Drug Use Investigation Of Gabapentin

Drug Use Investigation Of Gabapen

The objective of the this surveillance is to collect information about 1)adverse drug reactions not expected from the LPD (unknown adverse drug reactions), 2) the incidence of adverse drug reactions in this surveillance, and 3) factors considered to affect the safety and/or efficacy of this drug.

Study Overview

• Status: Completed
• Conditions: Epilepsies, Partial
• Intervention / Treatment: Drug: Gabapentin

Detailed Description

All the patients whom an investigator prescribes the first Gabapentin should be registered consecutively until the number of subjects reaches target number in order to extract patients enrolled into the investigation at random.

• Study Type: Observational
• Enrollment (Actual): 1273

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: ADULT; OLDER_ADULT; CHILD
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

The patients whom an investigator involving A9451163 prescribes the Gabapentin

Description

Inclusion Criteria:

Patients need to be taking Gabapentin in order to be enrolled in the surveillance

Exclusion Criteria:

Patients not taking Gabapentin

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Gabapentin; Patients taking Gabapentin

Drug: Gabapentin; GABAPEN Tablets 200mg, GABAPEN Tablets 300mg, GABAPEN Tablets 400mg. GABAPEN is Brand name in Japan. Dosage, frequency: According to Japanese LPD, "Normally, oral gabapentin 600 mg, 3 div., should be given on the first day of administration and an effective dose of 1200mg, 3 div, should be given on day 2. From day 3 on, adults should be maintained on oral gabapentin 1200 mg to 1800 mg, 3 div. Subsequently, the maintenance dose should be suitably adjusted depending on the symptoms (up to a maximum daily dose of 2400 mg)". Duration: According to the protocol of A9451163, the duration of the investigation for findings regarding safety and efficacy of a patient is from the first drug administration to the 12 weeks after the first administration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Treatment-Related Adverse Events Unexpected From Japanese Package Insert	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.).	12 weeks
Number of Participants With Treatment-Related Adverse Events	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.).	12 weeks
Clinical Efficacy Rate	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.	12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Response Ratio (R Ratio)	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.	12 weeks
Responder Rate	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.	12 weeks
Percent Reduction From Baseline in Epileptic Seizure Frequency	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.	12 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Treatment-Related Adverse Events by Age Across 7 Categories	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.	12 weeks
Number of Participants With Treatment-Related Adverse Events by Number of Concomitant Antiepileptic Drugs at Baseline	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.	12 weeks
Number of Participants Who Responded to Treatment With Gabapentin by Age (<65 Versus >=65 Years)	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.	12 weeks
Number of Participants Who Responded to Treatment With Gabapentin by Age Across 7 Categories	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.	12 weeks
Number of Participants Who Responded to Treatment With Gabapentin by Severity of Partial Epileptic Seizure	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.	12 weeks
Number of Participants Who Responded to Treatment With Gabapentin by Baseline Frequency of Epileptic Seizure	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.	12 weeks
Number of Participants Who Responded to Treatment With Gabapentin by Number of Concomitant Antiepileptic Drugs at Baseline	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.	12 weeks
Number of Participants Who Responded to Treatment With Gabapentin by Baseline Creatinine Clearance	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.	12 weeks
Number of Participants Who Responded to Treatment With Gabapentin by Presence or Absence of Non-Drug Therapy	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.	12 weeks

Collaborators and Investigators

• Sponsor: Pfizer's Upjohn has merged with Mylan to form Viatris Inc.

Publications and helpful links

Helpful Links

• To obtain contact information for a study center near you, click here.

Study record dates

Study Major Dates

• Study Start: August 1, 2007
• Primary Completion (ACTUAL): May 1, 2014
• Study Completion (ACTUAL): May 1, 2014

Study Registration Dates

• First Submitted: November 16, 2007
• First Submitted That Met QC Criteria: December 3, 2007
• First Posted (ESTIMATE): December 4, 2007

Study Record Updates

• Last Update Posted (ACTUAL): February 3, 2021
• Last Update Submitted That Met QC Criteria: February 1, 2021
• Last Verified: September 1, 2015

More Information

Terms related to this study

• Keywords: Post-Marketing surveillance
• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Epilepsy; Epilepsies, Partial; Physiological Effects of Drugs; Neurotransmitter Agents; Molecular Mechanisms of Pharmacological Action; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Excitatory Amino Acid Antagonists; Excitatory Amino Acid Agents; Tranquilizing Agents; Psychotropic Drugs; Anti-Anxiety Agents; Anticonvulsants; Antimanic Agents; Gabapentin
• Other Study ID Numbers: A9451163