Results: In 100 drug prescriptions in out-patients, there were 43 cases (43%) with un-logical indication for gabapentin, with total amount of 2120 capsules (accountings for 44.8% of total amount of gabapentin), total cost of 15, 956, 810 VN dong (accounting for 50.6% of total cost of gabapentin), and the mean of un-logical prescriptions was higher than the logical ones (317, 250 versus 280, 000 VN dong) (p = 0.032).