, 1996) and inhibits neuronal glutamate release (Coderre, Kumar, Veliparib cost Lefebvre, & Yu, 2005). Gabapentin activates presynaptic ��-aminobutyric acid type B (GABAB) heteroreceptors (Parker, Ong, Marino, & Kerr, 2004) and elevates the concentration of GABA in the brain (Petroff, Hyder, Rothman, & Mattson, 2000). Activation of GABAB receptors and inhibition of glutamatergic transmission have separately been observed to decrease nicotine self-administration in rodents (Markou, Paterson, & Semenova, 2004). Gabapentin attenuates nicotine withdrawal symptoms and may increase short-term nicotine abstinence (Myrick, Malcolm, Henderson, & McCormick, 2001). In a randomized open-label pilot study including 36 subjects, bupropion SR was associated with higher abstinence rates than gabapentin when given for 6 weeks (prolonged abstinence 26.

3% vs. 5.9%, p = .1821; White, Crockford, el-Guebaly, & Patten, 2005). We recently conducted a pilot study of gabapentin for smoking cessation (Sood et al., 2007). We initiated gabapentin at 300 mg twice daily gradually increasing the dose over 2 weeks to 600 mg three times daily. This dose was maintained for 5 weeks and then tapered over 1 week. After 8 weeks of treatment, the prolonged smoking abstinence rate among participants treated with gabapentin was 24% (95% CI = 13%�C38%). Participants reporting smoking at the 6-month follow-up demonstrated a significant reduction in the number of cigarettes smoked per day compared with baseline (?10.0 �� 8.2, p < .001). In order to further explore gabapentin for smoking cessation, we conducted a proof-of-concept pilot study.

Methods Subjects The Mayo Clinic Institutional Review Board approved this study. Study procedures for the current study were identical to our previous pilot study (Sood et al., 2007). The present study consisted of a phone prescreen interview, two screen visits, nine clinic visits during treatment phase, and two posttreatment visits (one phone visit and one clinic visit). Study treatment All study participants were randomized to one of three study arms. One group received 1,800 mg of gabapentin per day; one received 2,700 mg of gabapentin per day; and one received matching placebo. Gabapentin was initiated at a dose of 300 mg by mouth in the morning and night. The dose was increased over the first 2 weeks to the target doses of 600 and 900 mg three times a day.

This dose was continued for the next 9 weeks and tapered in the last week to minimize the risk of possible medication withdrawal�Crelated seizures (Barrueto, Green, Howland, Hoffman, & Nelson, 2002; Pfizer, 2009). The medication was stopped GSK-3 at the end of 12 weeks. Identical-appearing placebo tablets were used and dispensed according to unique subject identification by assistants who had no subject contact. All participants received the same number of pills at corresponding times during the study.