PURPOSE: Our aim was to monitor the use of gabapentin (GBP) by patients 
prescribed this drug by primary care physicians in England soon after it was 
marketed in the United Kingdom.
METHODS: A noninterventional observational cohort study was conducted by using 
the technique of prescription-event monitoring. Patients were identified from 
dispensed National Health Service prescriptions. Outcome data were obtained from 
questionnaires sent to the doctor approximately 6 months after the initial 
prescription. These data included demographic information, events reported since 
starting GBP, and reason for stopping the drug, if it was stopped. Incidence 
rates were calculated for given periods for all events reported. Additional 
information was requested for selected events of medical interest, including 
pregnancies. Standardised mortality ratio (SMR) was calculated.
RESULTS: The cohort comprised 3,100 patients, of whom 136 (4%) were children. 
The median duration of treatment was 8.1 months. The most frequently reported 
adverse events reported during the first month of treatment, 
drowsiness/sedation, dizziness, and malaise/lassitude, also were the commonest 
reasons for discontinuing GBP and reported as suspected adverse drug reactions 
(ADRs). There were no congenital anomalies in the 11 babies born to women who 
used GBP during the first trimester of pregnancy. Crude mortality rate was 5 
times that in general population but similar to that in other published studies.
CONCLUSIONS: Neurologic-related events were the most frequently reported adverse 
events. They also were the commonest reasons for discontinuing treatment and 
reported as suspected ADRs. No previously unrecognised adverse events were 
detected in this large cohort of patients who were among the first treated with 
gabapentin in England.