Conditions: Smoking Cessation
Keywords: therapeutic effects
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 37
Healthy volunteers: yes

Brief summary:
To examine the effects of varenicline on the subjective, physiological and cognitive responses to intravenous nicotine. Varenicline is a partial nicotine agonist and it is approved as a treatment for smoking cessation. We predict that varenicline treatment will modify subjective, physiological and cognitive responses to IV nicotine.

Detailed description:
This will be a 2-4 week double-blind, placebo-controlled study. Twenty four male and female smokers will have two 4-day treatment periods, in which they will be randomized to varenicline (1 mg/day) or placebo. During the first 3 days of each treatment period, smokers will have daily clinic visits and receive their study medication. On Day 4, subjects will come to the laboratory, where they will receive ascending doses of intravenous (IV) nicotine (0.1, 0.4, and 0.7 mg per 70kg). This procedure will allow accurate assessment of varenicline effects on the subjective, physiological and cognitive responses to nicotine. Following a washout period, subjects will be crossed over to the alternative treatment.

Arms:
arm 1: Subjects received a Placebo tablet once per day for 4 days and then received a laboratory session where they were given ascending doses of Nicotine (0.1, 0.4, and 0.7 mg per 70 kg).After a minimum of a 5 day washout subjects then received varenicline tablet (1mg). once per day for 4 days and then received a laboratory session where they were given ascending doses of Nicotine (0.1,0.4,0.7 mg per 70kg). arm 2: Subjects received Varenicline tablet (1 mg) per day for 4 days and then received a laboratory session where they were given ascending doses of Nicotine (0.1, 0.4, and 0.7 mg per 70 kg). After a washout of a minimum of 5 days subjects then received placebo tablet for per day for 4 days and then received a laboratory session where they were given ascending doses of Nicotine (0.1,0.4,, and 0.7mg per 70 kg).

Interventions: intervention 1: Varenicline intervention 2: Placebo intervention 3: IV Nic
Intervention descriptions: intervention 1: Varenicline (1 mg per day) given for 4 days prior to laboratory session intervention 2: Sugar Pill intervention 3: IV Nicotine given during the laboratory session following 4 days of exposure to the study medication (varenicline or placebo). This nicotine was given during each laboratory session which followed the 4 days of exposure to either placebo then varenicline or varenicline then placebo.

Protocol document: