Patient adherence to generic gabapentin: A pragmatic study

Generic medication is cheaper than the original brand. Patient adherence to generic gabapentin has never been studied. The study was a retrospective longitudinal study. All consecutive adult patients of ages >15 years who received gabapentin treatment at Srinagarind Hospital were included. The study period was from August 2011 to March 2013. Initially, all patients received generic gabapentin (Siam Pharmaceutical, Thailand). Physicians could switch to original gabapentin (Neurontin®, Pfizer, USA) if the patients did not improve after generic gabapentin treatment. The rate of original gabapentin switch treatment was calculated. Clinical features of all patients who required original gabapentin were also reviewed. The generic gabapentin was prescribed for 5195 patients during the study period. Of those, 310 patients (6.0%) required switch therapy to original gabapentin. The most common indication of gabapentin in the patients who had the need to switch therapy was neuropathic pain in 266 patients (85.8%). Spondylosis was the most common diagnosis in 229 patients (73.8%) The average generic gabapentin use before original gabapentin therapy was 107 days (SD 94). The reason to switch therapy to original gabapentin was recorded in 22 patients (7.1%) due to ineffective treatment. In conclusion, generic gabapentin therapy is effective as a pain controller in neuropathic pain with adherence rate of 94.0%. Generic gabapentin therapy may reduce cost and budget from the original gabapentin.