Drug Use Investigation Of Gabapentin

A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Expectedness of the adverse event was determined according to the Japanese package insert. Relatedness to gabapentin was assessed by the sponsor (Pfizer Japan Inc.).

A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Relatedness to gabapentin was assessed by the sponsor (Pfizer Japan Inc.).

Clinical efficacy rate, which was defined as the percentage of participants who achieved clinical efficacy over the total number of efficacy analysis population, was presented along with the corresponding exact 2-sided 95% CI. For the basis of efficacy evaluation, frequencies of epileptic seizure were recorded for the periods during the previous 4 weeks from the treatment start date, and that from the end date of observation (12 weeks after the treatment start date, or date of which treatment was terminated before reaching 12 weeks). Clinical efficacy was assessed according to the following categories: (1) effective, (2) not effective, or (3) not assessable.

Response Ratio (R Ratio) was calculated by the following formula, where B represented the frequency of epileptic seizures during 4 weeks before gabapentin treatment, whereas T represented the frequency of epileptic seizures during 4 weeks at the end of observation period of gabapentin treatment: R Ratio= (T-B) / (T+B). R Ratio was within the range of -1 to +1, and a negative value represented a reduction in the frequency of seizure.

Responder rate, which was defined as the percentage of participants whose R ratio was -0.333 or less, was presented along with the corresponding exact 2-sided 95% CI. R ratio of -0.333 or less corresponded to the decrease of epileptic seizure frequency by 50% or more.

Percent reduction from the baseline in epileptic seizure frequency, was calculated by the following formula, where B represented the frequency of epileptic seizures during 4 weeks before gabapentin treatment, whereas T represented the frequency of epileptic seizures during 4 weeks at the end of observation period of gabapentin treatment: Reduction from the baseline in epileptic seizure frequency (%) = [(T-B)/B] X 100.

A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Participants with treatment-related adverse events were counted by age across 7 categories to assess whether the age was a risk factor for the treatment-related adverse events.

A treatment-related adverse event was any untoward medical occurrence attributed to gabapentin in a participant who received gabapentin. Participants with treatment-related adverse events were counted by the number of concomitant antiepileptic drugs at baseline across 5 categories to assess whether the number of concomitant antiepileptic drugs at baseline was a risk factor for the treatment-related adverse events.

Participants who responded to the treatment with gabapentin were counted by age (<65 vs. >=65 years) to assess whether the age was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by age across 7 categories to assess whether the age was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the severity of partial epileptic seizure (mild, moderate and severe) to assess whether the severity of partial epileptic seizure was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the baseline frequency of epileptic seizure (<=8 vs. >8 episodes) to assess whether the baseline frequency of epileptic seizure was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the number of concomitant epileptic drugs at baseline across 5 categories to assess whether the number of concomitant epileptic drugs at baseline was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the baseline creatinine clearance (CLcr) across 6 categories to assess whether the baseline CLcr was a factor affecting the treatment efficacy.

Participants who responded to the treatment with gabapentin were counted by the presence or absence of non-drug therapy to assess whether the non-drug therapy was a factor affecting the treatment efficacy.