Abstracts

Rationale: The post-marketing experience with efficacy and tolerability of new antiepileptic drugs (AEDs) in clinical practice can be different than in controlled trials. Pregabalin (PGB) is the latest marketed AED, with 40-50% responder rate and only 15% drop-out rate in add-on clinical trials. We analyzed efficacy and tolerability of add-on PGB in all patients started on PGB between September 2005 and December 2006.Methods: The patient records were retrospectively reviewed for all patients started on PGB for epilepsy between September 2005 and December 2006 in the epilepsy clinics of two adult epileptologists. We included only patients started on PGB for refractory partial epilepsy, who had at least one follow up visit or phone communication. We recorded demographic characteristics, seizure types, baseline AEDs, initial and maximal dose of PGB, seizure frequency prior to and after PGB, weight before and after PGB treatment, adverse experiences, duration of PGB treatment, and reason for discontinuing PGB. Tolerability data used all patients who qualified for the study. Efficacy measurements were possible only for patients treated for at least 12 weeks. We used only complex partial and secondarily generalized seizures for measuring efficacy. Results: 119 patients (54 women) qualified for the study. Their mean age was 39.5 years (range 12 to 78). 73 patients (61%) were still taking PGB at the last follow up. The average duration of treatment was 41 weeks. 33% (15/46) of patients who discontinued PGB did so for lack of efficacy only while the other 66% (31/46) stopped the medication for adverse effects alone or for both. The average length of treatment for those who discontinued PGB was 11 weeks. The most common adverse effect causing discontinuation was behavioral and psychiatric adverse effects, including agitation, irritability, and depression (9 patients - 20% of those discontinuing). The most common adverse effect overall was drowsiness (23 patients- 19% of all patients). Weight gain was the second most common reason for discontinuation, in 7 patients (15% of those discontinuing). We measured weight only in patients who took PGB for at least 12 weeks and excluding a patient who died with leukemia (87 patients). The average weight change was +12 pounds (range -8 to +71). The average weight change per month was 1.1 lb. The average percent change in weight was +7.7% of starting weight. 29 (33%) patients had >10% increase in weight. There were 88 patients who qualified for efficacy analysis. The median reduction in seizure frequency was 41%. Seven patients (8%) became seizure free, 13 patients (15%) reported >90% seizure reduction, 38 patients (43%) reported >50% seizure reduction, 20 patients (46%) reported no significant change, and 10 patients (11%) had greater than 50% increase in seizure frequency. Conclusions: PGB efficacy post-marketing is similar to that noted in clinical trials. However, behavioral adverse effects which were not reported in controlled trials were the most important reason for discontinuation. Weight gain is the second most common.