket for an over-the-counter taurine supplement. Conclusions: This survey was performed to evaluate the prescribing practices for taurine supplementation among pediatric epilepsy experts throughout the US. Most pediatric epileptologists indicated that they do not routinely recommend taurine supplementation for patients who are prescribed vigabatrin. Although human data are lacking, some providers argue that taurine appears to be harmless and may prevent visual field deficits associated with vigabatrin. Further human data are needed to determine if taurine supplementation should be routinely recommended for retinal protection in patients on vigabatrin. Funding: NA